Copyright: (c) Copyright Agilent Technologies, 2000, 2001


About This Reference

The online-help Reference documentation contains details about standard features available with Agilent 89600-Series VSA software. Agilent 89600-Series VSA software includes both the Spectrum Analyzer application and the Vector Signal Analyzer application. The following tables summarize some of the primary features available for these applications. Each VSA Optional Measurement Software application provides additional information about their own feature set (see About Optional Measurement Software).

Available Features

Feature	Spectrum Analyzer	Vector  Signal Analyzer
Analog Demodulation	No	yes
Digital Demodulation	No	yes (optional†)
Phase information	no	yes
Time data	no	yes
Gating	no	yes
Time capture	no	yes
Very narrow RBWs	yes	no
Wide frequency spans	yes	No
Integrated source link	No	Yes
EEsof/ADS dynamic link	No	yes (optional†)
†	Optional 89600 Measurement Software.

Available Measurement Data

For detailed information on any of these data types, see Available Trace Data.

Measurement Data  †	Spectrum Analyzer	Vector Signal Analyzer
Spectrum	yes	yes
Math Functions	yes	yes
Data Registers	yes	yes
PSD	yes	yes
Instantaneous Spectrum	no	yes
Time	no	yes
Gated Time	no	yes
Auto Correlation	no	yes
CCDF	no	yes
CDF	no	yes
PDF	no	yes
Frequency Response	no	yes ††
Coherence	no	yes ††
Cross Correlation	no	yes ††
Cross Spectrum	no	yes ††
Impulse Response	no	yes ††
†	Does not include measurement data for the "Optional Measurement Software" applications (Digital Demodulation,
1xEV-DO, cdma2000, W-CDMA, TD-SCDMA, WLAN-OFDM, or WLAN-DSSS demodulation.

††	This is a two-channel measurement and requires two input channels.

Available Trigger Types

For detailed information about these trigger types, see Trigger Types.

Trigger Types †	Spectrum Analyzer	Vector Signal Analyzer
Free Run	yes	yes
Channel 1 or 2 ††	yes	yes
IF Channel 1 or 2	no	yes
External	yes	yes
†	Available trigger types may vary for non-VXI measurement hardware.

††	Channel trigger is not available in the 89640 or 89641 for RF measurements.

Available Average Types

For detailed information about these average types, see Selecting an Average Type.

Average Types	Spectrum Analyzer	Vector Signal Analyzer
rms	yes	yes
rms Exponential	yes	yes
Time	no	yes
Time Exponential	no	yes
Continuous peak hold	yes	yes

Available Data Sources

Data Source	Spectrum Analyzer	Vector Signal Analyzer
From hardware	yes	yes
From a file (record and       playback)	no	yes
From ADS interface	no	yes


Digital Demodulation

Digital Demodulation is optional software that you can order with the 89600 VSA software. For more information, see Digital Demodulation

For information about other software options, see Optional Measurement Software .


Advanced Design System (ADS) Connectivity

Advanced Design System (ADS) Connectivity is optional software (option 105) that you can order with 89600 products. This option allows you to integrate your 89600-Series VSA software to the Agilent EEsof Advanced Design System (ADS). See Advanced Design System Connectivity for more information.

For information about other software options, see Optional Measurement Software .


3G Cellular Modulation Analysis

3G Cellular Modulation Analysis is optional software (option number B7N) that you can order with the 89600 VSA software. This option extends Option AYA Vector Modulation Analysis capabilities to include the following demodulation capabilities:

•	W-CDMA(3GPP) vector modulation analysis

•	cdma2000 vector modulation analysis

•	1xEV-DO vector modulation analysis

•	TD-SCDMA Modulation Analysis :  Adds TSM "TD-SCDMA System for Mobile" and N-TDD "ULTRA TDD - Low Chip Rate (or Narrow TDD)" vector modulation analysis.

For information about other software options, see Optional Measurement Software .


802.11a and HIPERLAN/2 OFDM Modulation Analysis
Wireless Networking Modulation Analysis

Wireless Networking Modulation Analysis is optional software (option number B7R) that you can order with the 89600 VSA software. This option extends Option AYA Vector Modulation Analysis capabilities to include the following wireless LAN demodulation capabilities:

•	WLAN-OFDM 802.11a and HIPERLAN/2   vector modulation analysis.

•	WLAN-DSSS 802.11b and 802.11g vector modulation analysis.

•	Agilent 89600 WLAN Test:  Agilent 89600 WLAN Test is a software application that provides a set of automated tests that validate conformance to the IEEE 802.11a-1999 TX specification.  The WLAN Test application is installed separately from the Agilent 89600 VSA application.

For information about other software options, see Optional Measurement Software .


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Acknowledgements

The following products are mentioned in one or more places in the Agilent 89600-series documentation.

Product	Acknowledgement
Adobe® and Acrobat®	These products are trademarks of Adobe Systems Incorporated.
Microsoft®, Windows NT®, Windows®, and MS Windows®	These products are U.S. registered trademarks of Microsoft Corporation.
MS Excel, MS Word, MS Office, VBScript	These products are products of Microsoft Corporation.
MATLAB	MATLAB is a product of The MathWorks, Inc.


The Documentation Roadmap is not installed on your system.


1999-2002, Agilent Technologies


This documentation is not installed on your system.


This document was not available for inclusion in the online help. You can download the PDF from the 89600 [image] Web page .


This document was not available for inclusion in the online help. You can download the PDF from the 89600 [image] Web page .


This document was not available for inclusion in the online help. You can download the PDF from the 89600 [image] Web page .


About Averaging

Averaging minimizes the effects of noise. When averaging is on, the current trace is averaged, point-by-point, with the averaged results of preceding traces. Subsequent traces are included in the average in the same way, until the analyzer reaches the number of averages you've specified in the Count field.

Note

Averaging uses the data block represented by the displayed trace, not the trace itself.

For example, suppose you specify 3 averages. For the first average, the analyzer clears previous trace data and obtains a new trace. The second average is the average of the next trace and the first trace. The third average is the average of the third trace with the averaged results of the first two traces.

The analyzer updates the display after each average. In this example, the analyzer would update the display three times, once for each average (even though the first trace really isn't "averaged").

During averaging, the status area (very bottom of the application window) displays the messages "Average in Progress" and then "Average Complete". Also, the type of average and the number of the current average are displayed above the top center of the grid.

See also

Selecting an Averaging Type

Pausing an Averaged Measurement

Average Tab (MeasSetup)

Averaging with Digital Demodulation

Repeat Averaging

Fast Averaging

Count

Update Rate


Average Tab (MeasSetup)

Menu Path: MeasSetup > Average

The Average tab lets you set averaging parameters and turn averaging on or off.

Note

If a particular average type is not available in the list for your analyzer, it is because your hardware does not support that trigger type.

•	Average Type lets you select an averaging function.

−	Continuous Peak-Hold Averaging

−	Exponential Averaging

−	RMS (Video) Averaging

−	RMS (Video) Exponential Averaging

−	Time Averaging

−	Time Exponential Averaging

•	Count specifies the number of averages to perform.

•	Repeat Average is valid only for linear average types and causes the analyzer to continue instead of stopping after completing the average.

•	Fast Average is used to increase measurement speed for some configurations. When Fast Average is enabled, the analyzer updates the display only after accumulating the number of averages specified by Update Rate.

•	Update Rate is used with Fast Average (described above).

See also

Pausing Averaging

Selecting an Averaging Type

About Averaging

Averaging with Digital Demod, WCDMA, and cdma2000 demodulation


Selecting an Averaging Type

Several types of averaging functions are available, but not all average types are available for all measurement hardware.

Note

If your hardware does not support a particular average type, that average type is greyed in the menu and you cannot select it.

For both RMS and time averaging, the analyzer provides linear or exponential averaging. Linear averaging gives uniform weight to all data used in the average. Exponential averaging weights new data more than old data, which is useful for tracking data that change over time.

By default, exponential averaging continues indefinitely. This differs from the default for linear averaging, which stops when the analyzer reaches the number of averages specified. However, you can configure the analyzer to perform consecutive linear averages by selecting the Repeat Average check box.

Available Average Types:

•	Continuous Peak-Hold Averaging

•	RMS (Video) Averaging

•	RMS (Video) Exponential Averaging

•	Time Averaging

•	Time Exponential Averaging

See also

Average Tab

Pausing Averaging

About Averaging


Pausing an Averaged Measurement

There may be times when you want the analyzer to pause after each average. To do this, follow these steps:

1.	Set Sweep to single. Click Control > Sweep > Single.

2.	Select the type of averaging you want to perform.

a.	Click MeasSetup > Average, and the arrow ( [image] ) below Average Type.

b.	Select the average type from the pull-down list.

3.	Set the number of averages.

a.	Click the text box below Count.

b.	Type the number of averages you want to perform and press Enter.

c.	Click Close.

4.	Click the Restart button ( [image] ) to take the first average. The analyzer takes one measurement, then pauses.

5.	Click the Pause/Single button ( [image] ) once for each additional average you want to include in the measurement. For example, if the number of averages is set to 3, click Pause/Single twice. Each click of the Pause/Single button takes another measurement and averages it with the accumulated average.

To learn more about how to start, pause, or resume an averaged measurement, see the following topics:

Starting a Measurement

Pausing and Single-Stepping a Measurement

See also

Selecting an Averaging Type

Average Tab (MeasSetup)

Averaging with Digital Demod, WCDMA and cdma2000 demodulation

About Averaging


Averaging with Digital Demodulation, W-CDMA and cdma2000
Averaging with Digital Demodulation

(Vector Signal Analyzer application only.)

In general, averaging is not available for demodulated trace data in Digital Demodulation, W-CDMA, cdma2000, or OFDM demodulation, except for RMS averaging on pre-demodulated spectrum trace data. Averaging may be applied to most numeric-error data in the Error Summary table as it applies to each demodulation format:

•	RMS (Video) and Time computes an RMS average of each RMS error update in the error summary table (does not average peak error data).

•	RMS (Video) and Time Exponential is like RMS (video) and time, except that averaging continues past the average count with an exponential weight (does not average peak error data).

•	Continuous Peak Hold keeps track of the peak RMS error of each update in the error summary table.

Specific averaging information for each demodulation format is found in the following topics:

•	Digital Demodulation

−	Available features (Digital Demod)

−	About Error parameters (Digital Demod)

•	W-CDMA(3GPP) Demodulation

−	Available Features (W-CDMA)

−	About the Error Summary Table (W-CDMA)

•	cdma2000 Demodulation

−	Available Features (W-CDMA)

−	About the Error Summary Table (W-CDMA)

•	WLAN-OFDM Demodulation

−	Available Features (OFDM)

−	About Error Summary Table (OFDM)

•	WLAN-DSSS/CCK/PBCC Demodulation

−	Available Features (WLAN-DSSS/CCK/PBCC)

−	About Error Summary Table (WLAN-DSSS/CCK/PBCC)

•	IxEV-DO Demodulation

−	Available Features (IxEV-DO)

−	About Error Summary Table (IxEV-DO)

•	TD-SCDMA Demodulation

−	Setting Up a Measurement (TD-SCDMA)

−	About Error Summary Table (TD-SCDMA)

See also

Selecting an Averaging Type

Pausing an Averaged Measurement

Average Tab (MeasSetup)

About Averaging topic


Continuous Peak-Hold Averaging

Menu Path: MeasSetup > Average

Continuous peak-hold averaging compares each data point in the measured frequency span with previous values. The analyzer saves only the value with the largest magnitude for each frequency point.

The comparison begins when you begin a measurement. The analyzer displays "PEAK: N" where N is the number of averages taken. Continuous peak-hold averaging continues indefinitely until you stop or pause the measurement.

Note

Continuous peak-hold averaging has no effect on time-domain traces. It only applies to spectrum traces.

Technically, continuous peak-hold averaging is not really a type of averaging, because the results are not mathematically averaged. But it's still considered a type of averaging because it combines the results of several measurements into one final measurement result.

With the continuous peak-hold function, the analyzer mathematically compares the magnitude of each data point to its previous peak value. If the data point is larger than its last peak value, the new value is used. This is not the same thing as peak-holding the displayed trace.

Additional Details

Here are some additional details about continuous peak-hold averaging:

•	It is a measurement function, not a display operation.

•	It operates only on the magnitude of spectrum data. Therefore, continuous peak- hold averaging is available only on spectrum data (spectrum and PSD).

•	Cross channel measurements are not meaningful and are not allowed if continuous peak-hold averaging is selected.

Hint

For averaging formulas, see online help for the type of measurement data selected. For example, refer to the help topic for spectrum measurements, which includes formulas that show how the analyzer creates averaged spectra.

See also

Average Tab

Pausing Averaging

About Averaging


Exponential Averaging

(Vector Signal Analyzer application only.)

Menu Path: MeasSetup > Average

The analyzer offers several types of averages for averaged measurements. Some of these use exponential averaging. Unlike linear averaging (also called non-exponential or normal averaging), exponential averaging weights new data more than old data. This is useful for tracking data that changes over time.

With exponential averaging, the number of averages you select determines the weighting of old versus new data. As the number of averages increases, new data is weighted less.

With exponential averaging, it's especially important to set the number of averages carefully. If there are too few averages in the measurement, the averaging does not smooth out variances. But if there are too many averages, the analyzer may not track subtle changes occurring within the data.

To calculate the exponential average, the analyzer uses this formula:

where N is a weighting factor (the number of averages you've specified).

When you start an exponential average, N equals 1 for the first average, 2 for the second average, and so on, until N equals the number of averages you've specified. This reduces the variance quickly during the startup of an exponential average.

Note

Above the trace, an annotation displays "AVG: N" (where AVG indicates the average type, and N shows the current average.) For exponential averages, when N equals the number of averages you've specified, the analyzer no longer increments N, even though it continues to collect averages.

Until the measurement reaches the specified number of averages, there is no difference between rms (video) exponential averaging and rms (video) averaging.

By default, exponential averages continue indefinitely. This is different than the default for non-exponential averages, which stop when the analyzer reaches the number of averages specified. However, you can configure the analyzer to stop during an exponential average using single sweep or you can pause an exponential average using Pause/Single.

See also

Average Tab

Pausing Averaging

About Averaging


RMS (Video) Averaging

Menu Path: MeasSetup > Average

This type of average reduces the variance of each point's magnitude, which has the effect of smoothing the noise floor.

Note

Time-domain and correlation traces are not affected by rms averaging. In other words, traces that show time-domain data are NOT averaged when rms or rms exponential averaging is selected.

Remember that rms averaging does not eliminate noise, but simply produces an approximation of the actual noise level. Increasing the number of rms averages provides a better statistical approximation of the noise, but does not actually reduce the noise.

With rms averaging, the analyzer takes "N" averages (the number you specify in the "Count" box), then stops. You can then use Restart to repeat the process, or Pause/Single to add another "N" averages to the previous averages.

Hint

For averaging formulas, see online help for the type of measurement data selected. For example, online help for spectrum includes formulas that show how the analyzer creates averaged spectra.

See also

Average Tab

Pausing Averaging

About Averaging


RMS (Video) Exponential Averaging

Menu Path: MeasSetup > Average

Selecting RMS (Video) Exponential as the Averaging type causes the analyzer to perform a RMS (Video) average, but with exponential weighting applied to the data.

For details, refer to

RMS (Video) Averaging)

Exponential Averaging

See also

Average Tab

Pausing Averaging

About Averaging


Time Averaging

(Vector Signal Analyzer application only)

Menu Path: MeasSetup > Average

Unlike other average types, time averaging is done in the time domain, as shown in the following block diagram. Notice that time averaging is performed before the FFT.

Hint

This block diagram is a portion of the Vector and Analog Demodulation block diagrams. Click the following links to see the entire block diagrams:

Vector Analyzer Block Diagram

Analog Demodulation Block Diagram

Note

Time corrections are shown in the previous block diagram for completeness; however, time corrections are not required to perform time averaging.

With time averaging, the analyzer averages "N" time records (where "N" is the number of averages), and then stops. You can then use Restart to repeat the process,.

Although measurements made with time averaging have better signal-to-noise ratios than rms averaging, there are some restrictions:

•	The input signal must be periodic. In other words, the frequency components you want to measure must repeat with each time record. If these components are not periodic (they do not maintain the same phase relationship), their real and imaginary values will cancel and the analyzer will not resolve these components.

•	If you select time averaging, you'll need to provide an external trigger signal. Of course, the analyzer will still make a measurement with free run triggering (no trigger signal), but the amplitude of periodic signals will diminish with each successive average (because even periodic components have random phase with free run triggering).

Hint

For averaging formulas, see online help for the type of measurement data selected. For example, the help topic for the Trace Data menu selection Spectrum includes formulas that show how the analyzer creates averaged spectrums.

Time Averaging and Time Records

With time averaging, the analyzer makes trigger corrections so you can view a stable time record.

With time averaging, real and imaginary components are averaged separately. For example, if the number of averages is 3:

See also

Average Tab

Pausing Averaging

About Averaging


Time Exponential Averaging

(Vector Signal Analyzer application only)

Menu Path: MeasSetup > Average

Selecting Time Exponential as the Averaging type causes the analyzer to perform a time average, but with exponential weighting applied to the data.

For details, refer to Time Averaging and Exponential Averaging .

See also

Average Tab

Pausing Averaging

About Averaging


Count

Menu Path: MeasSetup > Average

Count specifies how many averages to perform.

Suppose you specify 3 averages. For the first average, the analyzer clears previous trace data and obtains a new trace. The second average consists of averaging the next trace with the first trace. The third average consists of averaging the third trace with the averaged results of the first two traces.

The analyzer updates the display after each average. In this example, the analyzer would update the display after the first average, again after the second average, and finally after the third average. To decrease the number of display updates and possibly speed up the measurement, you can turn on Fast Averaging.

See also

Average Tab

Pausing Averaging

About Averaging


Fast Averaging

Menu Path: MeasSetup > Average

When Fast Averaging is on, the analyzer updates the display after the number of averages specified by the Update Rate selection. This may increase measurement speed. For example, if you specify an update rate of 5, the analyzer updates the display after each 5 averages.

You can also select the Same as Count check box to set the update rate to be the same as the average count.

See also

Average Tab

Pausing Averaging

About Averaging


Repeat Averaging

Menu Path: MeasSetup > Average

Repeat averaging only applies to linear (non-exponential and non-peak-hold) averages.

If the average is linear and is selected, the analyzer normally stops after reaching the number of averages you've specified. With repeat averaging on, the analyzer does not stop. Instead, it clears existing data and uses the next trace to start a new average. The analyzer continues this cycle until you turn repeat averaging off, turn averaging off, or click Pause/Single.

For further details, refer to the topics covering sweeping and the Pause/Single control.

See also

Average Tab

Pausing Averaging

About Averaging


Same as Count

Menu Path: MeasSetup > Average

Select the Same as Count check box to set the update rate for fast averaging to the current setting for average count. If you want to set an update rate different from average count, the Same as Count check box must be cleared.

See also

Average Tab

Pausing Averaging

About Averaging


Update Rate

Menu Path: MeasSetup > Average

The setting of Update Rate only affects fast averaging. The number you place in this field determines how often the analyzer updates the display. For example, if you specify an update rate of 5, the analyzer updates the display once every 5 averages. The more often the display updates, the slower the measurement proceeds.

You can use Same as Count to set the update rate to match the average count.

See also

Average Tab

Pausing Averaging

About Averaging


About Frequency

Menu Path: MeasSetup > Frequency

You use parameters on the Frequency tab to set up the frequencies that you are interested in measuring (from the MeasSetup menu, click Frequency).

Depending on whether the Show Center/Span check box is checked or cleared, X-axis annotation is expressed in terms of either:

Center/Span	X-axis is annotated with Center and Span.
or
Start/Stop 	X-axis is annotated with Start and Stop frequencies.

Full span measurements let you view the entire available frequency spectrum on one display. Alternately, you may want to view smaller slices of the frequency spectrum.

You can select any number of different spans and position them by specifying their start and stop frequencies or by specifying a center frequency and span size.

Changing one parameter causes other parameters to change. For example, changing start causes span and center to change. The following table shows how Start, Stop, Center, and Span interact:

If you change...	this does NOT change...	these do  change...
Start	Stop	Span & Center
Stop	Start	Span & Center
Center	Span	Start & Stop
Span	Center	Start & Stop
Note

An exception occurs when changing one parameter would set another to an invalid value. For example, if you change the Center Frequency so that with the current Span the Start Frequency would be less than 0, the analyzer adjusts the Span so that the Start Frequency is valid.

The Show Center/Span check box alternates between the parameters that you can set in the upper two input boxes. When the dialog box first opens, it is ready to receive a center frequency and a span. Clear the Show Center/Span check box to change the input boxes to Start and Stop frequencies.

See also

Changing Frequency Settings


Changing Frequency Settings

You can change the settings for frequency parameters in several ways:

1.	From the Frequency Tab:

a.	Click MeasSetup > Frequency.

b.	If you want to set Center Frequency or Frequency Span, be sure that the Show Center/Span check box is checked. If you want to set Start or Stop Frequency, be sure that the Show Center/Span check box is cleared.

c.	Click the parameter you want to change (for example, Center).

d.	Type the new value and press Enter or click Close.

2.	From the Copy Marker to menu:

Click Markers, Copy Marker to, and the appropriate selection from the menu (Copy Mkr to Center Freq, for example).

3.	From the Trace popup menu

a.	Right-click in the trace.

b.	From the popup menu, click Copy Mkr to Center Freq.

4.	Using the Select Area tool

a.	Click the Area Select tool [image].

b.	Draw a box around the frequency band of interest.

c.	From the popup menu, click the appropriate selection (for example, Frequency Center and Span).


Frequency Bands

Menu Path: MeasSetup > Frequency Bands

Your analyzer may support more than one frequency band. To see the frequency bands supported by your analyzer or to change the Frequency Band, click MeasSetup > Frequency Bands. For example, the 89640 analyzer has two frequency bands: 0 Hz to 36 MHz, and 36 MHz to 2.7 GHz. The 89610 analyzer has only one frequency band: 0 Hz to 40 MHz.

When you change frequency bands, the analyzer changes the frequency settings to their default values for the specified frequency band.

For information on frequency bands for non-VXI measurement hardware, see Set up Other Measurement Hardware for a link to your specific hardware.


Frequency Tab

Menu Path: MeasSetup > Frequency

Use the settings available on this tab for setting up the frequencies that you are interested in measuring. These parameters are available on the Frequency tab:

•	Auto Frequency Step

•	Center Frequency

•	Center Frequency Step Size

•	From Spectrum Analyzer

•	Full Span

•	Mirror Frequency

•	Recording Span

•	Show Center/Span

•	Signal Track

•	Span

•	Start Frequency

•	Stop Frequency

•	Time Data (Baseband or Zoom)


Auto Center Step
Auto Frequency Step

Menu Path: MeasSetup > Frequency

If Auto Frequency Step is checked, the analyzer automatically calculates the most appropriate Center Frequency Step size for the current configuration (1/10 the Frequency Span). This means you cannot specify a Frequency Step. If Auto Frequency Step is cleared, you can specify the step size.


Center Frequency

Menu Path: MeasSetup > Frequency

When you change the center frequency, the analyzer automatically selects Time Data zoom. For information on other ways to set the Center Frequency, see Changing Frequency Settings.

When you change the center frequency, the analyzer changes the start and stop frequencies, but does not change the span. For example, if you look at the following picture, changing the center frequency causes the span to "slide" up or down the x axis.

Display Limits (Trace Blanking)

You can select a center frequency that ranges from the minimum start frequency to the maximum stop frequency. Because of this, it is possible to select a center frequency that causes a negative start frequency. It is also possible to specify a center frequency that causes the stop frequency to exceed the analyzer's frequency range.

If you specify a center frequency that yields a start frequency below the analyzer's frequency range, you won't see anything displayed to the left of the minimum start frequency. For example, if the frequency range of the analyzer is 0 to 39 MHz and you specify a center frequency that yields a negative start frequency, you won't see anything displayed to the left of 0 Hz. This is called Trace Blanking.

Likewise, if you specify a center frequency that yields a stop frequency above the analyzer's frequency range, you won't see anything displayed to the right of the maximum stop frequency. In the previous example, you won't see anything displayed to the right of 39 MHz.

Note

For the 36 MHz to 2.7 GHz frequency band, selecting a center frequency of 36 MHz at full span yields a start frequency of 17.445 MHz and a stop frequency of 54.554 MHz. However, the minimum frequency that the 89640 analyzer can measure is 20 MHz. Therefore, the trace is blank for all frequencies below 20 MHz.

Center frequency limitations with 2-channel I+jQ(Ch1+j*Ch2) input mode

For details about setting the center frequency for I+jQ(Ch1+j*Ch2) mode, see I+jQ Span and Frequency.


Center Frequency Step Size

Menu Path: MeasSetup > Frequency

Changing the value in the Frequency Step input box changes the effect of the arrow keys when you change the center frequency. By default, the center step is set to Automatic, and the arrow keys change the center frequency by steps equal to 1/10 the Frequency Span. When you clear Auto Frequency Step, the value can be edited to any desired frequency.

Note

If you change the frequency step value, then later select Automatic Frequency Step, the step size reverts to the default value, even though the value you previously entered is visible. Its light appearance indicates that it is not the value actually being used.

If Auto Frequency Step is checked, the Frequency Step is unavailable, and the analyzer calculates the best step size for the current configuration.


From Spectrum Analyzer
From Spec Analyzer

(Vector Signal Analyzer application only.)

Menu Path: MeasSetup > Frequency

The From Spec Analyzer button sets the Vector Signal Analyzer application frequency parameters to match those of the Spectrum Analyzer application. It also transfers the following settings from the Spectrum Analyzer:

•	RBW

•	Window

•	Input Range

•	Input Coupling

•	All trigger parameters

This is useful when you're running both applications at the same time. For example, you may want to use the Spectrum Analyzer application to locate a signal over a wide frequency range and use the Vector Signal Analyzer application to demodulate the signal. In this case, launch both applications, locate your signal with the Spectrum Analyzer application, then click From Spec Analyzer to quickly configure the Vector Signal Analyzer application to measure that signal.


Full Span

Menu Path: MeasSetup > Frequency

Click Full Span to set the span to its maximum. The maximum span depends on the ADC module or modules in your analyzer and varies for Spectrum Analyzer and Vector Signal Analyzer.

When you are playing back a recording, the name of this button changes to Recording Span, and its function is different.


Mirror Frequency

Menu Path: MeasSetup > Frequency tab > Mirror Frequency check box

Default: cleared

Use Mirror Frequency if you are measuring a signal that is mirrored and you want to display the signal unmirrored.

Selected:  The displayed frequency spectrum is mirrored (flipped) about the analyzer center frequency.

Cleared:  Does not mirror the frequency spectrum.

Note

This feature is available only for zoomed measurements, not for baseband.

External down converter

If you are using an external down converter, clear this Mirror Frequency check box and use the Mirror Frequency parameter in the External Frequency Calibration dialog box instead.

Digital demodulated signals

If you are using Digital Demodulation (Digital Demodulator is selected), use this parameter to correctly demodulate and display mirrored spectrums instead of the Digital Demodulation Properties Mirror Frequency Spectrum check box.

Mirror frequency concepts

Often, when a signal is mixed down from a higher frequency, the spectrum is flipped or mirrored about the center frequency as a result of the mixing scheme used. A mirrored spectrum occurs when the frequency of the mixer's LO is higher than the frequency of the signal being measured.

Many RF and microwave spectrum analyzers perform their first frequency conversion in bands. The mixing scheme for each band may be different--the spectrum may be mirrored in some bands but not in others.

To get the correct display of a flipped spectrum, select the Mirror Frequency check box.

See also

Mirror Frequency Spectrum (Digital Demodulation)

Mirror Frequency (External Frequency Calibration)


Recording Span

Menu Path: MeasSetup > Frequency

When you click Recording Span, the Frequency Span gets set to match the span that was used when the recording was taken.

When the analyzer is playing back a recording, the name of this button is Full Span, and its function is different.


Show Center/Span

Menu Path: MeasSetup > Frequency

When the Show Center/Span check box is checked, the trace display shows the Center Frequency and Frequency Span. When the check box is cleared, the trace display shows Start Frequency and Stop Frequency.

Note

The Show Center/Span check box is linked to the Show Center/Span on all Traces check box in the X Scale dialog box. When you select or clear either box, the other box also gets checked or cleared.


Signal Track

Menu Path: MeasSetup > Frequency

The analyzer can change its center frequency automatically to track an input channel's drifting signal. The Signal Track check box enables and disables this feature. For a 2-channel analyzer, you can specify whether to track the signal on Channel 1 or Channel 2.

Tip

You can achieve better results if you use a window with good frequency characteristics, such as a Gaussian or Hanning window, in that order.

When signal tracking is enabled, the analyzer adjusts the value of Center frequency to keep the largest signal centered in the current frequency span. The effect of signal tracking is similar to the effect you would get by continuously clicking the following sequence: Right click in trace, ↑ Peak, Right click in trace, Copy Mkr to Center Freq.

If you change the Center Frequency, Signal Track turns off.

In some cases, Signal Track is on, but the analyzer cannot set the center frequency to the correct value. This happens when the frequency span is set to Full Span and you turn on signal tracking. Signal Track cannot change the span, and the analyzer is limited in where it can set the center frequency.

Signal tracking is unavailable for some configurations, as shown below.

With this configuration:	You can signal track on this channel:
	Channel 1	Channel 2
Digital Demodulation	No	No
Averaging ON	No	No
Any other configuration	Yes	Yes


Span

Menu Path: MeasSetup > Frequency

The frequency span sets the width of the frequency band that you want to analyze. For information on other ways to set the Frequency Span, see Changing Frequency Settings.

To determine available settings for frequency span, click the Span hotspot on the display and use the keyboard up/down arrow keys or the mouse wheel to scroll through the available settings.

Hint

To quickly set span to its maximum value, click Full Span. To quickly go from Full Span to a narrower span, use the Select Area tool to outline the area of interest on the trace. Then select Frequency Span from the popup menu.

Interaction With Other Parameters

When you change the span, the analyzer changes the start and stop frequencies, but does not change the center frequency. For example, in the picture below, changing the span causes the span to "expand" or "contract" around the center frequency.

Note

When using the Spectrum Analyzer application, the center frequency does change if a change in frequency span exceeds the lower or upper frequency limit.

Maximum Span

The maximum span that you can enter depends on the Input channel and instrument mode. The best way to determine the maximum span for your hardware is to click the Full Span button.

Span limitations with ADS connectivity

When you are using the 89600 with Agilent ADS simulations, the maximum span is limited by the sample rate of the data coming in.

The minimum span is limited by several factors.

1.	The maximum decimation that can be applied is 256, so this places a limit of .001525878906 (1/256 times 1/2.56) times the sample rate (1/Tstep) for Float inputs. For Complex inputs, the limit is .000762939453.

2.	For larger decimated time records, the size of the undecimated time record can exceed memory limitations and the ability of the simulation to produce data.

3.	Annotation can drop below readable limits when the span becomes extraordinarily low.

Span limitations when playing back a recording

When you are playing back a recording, the maximum span cannot be greater than the span used when the data was recorded. You can set a minimum span of 1/256 times the span used when the data was recorded.

If you play back the recording that is too short to support the specified span, you see a message saying "The recording is not long enough for the current measurement." You can either take a longer recording or decrease the measurement span.

Span limitations with digital demodulation

When you play back a recording with digital demodulation on, the span is limited by the maximum points per symbol value of 20. If you specify a span that requires more the 20 points per symbol, the analyzer adjusts the span downward to a valid setting.

Span limitations with 2-channel I+jQ(Ch1+j*Ch2) input mode

For details about span limitations when using dual channel I+jQ(Ch1+j*Ch2) input mode, see I+jQ Span and Frequency.


Start Frequency

Menu Path: MeasSetup > Frequency

The Start Frequency sets the start (lowest) frequency of the frequency band you want to analyze. For information on other ways to set the Start Frequency, see Changing Frequency Settings.

The following picture shows start frequency as compared to the other frequency parameters:

When you change the start frequency, the analyzer changes the span and center frequencies, but does not change the stop frequency, except in these two cases:

1.	If you specify a start frequency that yields an invalid span, the analyzer changes the stop frequency to maintain a valid span.

2.	If you specify a start frequency greater than the stop frequency, the analyzer changes frequencies to achieve the minimum valid span. The width of the span varies for the Spectrum Analyzer and Vector Signal Analyzer.

Display Limits (Trace Blanking)

It is possible to select a negative start frequency. It is also possible to specify a start frequency that causes the stop frequency to exceed the analyzer's frequency range. If you specify a negative start frequency, you won't see anything displayed to the left of 0 Hz (the analyzer does not display frequency data less than 0 Hz.) If you specify a start frequency such that the stop frequency exceeds the analyzer's frequency range, you won't see anything displayed to the right of the maximum stop frequency. This is called Trace Blanking.

Note

For the 36 MHz to 2.7 GHz frequency band, you can select a start frequency of 17.445 MHz for full span measurements. Because the minimum frequency that the 89640 analyzer can measure is 20 MHz, the trace is blank for all frequencies below 20 MHz.

Start frequency limitations with 2-channel I+jQ(Ch1+j*Ch2) input mode

For information about span and frequency when using dual channel I+jQ(Ch1+j*Ch2) input mode, see I+jQ Span and Frequency.


Stop Frequency

Menu Path: MeasSetup > Frequency

The stop frequency is the end (highest) frequency of the frequency band you want to analyze. For information on other ways to set the Start Frequency, see Changing Frequency Settings.

Note

The maximum stop frequency that the analyzer can measure is determined by the selected ADC. For details, see online help for ADC.

The following picture shows stop frequency as compared to the other frequency parameters:

When you change the stop frequency, the analyzer changes the span and center frequencies, but does not change the start frequency, except in these two cases:

1.	If you specify a stop frequency that yields an invalid span, the analyzer changes the start frequency to maintain a valid span.

2.	If you specify a stop frequency less than the start frequency, the analyzer changes the start frequency to achieve a valid minimum span. The width of the span varies for Spectrum Analyzer and Vector Signal Analyzer.

Display Limits for (Trace Blanking)

It is possible to select a stop frequency that results in a negative start frequency. It is also possible to specify a stop frequency that exceeds the analyzer's frequency range.

If you specify a stop frequency that results in a negative start frequency, you won't see anything displayed to the left of 0 Hz (the analyzer does not display frequency data less than 0 Hz.) This is called Trace Blanking.

If you specify a stop frequency that exceeds the analyzer's frequency range, you won't see anything displayed to the right of the maximum stop frequency. This is called Trace Blanking.

Start frequency limitations with 2-channel I+jQ(Ch1+j*Ch2) input mode

For information about span and frequency when using dual channel I+jQ(Ch1+j*Ch2) input mode, see I+jQ Span and Frequency.


Time Data

(Vector Signal Analyzer application only.)

Menu Path: MeasSetup > Frequency

The Time Data box lets you enable or disable the analyzer's digital LO (local oscillator) when the start frequency is 0 Hertz. The default is disabled (baseband).

Note

This feature is unavailable for these kinds of measurements: Analog or Digital Demodulation, and Spectrum Analyzer.

The feature is also unavailable if the Frequency Band start frequency is greater than 0. For these configurations, time data is always zoomed (the analyzer's digital LO is always on).

If the feature is available, and you select Zoom, the analyzer turns on its digital LO. If you select baseband, the analyzer sets the start frequency to 0 Hertz and turns off its digital LO.

Note

Time Data automatically toggles to Zoom if the Start frequency is non-zero.

Baseband versus Zoom

The term "baseband" identifies a measurement that has real time-domain data. In baseband mode the signal is analyzed from 0 Hz to the highest frequency of interest. The term "zoom" identifies a measurement that has complex time-domain data. In zoomed mode the signal is analyzed within a specified bandwidth, usually centered on the frequency of interest. Zoomed measurements can start at 0 Hz or other frequencies.

The analyzer performs "zoomed" measurements using an internal digital LO (local oscillator). The measurement is "baseband" when the digital LO is off. In this case the input signal is not mixed with the analyzer's LO, and the time-domain data is real.

The measurement is "zoomed" when the digital LO is on. In this case, the input signal is mixed with the analyzer's digital LO, and the resulting time-domain data is complex--it contains both a real and an imaginary component.

Normally, when making vector measurements, the digital LO is off when the start frequency is 0 Hertz, and it is on when the start frequency is NOT 0 Hertz. The Time Data button lets you turn on the digital LO when the start frequency is 0 Hertz and the Frequency Band starts at 0 Hz.


About Selecting Hardware

Menu Path: Utilities > Hardware

The Select Hardware dialog box lists the available hardware, identifies the currently used hardware, and lets you select the hardware that you want to use when making a measurement.

If you connect new hardware to your analyzer while 89600 software is running, you must close and restart all 89600 software before the analyzer will recognize the new hardware.

Note

If your analyzer uses a standard configuration, the analyzer automatically sets up the hardware when you start the Vector Signal Analyzer or Spectrum Analyzer application. You should not need to use this dialog box unless you want to change the configuration or use a non-standard VXI module configuration. To learn what configurations are standard, see Supported Hardware Configurations.

	Next to the name on each tab you will see either a green select mark or a red X. These icons indicate whether the module selected on each tab are valid in combination with modules selected on other tabs. The modules are evaluated in order from left to right. The green checkmark means that the module currently selected on that tab is valid in combination with modules selected on tabs to the left. A red X means that the module currently selected on that tab is not valid in combination with modules selected on tabs to the left.
Information in the Select Hardware Dialog Box

When the analyzer application starts, it retrieves supported hardware information from the resource manager table and determines what the installed hardware configuration is. The Select Hardware dialog box displays this information. The devices are grouped and listed by their hardware type, as indicated by the tab header. The information is tailored to the specific device and includes address, location, and name (or description).

	RESOURCE INFORMATION
Hardware type	Address	Location	Name
VXI hardware	VXI mainframe and module logical address	VXI slot number	Description
Simulated hardware	SIM::model number	—	Description
89601 opt 105	USR: Stream	—	Description
Other measurement hardware	GPIB address or LAN information	—	Description
Source hardware	GPIB address	—	Description

The Info. button opens a window that can display more information about the checked device including: serial number, driver revision, and/or firmware revision.

Selecting Hardware

The Select Hardware dialog box lets you custom select hardware from the displayed list of Supported Hardware . To select a specific device you just click its check box.

Notes

•	The software will not allow you to specify an unsupported hardware configuration. The OK button is greyed until you specify a supported configuration.

•	You cannot change instrument addresses or names from this dialog box.

When you start the Vector Signal Analyzer or Spectrum Analyzer application, the application scans for connected hardware and then identifies them with a checkmark.

If the hardware is not turned on, or is not connected to the computer, the analyzer will not find it and list it. If your hardware is not listed and you want it to be, do the following:

1.	Exit the analyzer application.

2.	Make sure that the hardware has the correct address.

3.	Make sure that the interconnect cables are properly attached.

4.	Make sure that the hardware is turned ON.

5.	Run VISA assistant to make sure that the computer is able to locate the hardware.

6.	Restart the analyzer application.

The list of available hardware is read-only, and is generated by the application during power up. You can specify which hardware devices to include, but you cannot change the addresses or instrument names from this dialog box. If you want to change a device address, you must change it at the device. (For VXI hardware see "Set logical addresses" in the Hardware Installation chapter of the Installation and Service Guide.)

You can also choose to simulate the hardware or, if your analyzer includes option 105, you can select the stream interface.

If the Simulate Hardware check box is checked, all modules must be simulated. You cannot specify a mixture of simulated and actual modules.

If Default Configuration is checked, the analyzer chooses all modules for you. If both Default Configuration and Simulate Hardware are checked, the analyzer chooses the most appropriate combination of simulated modules. If Default Configuration is checked and Simulate Hardware is cleared, the analyzer chooses the most appropriate configuration for the available hardware.

Remember that you must select a valid supported hardware configuration or the 89600 software returns an error message.

Note

Preset does not affect the hardware configuration.

See also

Supported Hardware Configurations

Default Configuration check box

Simulate Hardware check box

Save Selection check box

Configure Button

ADC tab

Down Converter tab

Input Module tab

Source Tab


Supported Hardware Configurations

The following tables show the measurement hardware configurations and sources supported by the 89600 software.

The Agilent 89600 Series VSA Configuration Guide lists supported hardware, including required option and firmware revision information. You can find the guide in these two places:

•	As a PDF file on the 89600 Installation CD, in the prodinfo directory.

•	As a download from the 89600 VSA web site. To access the web site now, click here.

Some hardware configurations are not supported.

	Next to the name on each tab you will see either a green select mark or a red X. These icons indicate whether the module selected on each tab are valid in combination with modules selected on other tabs. The modules are evaluated in order from left to right. The green checkmark means that the module currently selected on that tab is valid in combination with modules selected on tabs to the left. A red X means that the module currently selected on that tab is not valid in combination with modules selected on tabs to the left.
The 89600 software supports the measurement hardware combinations listed in the following tables. The first table lists configurations for the Vector Signal Analyzer application; the second table lists configurations for the Spectrum Analyzer application. Each column in the tables lists the hardware available on that tab. Each row lists the hardware combinations that are supported for each ADC1 selection.

Note

If you are using VXI measurement hardware, you must specify ADC1 and an Input Module. For some VXI hardware configurations, you also must specify ADC2 and a Down Converter. For other measurement hardware, you only specify ADC1 for a single-channel system, and ADC1 and ADC2 for a 2-channel system.

Vector Signal Analyzer application Hardware Combinations

ADC 1	ADC 2	Down Converter	Input Module	Source
E1439	None or E1439	E2730 (Ch1 only), E2371 (Ch1 only), PSA, or none	89605	None or ESG OR PSG‡
E1438	None or E1438	None	89606	None or  ESG OR PSG‡
E4406	None or E4406	None	None	None or ESG OR PSG‡
PSA	None or PSA	None	None	None or ESG OR PSG‡
ESA	None or ESA	None	None	None or ESG OR PSG‡
Infiniium Oscilloscope	None	None	None	None or ESG OR PSG‡
Stream†	None or Stream†	None	None	None or  ESG OR PSG‡
† Stream is available only for the ADS Interface (option 105) and does not represent actual hardware.

‡ All E4438C (with option 001 or 002), E8267C (with option 001 or 002), ESG-D (with option UND), and ESG-DP (with option UND) sources are supported.

Spectrum Analyzer application Hardware Combinations

ADC 1	ADC 2	Down Converter	Input Module	Source
E1439	None	E2730, PSA, or none	89605	None
E1438	None or E1438	None	89606	None
† Stream is available only for the ADS Interface (option 105) and does not represent actual hardware.


ADC Tab (Select Hardware)

Menu Path: Utilities > Hardware

On the ADC 1 and ADC 2 tabs, you specify the ADC hardware for channel 1 and, for a 2-channel VXI analyzer, the ADC module for channel 2. The table lists all the connected and configured hardware that can serve as Analog-to-Digital Converters. The list also includes "Stream" if your analyzer includes option 105 software (ADS interface). You can select any of the listed devices for ADC 1. ADC2 must be the same model as ADC 1. If the selected hardware has any configuration options, the Configure button becomes available. Clicking it opens an editing dialog box, allowing you to select from the available configuration options.

Note

For VXI measurement hardware, you must connect the 10 MHz Ref Out from the Input Module to the Ext Clock/Ref connector on the module you specify as ADC 1.

Some hardware configurations are not supported. For a list of supported configurations, see Supported Hardware Configurations.

	Next to the ADC on the tab you will see either a green select mark or a red X. These icons indicate whether the module selected on each tab are valid in combination with modules selected on other tabs. The modules are evaluated in order from left to right. The green checkmark means that the module currently selected on that tab is valid in combination with modules selected on tabs to the left. A red X means that the module currently selected on that tab is not valid in combination with modules selected on tabs to the left.
If the Simulate Hardware check box is checked, all modules must be simulated. You cannot specify a mixture of simulated and actual modules.

If Default Configuration is checked, the analyzer chooses all modules for you. If both Default Configuration and Simulate Hardware are checked, the analyzer chooses the most appropriate combination of simulated modules. If Default Configuration is checked and Simulate Hardware is cleared, the analyzer chooses the most appropriate configuration for the available hardware.

See also

About Selecting Hardware


Down Converter Tab (Select Hardware)

Menu Path: Utilities > Hardware

The Down Converter 1 and 2 tabs on the Hardware dialog box list all the supported devices that can serve as an integrated RF Converter. You can select any of the listed devices. If the selected module has any configuration options, the Configure button becomes available. Clicking it causes an editing dialog box to open allowing you to select from the available configuration options.

Some hardware configurations are not supported. For a list of supported configurations, see Supported Hardware Configurations.

	On the Down Converter tab you will see either a green select mark or a red X. These icons indicate whether the module selected on each tab are valid in combination with modules selected on other tabs. The modules are evaluated in order from left to right. The green checkmark means that the module currently selected on that tab is valid in combination with modules selected on tabs to the left. A red X means that the module currently selected on that tab is not valid in combination with modules selected on tabs to the left.
If the Simulate Hardware check box is checked, all hardware must be simulated. You cannot specify a mixture of simulated and actual hardware.

If Default Configuration is checked, the analyzer chooses all modules for you. If both Default Configuration and Simulate Hardware are checked, the analyzer chooses the most appropriate combination of simulated modules. If Default Configuration is checked and Simulate Hardware is cleared, the analyzer chooses the most appropriate configuration for the available hardware.

See also

About Selecting Hardware


Input Module Tab (Select Hardware)

Menu Path: Utilities > Hardware

The Input Module 1 and 2 tabs on the Hardware dialog box list all the modules located in the VXI mainframe that can serve as the Input Module. You can select any of the listed devices. If the selected module has any configuration options, the Configure button becomes available. Clicking it causes an editing dialog box to open allowing you to select from the available configuration options.

If you are using an 89605B or an 89606B input module, click Configure to specify either a 10 MHz or 13 MHz external reference frequency.

Some hardware configurations are not supported. For a list of supported configurations, see Supported Hardware Configurations.

	On the Input Module tab you will see either a green select mark or a red X . These icons indicate whether the module selected on each tab are valid in combination with modules selected on other tabs. The modules are evaluated in order from left to right. The green checkmark means that the module currently selected on that tab is valid in combination with modules selected on tabs to the left. A red X means that the module currently selected on that tab is not valid in combination with modules selected on tabs to the left.
If the Simulate Hardware check box is checked, all modules must be simulated. You cannot specify a mixture of simulated and actual modules.

If Default Configuration is checked, the analyzer chooses all modules for you. If both Default Configuration and Simulate Hardware are checked, the analyzer chooses the most appropriate combination of simulated modules. If Default Configuration is checked and Simulate Hardware is cleared, the analyzer chooses the most appropriate configuration for the available hardware.

See also

About Selecting Hardware


Source Select Tab (Select Hardware)
Source Tab (Select Hardware)

(Vector Signal Analyzer application only.)

Menu Path: Utilities > Hardware

The Source tab lists all the supported signal sources. You can select any of the listed devices.

Some hardware configurations are not supported. For a list of supported configurations, see Supported Hardware Configurations.

	On the Source tab you will see either a green select mark or a red X . These icons indicate whether the module selected on each tab are valid in combination with modules selected on other tabs. The modules are evaluated in order from left to right. The green checkmark means that the module currently selected on that tab is valid in combination with modules selected on tabs to the left. A red X means that the module currently selected on that tab is not valid in combination with modules selected on tabs to the left.
If the Simulate Hardware check box is checked, all modules must be simulated. You cannot specify a mixture of simulated and actual modules.

If Default Configuration is checked, the analyzer chooses all modules for you. If both Default Configuration and Simulate Hardware are checked, the analyzer chooses the most appropriate combination of simulated modules. If Default Configuration is checked and Simulate Hardware is cleared, the analyzer chooses the most appropriate configuration for the available hardware.

See also

About Selecting Hardware

About Source


Configure (Select Hardware)

Menu Path: Utilities > Hardware > Configure

The Configure button displays a dialog box that lets you modify parameters for the selected hardware. You can change a parameter by clicking the parameter name and the Edit button. For True/False values, a select in the check box sets the value to True. An cleared check box sets the value to False.

To return a parameter to its default value, click the Default button.

E1439 ADC, E1438 ADC, and E2730/E2731 RF Tuner modules

Parameter	Value	Default
Lock Reference	True/False	True
Non-VXI measurement hardware

For information on Configure for non-VXI measurement hardware, see Configure other Measurement Hardware for a link to your specific hardware.

Lock Reference

If Lock Reference is true, the module uses the signal at the Ext Ref connector on its front panel as the frequency reference. For 89600 analyzers with VXI measurement hardware, this means that all modules are referenced to the 10 MHz Ref output of the 89605 or 89606 module.

If Lock Reference is false, the module references to its internal clock.

See also

About Selecting Hardware


Default Configuration (Select Hardware)

Menu Path: Utilities > Hardware

When the Default Configuration check box is checked, the analyzer scans the modules in the VXI mainframe or other supported hardware connected to your PC and automatically sets up the configuration that makes the most sense for the 89600 analyzer. For example, if your VXI mainframe includes an 89606 module and two E1438 modules, the default configuration selects E1438 for ADC1 and ADC2, and 89606 for the Input Module. Or if your mainframe includes 89605, E2730, and E1439 modules, the default configuration selects E1439 for ADC 1, E2730 for Down Converter, and 89605 for Input Module.

If Simulate Hardware is also checked, the analyzer chooses the most appropriate combination of simulated hardware modules.


Info (Select Hardware)

Menu Path: Utilities > Hardware > Info…

Clicking this button opens an information dialog box listing the serial number, driver revision, and firmware revision for the checked module on the Select Hardware tab. For example, on the Input Module tab, if the 89605 module is checked, the Information dialog box lists information for the 89605 input module.

See also

About Selecting Hardware


Save Selection (Select Hardware)

Menu Path: Utilities > Hardware

When the Save Selection check box is checked, the current hardware setup is saved when you close the analyzer and will be assigned when you restart the analyzer.

When the Save Selection check box is cleared, the current hardware setup is not saved, and will not be recalled when you restart the analyzer.

See also

About Selecting Hardware


Simulate Hardware (Select Hardware)

Menu Path: Utilities > Hardware

When the Simulate Hardware check box is checked, you can use the analyzer without VXI measurement hardware. In this mode, you cannot input data from VXI hardware. You can recall traces or time captures, or you can replay recorded data.

When Simulate Hardware is on, each of the module tabs in the Select Hardware dialog box list the modules that can be simulated. For example, the ADC tabs may list SIM::E1438 and SIM::E1439. The analyzer supports the same hardware configurations for simulated hardware as for regular VXI hardware. For a list of supported configurations, see Supported Hardware Configurations.

See also

About Selecting Hardware


Reference Frequency

Menu Path: Utilities > Reference Frequency

Use this dialog box to set up the reference frequency, specifying the following:

•	whether the system should lock to the System Reference Master's internal clock or an external reference (System Reference Source)

•	which module the reference signal is connected to (System Reference Master)

•	the frequency of the external reference signal (Ext Reference Frequency)

The dialog box also lists the current status of the system reference and provides access to details about the system reference.

Note that the settings in this dialog box are not affected by Preset or Save/Recall.


Current Status (Reference Frequency)

Menu Path: Utilities > Reference Frequency

The information listed in this area is the same as that in the External Reference Lock State area of the display.


Details (Reference Frequency)

Menu Path: Utilities > Reference Frequency

Click Details to open the Reference Details dialog box, listing the external reference state for each module. The state includes the presence or absence of an external reference signal and whether the module is locked to that signal.

A red x ( [image] ) next to a module indicates that module is not properly configured and locked. In this case, the measurement hardware is not all referenced to the same frequency source. To change the configuration or lock status, click the Configure button in the corresponding tab in the Select Hardware dialog box.

See also

Reference Frequency dialog box

System Reference Source

System Reference Master

Ext Reference Frequency


Ext Reference Frequency

Menu Path: Utilities > Reference Frequency

In the Ext Reference Frequency text box you can specify the frequency of the external reference signal. Valid entries depend on which piece of hardware you are connecting the reference signal to. For example, the 89605B and 89606B modules will accept only 10 MHz or 13 MHz signals, while the E4406 will accept any signal between 1 MHz and 30 MHz.

When you change the System Reference Master, the analyzer resets the Ext Reference Frequency to 10 MHz for all other measurement hardware.

See also

Reference Frequency dialog box

System Reference Source

System Reference Master

Details


System Reference Master

Menu Path: Utilities > Reference Frequency

The System Reference Master box lists the hardware to which you connected the external reference signal. Select from the list to specify which hardware you want to use as the system reference.

See also

Reference Frequency dialog box

System Reference Source

Ext Reference Frequency Details


System Reference Source

Menu Path: Utilities > Reference Frequency

Use the System Reference Source radio buttons to specify whether the measurement hardware should lock to its internal clock or to the signal at the Ext Ref In connector of the Reference Master.

If the Ext is selected, the hardware uses the signal at the Ext Ref In connector as the frequency reference.

If the Int selected, that hardware uses its internal clock as the frequency reference.

If the hardware does not have an Ext Ref In connection, the System Reference Source is automatically set to Internal, the radio buttons are greyed, and you cannot specify External.

Note

If your VXI measurement hardware includes an 89605B or an 89606B module, the system reference source automatically changes between External and Internal when you connect or disconnect a signal at the Ext Ref In connector. The radio buttons are greyed, and you cannot change the setting.

See also

Reference Frequency dialog box

System Reference Master

Ext Reference Frequency Details


About Markers

The 89600 analyzer includes several markers and marker functions that you access from the Markers menu.

The variety of markers, ease of use, and flexibility are key attributes of the 89600 analyzer markers. You can quickly set the marker location, manually position them, locate peak values, and couple the markers between traces to show common values.

Marker calculation features allow you to easily calculate band power,. RMS band power, and channel-to-noise power.

Each trace has its own marker and offset marker. The marker indicates the x-axis and y-axis position for any point on a trace. The offset marker indicates the relative value between the marker and offset marker.

	The marker appears as a diamond on the trace; the offset marker appears as a square. This illustration shows a marker on the right and offset marker on the left.
For some OFDM data, the analyzer also displays a z-axis component (see OFDM markers).

When a marker is on, the analyzer displays marker readouts just below the traces. The marker readouts reflect the marker values for the identified marker location.

For spectrogram displays, the regular marker displays the time for the current trace and the x-axis and y-axis values for the marker position in the current trace. You can use a Trace Select marker to specify the current trace from the spectrogram.

Tip

You can use the mouse and keyboard shortcuts to quickly perform some marker operations. See Marker shortcuts for details.

The Markers menu lets you perform the following marker functions:

•	Position. Turn on and position a marker and an offset marker, turn on and off peak tracking and marker coupling.

•	Calculation. Set up band power markers, specify what a value to be calculated, and turn the frequency counter on or off.

•	Spectrogram Set up spectrogram markers.

•	Search. Move the marker to a specific x-axis (and z-axis) location.

•	Copy Marker to. Quickly set the value for many parameters to the current marker value.

•	Tools. Choose from marker tools (duplicate of the marker tools toolbar).

•	Show Marker. Turn the marker on or off.

•	Couple Markers

•	Show Offset Turn the offset marker on or off.

See also

Marker Shortcuts

OFDM Markers

Spectrogram Markers


Spectrum Analyzer Markers

Markers behave a little differently in the Spectrum Analyzer application than they do in the Vector Signal Analyzer application.

For each frequency point in a Spectrum Analyzer trace, there are two Y-axis values—the minimum and maximum values for that point. When you use the keyboard arrow keys or the mouse wheel to move the marker across a Spectrum Analyzer display, the marker readout displays first the minimum, then the maximum value for the point. The readout specifies "Max" or Min". You must press the arrow key twice or turn the mouse wheel two clicks to move from one frequency point to the next. The following screens show the minimum and maximum values for one frequency point.


Marker Shortcuts

You can use the Markers menu to set up and move markers, but it might be easier to use some of the keyboard and mouse shortcuts or marker tools.

Mouse shortcuts

•	Click on the marker tool icon of interest from the Markers Toolbar menu (Select Area tool [image], Marker tool [image], Band Power tool [image], Time Gate tool [image]), then click in the trace to place the marker.

•	Right-click in the trace and click Show Marker, Show Offset, or Show Band Power.

•	If more than one marker is turned on in a trace, click the marker tool to activate the marker you want to move.

•	Drag the marker, or just click where you want the marker to move.

•	Shift-drag the offset marker.

•	Marker to peak: right-click in trace, click ↑ Peak.

•	If band power markers are active, drag the center and width. Shift-drag the center and left or right. Click, and the band center moves to that location.

•	Double click or right click the marker readout x-position (or z-position), select Edit and enter the marker position. You can also point to the readout and use the keyboard arrow keys or the mouse wheel to change the value and move the marker.

Keyboard shortcuts

The following shortcuts all refer to marker search functions.

Note

These shortcuts behave differently for OFDM markers.

•	Home moves the marker to the first point.

•	End moves the marker to the last point.

•	Page Up moves the marker to peak.

•	Page Down moves the marker to minimum.

•	← moves the marker one point to the left. For Spectrum Analyzer results, there are two values at each frequency point: the minimum and maximum for the point. As you use the left arrow key to move the marker, the marker area shows first the maximum then the minimum value for each point.

•	→ moves the marker one point to the right. For Spectrum Analyzer results, there are two values at each frequency point: the minimum and maximum for the point. As you use the right arrow key to move the marker, the marker area shows first the minimum then the maximum value for each point.

•	↑ moves the marker to the next larger peak.

•	↓ moves the marker to the next smaller peak.

•	Ctrl + ← moves the marker to next peak to the left.

•	Ctrl + → moves the marker to next peak to the right.


Marker Readouts

The analyzer displays marker values just below the traces. The displayed trace data determines the assigned measurement results.

Notes

With the Spectrum Analyzer Application, there are two marker values for each frequency point. For details, see Spectrum Analyzer Markers .

For information on marker readouts with spectrogram markers, see About Spectrogram Markers. .

The label preceding the marker value indicates how the marker value was derived:

•	Marker means the marker values are absolute. The marker values shown are the x-axis and y-axis values of the marker.

•	Offset means the marker values are relative. The marker values shown are the difference between the offset marker and the marker (marker value minus offset marker value). For Log Mag or Linear Magnitude trace formats, the offset marker shows the ratio between the marker and the offset marker (marker value divided by offset marker value).

•	Freq is displayed when the frequency counter is enabled. The marker values shown are from the frequency counter.

•	Power means the value is a band power calculation.

•	RMS means the value is an RMS Sqrt (Pwr) calculation.

•	C/N means the value is a carrier-to-noise ratio calculation.

•	C/No means the value is a carrier-to-noise density calculation.

•	NAN (Not A Number) is displayed when the marker value is invalid (for example, if the marker value is the result of a math function that divides by zero).

•	INF (Infinity) is displayed when the marker value exceeds approximately 3.4E+38.

Polar Display Marker Readouts

The Polar Format box in the Position tab of the Markers Properties dialog box determines the readout for a polar display. You can choose between Mag & Phase and Real & Imag. The default is Mag & Phase.


Marker Searches
Marker Search Operations

Menu Path: Markers > Search

Marker search operations let you quickly move the marker to specific points on the active trace. Selecting from this menu enables a marker for the active trace if one is not already enabled.

Note

Marker search operations behave differently for OFDM measurements.

You can also move the marker to a target value by editing the Marker Position display annotation below the trace. The target value is always absolute, even when the offset marker is on. The marker will always move to the value you enter.

Note

The "next peak" must be at least one display point away from the marker's current location. If the analyzer doesn't find a peak, the marker doesn't move.

Generally, the best way to change the number of peaks found is to average several measurements to reduce noise variance.

Available Marker Search menu operations:

•	 Peak

•	 Peak Lower

•	 Peak Higher

•	 Peak Right

•	 Peak Left

•	 Minimum

 Peak

Select Peak to move the marker to the highest point on the active trace.

(Shortcuts: press the Page Up key, or right-click in the trace and select↑ Peak from the menu.)

•	The highest point is the point with the largest y-axis value.

•	If the polar (IQ) data format is selected, the highest point is the point with the largest magnitude.

The analyzer can automatically move the marker to the highest point each time the active trace is updated. To enable this feature (called peak tracking), select the Peak Track check box in the Markers Position dialog box.

 Peak Lower

Select Peak Lower to move the marker to the next lower peak on the active trace. The analyzer goes through the whole trace and analyzes all peaks, then moves the marker to the peak with the next lower value compared to the current marker value.

(keyboard shortcut: ↓)

Note

With the polar (IQ) data format, Peak Lower moves the marker to the closest point that has a lower magnitude than the marker's current position.

 Peak Higher

 Select Peak Higher to move the marker to the next higher peak on the active trace. The analyzer goes through the whole trace and analyzes all peaks, then moves the marker to the peak with the next higher value compared to the current marker value.

(keyboard shortcut: ↑)

Note

With the polar (IQ) data format, Peak Higher moves the marker to the closest point that has a higher magnitude than the marker's current position.

 Peak Right

Select Peak Right to move the marker right, to the next valid peak. (A valid peak is one for which the Y-axis value on either side drops at least 4% of the Y-axis height before the values begin rising again.). This function is useful if the marker is close to a peak and you want to fine-tune the marker position to the peak.

(keyboard shortcut: Ctrl + →)

Note

If the polar (IQ) data format is selected, the next peak is the next point (forward in time) with a higher magnitude.

 Peak Left

Select Peak Left to move the marker left, to the valid next peak. . (A valid peak is one for which the Y-axis value on either side drops at least 4% of the Y-axis height before the values begin rising again.). This function is useful if the marker is close to a peak and you want to fine-tune the marker position to the peak.

(keyboard shortcut: Ctrl + ←)

Note

If the polar (IQ) data format is selected, the next peak left is the previous point (back in time) with a higher magnitude.

 Minimum

Select Minimum to move the marker to the lowest point on the active trace. The lowest point is the point with the smallest y-axis value.

(keyboard shortcut: Page Down)

Note

If the polar (IQ) data format is selected, the lowest point is the point with the smallest magnitude.


Copying Markers to Set Parameters

Menu Path: Markers > Copy Marker to

The Marker menu's Copy Marker to item lets you quickly set some measurement parameters to the marker value. If the marker value is outside the valid range for a parameter, the analyzer uses the closest valid setting.

•	Copy Marker to Start Freq sets the measurement start frequency to the marker frequency.

•	Copy Marker to Stop Freq sets the measurement stop frequency to the marker frequency.

•	Copy Marker to Center Freq sets the measurement center frequency to the marker frequency.

•	Copy Marker to Ref Level sets the Y-axis reference level to the amplitude at the marker.

•	Copy Marker to Despread Chan sets the Despread Channel (code and layer) parameters for 3G Cellular demodulation format measurements to the marker value (including W-CDMA, cdma2000, TD-SCDMA and 1xEV-DO).

•	Copy Marker to Analysis TS/SF sets the analysis timeslot and sub-frame for TD-SCDMA demodulation measurements to the marker value.

•	Move Offset to Mkr sets an offset marker at the marker position.

•	Copy Offset to Span Freq sets the measurement frequency span to the marker offset value (the difference between the marker and the offset marker.

•	Copy Counter to Center Freq sets the measurement center frequency to the current frequency counter reading.

Keyboard shortcuts exist for some of these functions if a trace marker is turned on. Right-click in the trace. The menu includes Copy Marker to Center Freq, Copy Marker to Ref Level, Copy Marker to Despread, and Copy Marker to Offset.


Marker Tools

Menu Path: Markers > Tools

Ordinarily the pointer is shaped like an arrow pointing northwest, and is used to select items on the interactive display and from the menus and toolbars. Marker functions require a bit more flexibility, so the Marker menu Tools selection lets you change the pointer. The following tools are available:

	Use the Pointer Tool for selecting menu items or to edit values on the analyzer display.
	Use the Area Select tool to outline a rectangular area of any trace to mark it for closer examination.  You can use the borders of the rectangle to the following things:  - Scale the X axis and/or Y axis  - Set Center Freq and Freq Span  - Set band power markers. To reset x-axis to full scale: Right click in the blank area of the marker readouts, click X Full Scale. To reset y-axis to full scale: Right in the trace display area and click Y AutoScale.
	Use the Marker tool to place a marker at the location you point to.
	Use the Band Power tool to position and adjust band power markers. After you select the band power tool, click once within the active trace to position the center of the band power marker. Immediately, the pointer changes to a bi-directional arrow ↔. Click to expand the bandwidth of the markers. • Click and drag to shift the left, right, or center frequencies, simultaneously adjusting the span. • Shift-click and drag the left or right references to adjust the width of the band.  The unclicked reference remains fixed, and the clicked reference and center move. • Click and drag the center frequency line to move the band left or right while maintaining the same band width.
	Use the Time Gate tool to isolate a portion of a time record for further viewing and analysis. To use time gating, you identify a portion of the main time-record to be used for frequency-domain displays. For more information, see About Time Gating.

The marker tools are displayed in the analyzer's tool bar above the trace display unless you turn them off.


Position Tab (Marker Properties)
Position Tab (Markers)

Menu Path: Markers > Position

The Position tab of the Markers Properties dialog box lets you enable, disable, and position the marker and offset marker for a trace.

•	Marker:. Select the check box to enable the marker; clear the check box to disable the marker. When the marker is enabled, you can set the following parameters for the marker:

−	X Position:. Specifies the x-axis component of the marker location.

−	Z Position:. Specifies the z-axis component of the marker location. This parameter is greyed when not available.

−	Trace Time: Specifies the elapsed time from the beginning of the measurement to the current scan.

−	Polar Format:.. Choose between Real and Imaginary or Magnitude and Phase. (Switching between the two formats has no effect when the Y-axis format is Log Mag.)

−	Peak Track:. Places the marker at the peak magnitude in the trace.

−	Couple Markers:. Couple the markers on all traces.

−	Consolidate when Code Order is Hadamard: Places markers on all related code channels.

•	Offset Marker:. Select the check box to turn on an offset maker; clear the check box to turn off an offset marker. When offset marker is enabled, you can set the following parameters for the offset marker:

−	X Position:. Specify the x-axis offset marker. For spans less than full span, it is possible to specify an x-axis value for the offset marker outside of the current span. In this case, the analyzer still uses the value you enter to calculate the marker readout even though the offset marker does not appear on the display.

−	Z Position:. Specify the z-axis offset marker. For spans less than full span, it is possible to specify an z-axis value for the offset marker outside of the current span. In this case, the analyzer still uses the value you enter to calculate the marker readout even though the offset marker does not appear on the display. This parameter is greyed if not available.

−	Y Position: Enter a y-axis value and unit for the offset marker.

−	Zero Offset: Click the button to move the offset marker to the marker position.

See also

About Markers

Setting and Moving Markers


Consolidate when Code Order is Hadamard

( WCDMA(3GPP) and cdma2000 demodulation only)

Menu Path: Markers > Position

The Consolidate when Code Order is Hadamard check box controls the Code Domain Power Trace Data display marker placement. When the check box is checked, markers are placed on all related code channels (Walsh Code Number). When the check box is cleared, a marker is placed only on the selected code channel (Walsh Code Number).

Tip

You can also reorder the code channels so that all related channels are placed adjacent to each other by setting the Code Order to Bit-Reversed (Trace > Digital demod > Code Order > Bit Reversed)

See also

Position Tab


Marker Coupling

Menu Path:	Markers > Position > Couple Mkrs
or Markers > Couple Mkrs

Marker coupling means that the markers for two or more traces move together.

Marker coupling is applicable only between traces that have the same x-axis coordinates. For example, marker coupling is meaningless if one trace has x-axis units of Hertz and another trace has x-axis units of seconds.

To enable marker coupling, select the Couple Mkrs check box in the Markers Properties tab. Now, when you reposition the marker in the active trace, the marker(s) for the inactive trace(s) moves to the same point as the marker in the active trace.

Note

Because marker coupling has lower priority than peak track, marker coupling does not work if both marker coupling and peak track are turned on.

Marker coupling is quite useful. For example, if you display frequency response magnitude on the upper trace and phase on the lower, you can use marker coupling to track both magnitude and phase at each X-axis position.

See also

About Markers

Position Tab


Peak Track

Menu Path: Markers > Position > Peak Track

When peak tracking is on, the analyzer automatically positions the marker on the highest point of the active trace each time the trace is updated. The definition of "highest point" is as follows:

•	The "highest point" is the point with the largest y-axis value.

•	For polar (IQ) data format, "highest point" is the point with the largest magnitude.

If peak tracking is on for more than one trace, each marker follows the peak for its respective trace.

Note

If you move the marker or use marker search when Peak Tracking is on, Peak Tracking turns off and the marker moves to the new location.

See also

About Markers

Position Tab


Polar Format (Markers)

Menu Path: Markers > Position > Polar Markers

This check box lets you toggle between "Magnitude & Phase" and "Real & Imaginary" polar formats. Switching between the two formats has no effect when the Y-axis format is Log Mag.

Note

The Marker check box must be checked to enable this feature.

See also

About Markers

Position Tab


Show Marker

Menu Path: Markers > Show Marker
Or: Markers > Position

Default:. Markers Off

Select Show Marker to turn the Marker features on or off. The marker determines the x-axis, z-axis, and y-axis position for any point on a trace.

The marker shows as a diamond on the trace: the offset marker shows as a square.

When the marker is on, the analyzer displays marker readouts just below the traces. The marker values and data results reflect the trace marker location. The marker readouts can be absolute or relative depending on the Marker Offset parameter (see Marker Offset).

Turning Markers ON

You can turn on a marker in the active trace in several ways:

•	Click Markers > Position >  Marker check box. Then you can enter a specific X-axis and Y-axis location for the marker.

•	Right click in the trace and click either Show Marker or ↑Peak (the latter turns on a marker and positions it at the highest Y-axis value).

•	Click the marker tool [image], then click in the trace where you want to place the marker.

•	Click Markers, Show Marker.

Turning Markers OFF

You can turn off the marker and offset marker by clicking Markers > Position, and clearing the Marker and Offset marker check boxes in the dialog box. You can also right-click in the trace and clear Show Marker and Show Offset.

See also

About Markers

Offset Marker

Marker Shortcuts


Show Offset Marker

Menu Path: Markers > Show Offset
Or: Markers > Position

Default:	Offset Markers Off

Select Show Offset Marker to turn the Offset Marker features on or off. The Offset marker shows you how far the marker is from a reference point (the offset marker position).

When the marker is on, the analyzer displays marker readouts just below the traces.

The marker readout can be absolute or relative. The absolute marker values reflect the absolute x-axis, z-axis, and y-axis values. By turning on the offset marker, you can find relative values between two points. The analyzer uses the position of the offset marker (indicated by a small square) as a reference point. In this case, marker values shown are relative to the offset marker.

Using Offset Markers

The offset marker is a square-shaped marker that remains at a fixed location—even when a trace is updated. To position the offset marker to any location, use the X Position, Z Position and Y Position boxes in the Markers Position tab. You can also hold down the shift key, click on the offset marker, and drag it to a new position.

If you turn on an offset marker when the trace marker is not turned on, the analyzer automatically turns on the trace marker.

You can turn on offset markers in several ways:

•	Click Markers > Position > Offset Marker check box. Then you can enter a specific X-axis or Y-axis location for the offset marker. For spectrogram displays, you specify a trace time. For other three-dimensional displays, you can specify a Z-axis position.

•	Right-click in the trace and click Show Offset.

•	Click Markers, Show Offset.

Here are three ways to position the Offset Marker to the current marker position:

•	Hold down the shift key, click on the offset marker, and drag it to the marker position.

•	Click Markers > Copy Marker to > Move Offset to Mkr. If the offset marker is not enabled, this enables the marker and sets it at the current marker position.

•	Click Markers > Position > Zero Offset. (This works only if the offset marker is already enabled.)

When the offset marker is on, the analyzer subtracts the main marker position from the offset marker position to establish the values displayed in the marker readout. The readout is preceded by the word "offset" to show that this difference is being displayed.

The offset marker position at power-up and reset is 0. At any other time, the offset marker position maintains its most recent setting.

For spans less than full span, you can specify an x-axis value for the offset marker outside of the current span. In this case, the analyzer still uses the value you enter to calculate the marker readout even though the offset marker does not appear on the display.

See also

About Markers

Position Tab


Trace Time

For offset markers with spectrogram displays, you specify Trace Time rather than Z position. The trace time is the time since the measurement start. The offset marker appears at the scan closest to the specified trace time. If the trace time is greater than the measurement elapsed time, the offset marker appears at the bottom of the display. If the trace time is less than the measurement elapsed time at the top of the display, the horizontal line and square for the offset marker are not displayed.

HINT

The easiest way to position the offset marker is by clicking Zero Offset in the Marker Position dialog box. This sets the offset marker at the marker position for the current scan.

For more information on markers with spectrograms, see About Spectrogram Markers.


X Position and Offset X Position

Menu Path: Markers > Position > X Position

X Position specifies the current x-axis marker position. You can move the marker to another location by entering a new value in the Marker X Position text box.

When Offset Marker is enabled, the Offset X Position specifies how far the x-axis marker position is from the x-axis offset marker. You can move the offset marker to a new location by enter a new value in the Offset X Position text box. See Offset Marker for more detailed information about marker and offset marker interaction.

The marker readouts reflect the x-axis, y-axis, and z-axis measurement results for the selected marker position. For trace data that does not have z-axis data results, the Z Position parameter is greyed and the marker readout is blanked.

See also

About Markers

Position Tab


Z Position and. Offset Z Position
Z Position and Offset Z Position

(OFDM Demodulation measurements only)

Menu Path: Markers > Position > Z Position

The Z Position and Offset Z Position parameters are applicable only for the OFDM Error Vector Spectrum and OFDM Error Vector Time trace data displays. These displays use 3-dimensional data; that is, the data results include x-axis, y-axis, and z-axis components. For trace data without a z-axis component, the Z Position, and Z Offset parameters are greyed.

Z Position

Z Position specifies the current z-axis marker position. You can move the marker to another location by entering a new value in the Z Position text box.

Offset Z Position

When Offset Marker is enabled, the Offset Z Position specifies how far the z-axis marker position is from the z-axis marker offset position. You can move the offset marker to a new location by enter a new value in the Offset X Position text box. See Offset Marker for more detailed information about marker and offset marker interaction.

Marker Readouts

The marker readouts reflect the x-axis, y-axis, and z-axis measurement results for the selected marker position. Selecting (clicking) the x-marker readout makes the x-axis the active display axis and selecting z-marker readout makes the z-axis the active display axis. For trace data that does not have a z-axis component, the Z Position parameter is greyed and the marker readout is blanked.

See also

About OFDM Markers

Position Tab

Marker Shortcuts


Calculation Tab (Marker Properties)
Calculation Tab (Markers)

Menu Path: Markers > Calculation

The Calculation tab of the Marker Properties dialog box lets you enable and disable the frequency counter and band power markers.

•	Frequency Counter: Select the check box to enable the frequency counter. Clear the check box to disable the frequency counter.

•	Band Power: Select the check box to enable band power markers.

−	Center/Width: When the check box is checked, you can set center and width frequencies for the band.

−	Left/Right: When the check box is cleared, you can set Left and Right frequencies for the band.

−	Calculate: From the list, you can choose the computation you want to perform on the data within the band.

Note

Band Power markers for OFDM demodulation provide capabilities unique to OFDM trace data displays, see OFDM Band Power Markers

•	Analog Demod Carrier: Select the check box to display the estimated carrier for analog demod measurements. This does not work for AM modulation, and if Auto Carrier Frequency is cleared in the Analog Demod dialog box, Analog Demod Carrier defaults to the marker value.

See also

About Markers

Band Power Markers and Scalar Measurements

OFDM Band Power Markers


Frequency Counter (Calculation tab)
Frequency Counter

Menu Path: Markers > Calculation > Frequency Counter

When Frequency Counter is on, the analyzer uses a narrower ResBW around the marker to more precisely calculate the frequency of the largest signal component at the marker.

The Frequency Counter is on when the Frequency Counter check box is checked in the Markers Properties Calculation tab and a marker is turned on in the trace.

To use the Frequency Counter, follow these steps:

1.	Set Trigger Type to Freerun.

2.	Turn Time Gating off.

3.	Start the measurement.

4.	Choose a frequency domain Trace Data (Spectrum, PSD, or Inst Spec).

5.	Turn on the trace marker and position it at a peak.

6.	Click Markers > Calculation.

7.	Click the Frequency Counter check box. When a count has been completed, the marker readout includes a line labeled "Freq."

8.	Right click in the trace grid and click Copy Counter to Center Freq.

Now you can vary the frequency span to more closely examine the peak signal.

Note

Frequency Counter does not work with recalled traces, recorded data, or data from the ADS interface. Frequency Counter works with simulated hardware, but the results are not quite as accurate as with live data from measurement hardware.

The Frequency Counter readout is valid only for the configurations in the following table:

Parameter:	Setting:
Marker	On
Trigger Type	Free run
Time gating	Off
Measurement Data	Spectrum, PSD, or instantaneous spectrum
Frequency Counter invalidity

If Frequency Counter is on and the conditions listed in the previous table are not met, the readout indicates that the frequency is not valid. Here are some examples of an invalid Frequency Counter:

•	When Frequency Counter is on, the analyzer estimates the length of the data block required to calculate the frequency. If the signal-to-noise ratio is very low, or the frequency span is very narrow, the analyzer will be unable to accurately estimate the frequency. In this case, the Frequency Counter readout displays "Not a valid measurement."

•	The Frequency Counter counts only data from the current input spectrum. If you select trace data that is not linked to the input spectrum—for example, Auto Correlation—the readout displays "Not valid for this trace data."

If you display recalled traces, recorded data, data register contents, or data from the ADS interface, the readout displays "Not a valid measurement."

See also

Marker Calculations


Band Power Markers. (Calculation tab)
Band Power Markers Overview

Menu Path: Markers > Calculation > Band Power

Band-power markers provide a quick way to make several different power computations. This topic includes the following information:

•	Band Power Marker display

•	Turning on band power markers

•	Positioning the band power markers

•	Band-power marker calculations

Band Power Marker display

This display shows band-power markers turned on for a spectrum measurement in Trace A (the trace grids are turned off so it is easier to see the markers):

The band-power markers consist of two solid vertical lines spaced equally on either side of one dotted vertical line. The left vertical line is called band left; the right vertical line is called band right. The center dotted vertical line indicates the center of the band.

The results of the band computation are displayed in the marker area below the traces.

Note

If the trace is the result of a math function performed on Spectrum Analyzer data (any data that consists of min/max pairs), you cannot use band power markers for the trace.

Turning on band power markers

There are several ways to turn on band power markers:

•	Right-click in the trace and select Show Band Power from the menu.

•	Click the band power tool [image] in the tool bar. Then click in the trace where you want the band center to be.

•	Click Markers > Calculation and select the Band Power check box.

•	Click the select area tool [image] and then move the mouse to the measurement grid. While left-clicking the mouse, drag over the frequency band of interest. From the menu, select Band Power and click OK. The band power markers will be placed over this selected area.

Positioning the band power markers

If you have turned band power markers on, but the markers do not appear in the trace, click the trace where you want the band center.

You can change the position of the band power markers in two ways:

1.	Using the mouse

2.	Using the Markers menu

Using the mouse

•	To move the center frequency, place the pointer on the band center and drag the center line. The bandwidth remains constant, but the band center changes.

•	To maintain the band center but change the width

−	If the Center/Width check box is checked, place the pointer on band left or band right and drag to the desired width. The center remains fixed.

−	If the Center/Width check box is cleared, hold down the shift key, place the pointer on band left or band right and drag to the desired width. The center remains fixed.

•	To maintain band left but change band center and band right:

−	If the Center/Width check box is checked, place the pointer on band right, hold down the Shift key, and drag to the desired width.

−	If the Center/Width check box is cleared, place the pointer on band right and drag to the desired width.

•	To maintain band right but change band center and band left:

−	If the Center/Width check box is checked, place the pointer on band left, hold down the Shift key, and drag to the desired width.

−	If the Center/Width check box is cleared, place the pointer on band left and drag to the desired width.

Using the Markers menu

•	Click Markers > Calculation. If the Center/Width check box is checked, the position of the band power-markers is determined by these two settings:

−	Center determines the center position of the band-power markers.

−	Width determines the width of the band-power markers.

•	If the Center/Width check box is cleared, the position of the band power-markers is determined by these two settings:

−	Left determines the location of the left band-power marker.

−	Right determines the location of the right band-power marker.

Band-power marker calculations

You can make the following power calculations using the band-power markers:

•	Band Power displays the total power between the band-power markers.

•	RMS Sqrt (Pwr) displays the square root of total power between the band-power markers.

•	C/N computes and displays carrier-to-noise.

•	C/No computes and displays carrier-to-noise density.

Note that for OFDM displays the band power calculations are the rms average of all values in the band.

See also

Marker Calculations


Band Power Calculation

Menu Path: Markers > Calculation > Calculate list > Band Power

When band power markers are enabled and you select Band Power from the Calculate drop-down list, the analyzer computes and displays the power within the region marked by the band-power markers for the active trace. The value is displayed in the marker area below the trace and above the status line.

Band Power and Frequency-Domain Data

For frequency-domain data, band power is the total power within the band. In other words, the analyzer sums the powers of the points within the band and displays the result in the current Y-axis units.

Band Power and Time-Domain Data

For time-domain data, band power is the power within the band, normalized to one point. In other words, the analyzer sums the powers of the points within the band, and then divides by the number of points within the band. The analyzer displays the result in the current Y-axis units.

Note

For best accuracy with sinusoidal, baseband waveforms, the width of the band power markers (band width) should be an integral number of cycles. For baseband analysis (the data is real, not complex), accuracy is degraded if an integral number of cycles is not used.

Band Power and Spectrum Analyzer Measurements

Band Power calculations with the Spectrum Analyzer application (scalar measurements) behave differently. For details, see Band Power Markers and the Spectrum Analyzer Application.

Band Power and Code Domain Data

For Code-domain trace data, band power is the sum of the power within the band. The analyzer displays the result in the current Y-axis units.

Band Power and OFDM Data

For some OFDM data, band power is the RMS average value within the band. The analyzer displays the result in the current Y-axis units. The applicable OFDM trace data include OFDM Error Vector Spectrum, OFDM Error Vector Time, OFDM IQ Meas, and OFDM IQ Ref trace data.

Tip

To match the trace data marker readout computation type, select RMS Sqrt(Pwr) from the Calculate drop-down list.

Band Power and Units

Band power units can be dB, dBm, dB/Hz, Vrms, Vrms^2, watts, %rms, or %rms^2 depending on the current data format. The units may be preceded by "m" (milli), "u" (micro), or "n" (nano).

See also

Band Power Markers Overview.

Band Power Markers and Spectrum Analyzer Measurements

Marker Calculations


RMS Sqrt (Pwr) (with band-power markers)

Menu Path: Markers > Calculation > Calculate list > RMS

Select RMS Sqrt (Pwr) to compute and display the square root of band power for the active trace.

The value is displayed in the lower left corner of the trace box, in units of Vrms.

To learn how the analyzer calculates band power, see Band power.

For an overview of band-power markers, see Band power markers.

See also

Band Power Markers (overview).

Band Power Markers and Spectrum Analyzer Measurements

Marker Calculations


Power Ratios (C/N and C/No with band-power markers)
Power Ratios (C/N and C/No)

Menu Path: Markers > Calculation > Calculate list > C/N or C/No

The analyzer calculates C/N and C/No as follows:

To display C/N or C/No, do this:

1.	Turn on the marker and position it at the peak of your carrier signal. The easiest way to do this is to right-click in the trace and click. ↑ Peak from the menu

2.	Turn on the band-power markers and position them to include the noise you want in the carrier-to-noise calculation, but not the carrier. The calculation is incorrect if the band-power markers include the carrier.

3.	Click Markers > Calculation > the arrow to the right of Calculate. Select C/N from the list to compute and display carrier-to-noise, or select C/No to compute and display carrier-to-noise-density.

The computed value is displayed below the marker in the marker readout below the traces. The analyzer prefixes the displayed value with C/N: or C/No:. If the marker is off, the analyzer prefixes the displayed value with N: or No:, where N: is the band power and No: is the band- power-density, which is (band power)/(band width).

The units displayed for C/N or C/No depend on the y-axis units. If the y-axis units are dB, C/N is displayed in dB; C/No is displayed in dB/Hz. For any other y-axis units, C/N is displayed unitless; C/No is displayed as a unitless number per Hertz. Unitless numbers may be followed by "m" for milli, "u" for micro, or "n" for nano. For example, the analyzer displays 0.001 as 1 m.

If a marker is not turned on the trace, C/N and C/No revert to band power.

See also

Band Power Markers (overview).

Band Power Markers and Spectrum Analyzer Measurements

Marker Calculations


Band Power Markers and Scalar Measurements
Band Power Markers and the Spectrum Analyzer Application

Band power is calculated differently by the Spectrum Analyzer application (scalar measurements).

How Scalar Measurements Derive Band Power

The trace for a scalar measurement is a data vector that represents detected information from the segments that make up a scalar sweep. Each bin in the data vector has a frequency width of:

(StopFreq − StartFreq) / Number Of Frequency Points

Before detection, each bin contains several values that represent the magnitude of each frequency point within the bin. After detection, each bin contains two values that represent the minimum and maximum magnitude of the frequencies within the bin. Because detection discards all but the min/max values in each bin, it is impossible to later extract the exact power for a band of frequencies.

To solve this problem, the detection process also produces a hidden data vector. Each bin in the hidden data vector contains a value that represents the bin's integrated power. Scalar measurements use the hidden vector to derive band power. As long as the band-power markers begin at the start of a bin and end at the end of a bin, the band-power results are accurate.

The Problem

If the left or right band-power marker falls between display bins, the analyzer sums the partial power for that bin. In doing so, the measurement assumes that the power in the bin is evenly distributed across the bin. This assumption works well if the power in the bin is due to noise, but can cause a problem if a signal exists somewhere within the bin.

This problem affects the Band Power calculation when the resolution bandwidth (ResBW) is smaller than the width of a bin and when the left or right band-power marker falls within a bin that has a signal present. The Band Power calculation assumes that the signal power is evenly distributed across the entire bin and will sum extra power, or not enough power, into the result.

The Solution

There are two ways to solve this problem:

•	Place the Band Power markers so that all bins that contain signals are entirely within the band-power markers.

•	Change the frequency span, ResBW, or the number of frequency points to ensure that the width of each bin is equal to or less than the ResBW.

Note

If the trace is the result of a math function performed on Spectrum Analyzer data (any data that consists of min/max pairs), you cannot use band power markers for the trace.

See also

Band Power Markers Overview.


About Spectrogram Markers

 Menu Path: Markers > Spectrogram

Markers behave differently for spectrogram displays than for other displays. The analyzer uses a vertical line to indicate the current marker position (if the marker is on), and a vertical line with a box to indicate the current offset-marker position. The offset marker display also includes a horizontal line at the offset marker time. In the following illustration, the markers are the purple lines in the middle of the display.

By default, the analyzer places the marker on the most recent (bottom) scan. To position the marker on other traces in the spectrogram, turn on trace select and select the desired trace. In the following illustration, the white horizontal line indicates the selected trace (scan).

Marker-search operations are confined to the selected scan.

You can specify colors for spectrogram markers and trace select markers by clicking Display, Appearance, Color. Then select the appropriate marker from the Element List, click Color…, and choose a color.

Marker Readouts for Spectrogram Markers

The marker readout for spectrogram displays varies, depending on which markers you have turned on and what kind of trace data is displayed:

Marker settings	Readout values, left to right
Marker: on Offset: off Trace select: off	1. Time elapsed since the start of the measurement 2. X-axis value 3. Y-axis value
Marker: on Offset: on Trace select: off	1. Time difference between the offset marker scan time and the most recent (bottom) scan time 2. X-axis offset 3. Y-axis offset
Marker: on Offset: on Trace select: on	for time domain trace data: 1.   Aggregate time—the sum of these two quantities: • Time difference between the offset marker and marker, the x-axis offset • Time difference between the offset marker scan time and the marker current trace scan time 2.   Y-axis offset
Marker: on Offset: on Trace select: on	for all other trace data: 1. Time difference between the offset marker scan time and the marker scan time 2. X-axis offset 3. Y-axis offset
Marker: off Offset: off Trace select: on	Nothing displayed in marker readout. Elapsed time since the start of the measurement is displayed in Spectrogram Marker dialog box.
See also

Markers

Offset Markers

Trace Select

Color tab


Trace Select (Spectrogram Marker)

Menu Path: Markers > Spectrogram

Trace Select turns on trace selection for spectrogram displays. This feature lets you select any trace in a spectrogram display. By default, the marker is on the most recent trace (the bottom trace in a spectrogram display).

Note

This feature is available only when the active trace is a spectrogram display, and the measurement is paused. When the measurement is running, the marker is always on the most recent trace.

When Trace Select is checked, the Trace box indicates which trace is selected. For example, if the Trace box shows a value of 10 scans, the marker is currently on the 10th trace in the spectrogram buffer.

Spectrogram displays use a horizontal line to show the selected trace (and a vertical line to show the current marker position on the trace).

You enter a value in the Trace box to select a trace. You can select a trace either by scan number or by time relative to when the measurement was started.

If you specify a span, the value you enter in the Trace box is limited to the number of traces specified by Buffer Depth. For example, if Buffer Depth is set to 200, valid values for Trace are from 1 to 200 scans. The spectrogram display may show more traces than are in the buffer, but you can apply markers only to traces included in the buffer.

Automatic Updating of Other Traces

Another feature of trace select is that it automatically updates all displayed traces that have the same measurement data as the first spectrogram display.

In the above screen example, trace A contains a spectrogram of channel 1 spectrum. Trace B displays channel 1 spectrum. The trace select marker for trace A is set to 184. The spectrum displayed in trace B is trace number 184 from the spectrogram in trace A.

The easiest way to understand this feature is to try it. For example, display two grids with a spectrogram display in trace A and a non-spectrogram display in trace B. Select the same measurement data for both traces. Turn on trace select, click in the Trace box, and use the up and down arrow keys to change the trace number. Watch trace B update as you scroll through traces in the trace A spectrogram.


About Math Functions

Menu Path: Utilities > Math

Math functions let you create mathematical expressions that operate on trace data. You can use math functions to:

•	Perform mathematical operations on trace data.

•	Create a mathematical expression that you can apply as a filter to a waveform.

•	Manipulate data in the data registers.

Math functions can be simple or complex. For example, a simple math function may add two data registers. Another math function may compute the inverse FFT of trace data such as channel 1 spectrum-data. Or a more complex math function may combine operations on trace data or data registers.

Note

All math operations are performed on linear data, even if the trace format is logarithmic magnitude. For log traces, math operations are performed before the trace data is converted from linear to log values.

Trace titles of math functions have a prefix of "Fn", followed by the name of the math function. For example, "Fn ChanImplResp" is the trace title of a math function named ChanImpResp.

Trace Blanking and Math

Math attempts to track trace blanking from the operand to the result. Trace blanking occurs as a result of the Group Delay Aperture or if the start frequency or stop frequency is set outside the valid values.

See also

Manipulating Math Functions

Creating Math Functions

Math Function Editor Dialog Box


Manipulating Math Functions

Menu Path: Utilities > Math

You view, modify, or delete math functions from the Math Functions dialog box (click Utilities > Math). The Math Functions dialog box shows all currently available math functions and includes buttons that let you view, edit, delete, or create a math function.

To view or  edit a  math function	1. From the main menu, click Utilities > Math. 2. Select the math function. 3. Click the Edit button
To delete a  math function	1. From the main menu, click Utilities > Math. 2. Select the math function. 3. Click the Delete button
To create a  math function	1. From the main menu, click Utilities > Math. 2. Click the New button.
To display a  math function	See Selecting Trace Data
See also

About Math Functions

Creating Math Functions

Math Function Editor Dialog Box


Math Function Editor Dialog Box

Menu Path: Utilities > Math > New button

You use the Math Function Editor dialog box to edit a math function or to create a new math function.

Name   box	Lets you modify the name of the math function. The name can be up to 256 characters in length.
Expression   box	Shows the current expression for the selected math function. You can use the Function, Trace, and Operator buttons to build a math function or type it directly in the Expression box.
Function   Button	Displays the Select Function dialog box, which lets you select mathematical functions, such as FFT, log, or square root. Clicking a function displays a brief description about the function.
Trace Data   Button	Displays the Select Trace Data dialog box, which lets you choose the operand for your math function. In this case, the operand is any valid trace data or the contents of a data register. Data registers are only listed if they exist. For details about any of the listed trace data, see Available Trace Data. For details about data registers, see Saving and Recalling Data Registers.
Operator   Buttons	The operator buttons (+, -, *, /) let you perform simple mathematical operations such as addition, subtraction, multiplication, and division. Click the Function button if you want to use complex mathematical functions such as log or square root.
Check Syntax   Button	If you build a math function using the Function, Trace, and Operator buttons, the syntax of your math function should be correct. However, if you manually modify the contents of the Expression box, you may create an invalid math function. Clicking the Check Syntax button checks the syntax of your math function and reports an error if the syntax is invalid.
Apply   Button	Creates and applies the math function. Any trace that uses the math function is updated when you click the Apply button. If you click OK without clicking the Apply button, the math function is not applied until you close all math function dialog boxes.
See also

About Math Functions

Manipulating Math Functions

Creating Math Functions


Creating Math Functions

Menu Path: Utilities > Math > New button

1.	Click Utilities > Math > New button to display the Math Function Editor dialog box.

2.	In the Name box, enter the name of your math function.

3.	Use the Function > Trace Data > arithmetic operator buttons (+, -, *, /) to construct your math expression. You can also type in a constant value (see below), either scalar or vector. You can also use data registers (see below).

4.	Click the Check Syntax button to locate and fix any syntax errors.

5.	Click the Apply button to update any traces that use the math function. If you click OK without clicking the Apply button, traces are not updated until all you close all math-function dialog boxes.

IMPORTANT

Math functions may produce large errors if the real or imaginary parts of the input signal exceed pi/2 (pi/2 in Vpk is about 14.0 dBm).

Closing the Math Function Editor dialog box automatically creates a file that contains your math function. The file is saved in the under the name you assigned the function with MTH as the extension.

Entering constants in math functions

You are not limited to buttons and selections from lists. You can also type in constant values (either scalars or vectors) to be used in calculations.

For example, to double the amplitude of a spectrum, you could create the following math function (the commas separate buttons or key presses—do not type the commas) to double the amplitude. (Note that if you are displaying LogMag, the amplitude increases by 6 dB.)

Click Trace Data > Spectrum 1 > OK > *, type 2, and click OK.

Or you can shift the phase of a time-domain signal 90 degrees by multiplying the signal by (j1) (the commas separate buttons or key presses—do not type the commas):

Click Trace Data > Inst Main Time 1 > OK, *, type (j1), and click OK.

Using math on data registers

Data registers are listed in the list of Trace Data only if the register contains information. Empty data registers are not listed. If you want to perform math operations on data registers, you must first copy or recall data into the registers.

See also

About Math Functions

Manipulating Math Functions

Math Function Editor Dialog Box

Math Trace Data

To Select Trace Data


Importing and Exporting Math Functions

Math functions are stored under the name you assign the function, and they are available only for the application you use to create them. This means that math functions created in the Vector Signal Analyzer are not available in the Scalar Analyzer application

If you want to use a math function in both applications, you must copy it from the Math Function Editor dialog box in one application and paste it into the Math Function Editor dialog box in the other application.


About Default Menus

When you perform a Preset Menu/Toolbars or Preset All, the contents of the menus are returned to their defaults. The topics in this book describe the defaults for each of the menus available from the menu bar. The menus are:

•	Control

•	Display

•	Edit

•	File

•	Help

•	Input

•	Markers

•	MeasSetup

•	Trace

•	Utilities

•	Popup menus


Control Menu

The Control menu allows you to start and stop measurements in several ways. Some of the menu entries are duplicated in the Control Toolbar.

This menu item…	Lets you do this…
Restart	Start a new measurement.
Pause/Single.	Pause or single step a measurement.
Stop	Stops the current measurement.
Disconnect	Stops all communication between the analyzer software and hardware.
Record	Turn on recording.
Player	Opens the waveform playback feature
Sweep	Switch between Single and Continuous sweeps.


Display Menu

The Display menu lets you customize the display, as described below:

This menu item…	Lets you do this…
Menu/Toolbars	Customize what appears in the display menu and toolbars.
Appearance	Change the appearance of the display, including colors, fonts, and number and placement of trace displays.
Layout	Specify the layout of the traces
Active Trace	Specify the active trace.
View/Overlay Traces	Select the trace or traces you want to display.


Edit Menu

The Edit menu provides three functions:

This menu item…	Lets you do this…
Undo	Reverse the last action performed on a trace.
Copy Trace Data	Write the current trace data to the clipboard.
Copy Text	Write the content of the current text box to the clipboard.
Copy Markers	Write the current marker data to the clipboard.


 File Menu

The File menu lets you preset many parameters to their factory defaults, save and recall files, copy traces into data registers, remove data registers, send results to a printer, or exit the application, as described below.

This menu item…	Lets you do this…
Recall	Recall the following information: − Instrument setups − Menus and toolbars  − The display appearance (colors and fonts) − The User Color Map for spectrogram displays − State Definitions  − Individual traces and recordings
Preset	Reset the instrument to factory default conditions. You can independently preset the measurement setup, the menus and toolbars, the display appearance, user color map, and the state definitions, or you can elect to preset all settings to the factory defaults.
Save	Save the following information: − Instrument setups − Menus and toolbars. − The display appearance (colors and fonts) − The User Color Map for spectrogram displays. − Individual traces and recordings
Copy Trace	Copy the currently active trace to one of the data registers D1 through D8.
Remove Register	Clear a data register.
Print	Print the active trace. For help on this topic, click Print to open the Print dialog  box. Then click the question mark in the upper right corner.    The cursor changes shape. Click on areas of the dialog box to get help.
Print Setup	Specify and configure a printer in preparation for printing. Access help as explained for Print.
Exit	Closes the analyzer application.
See Also

About Save and Recall

About Preset

Saving and Recalling Data Registers


Help Menu

The Help menu provides access to the help files.

This menu item…	Does this…
Roadmap	Displays a master list of help files.
Getting Started	Displays an overview of the analyzer and how to use it.
Tutorial	Guides you through several example measurements.
Contents	Displays the table of contents for reference help
How to use Help	Displays information on the MS Windows help system.
About Agilent VSA	Displays information about the analyzer, including what software version is installed on your computer.
Note that there are many inter-linked help files. If you traverse a link from one help file to another, the Table of Contents displayed in the left-hand pane still reflects the help file where you entered. To completely leave one help file and start over, use the Roadmap button that is located at the top of all the help files.


Input Menu

The Input menu lets you select and configure one or more input channels and select the data source, as described below:

This menu item…	Lets you do this…
Channels	Select one or two input channels (if the second input channel is installed). If your analyzer has two input channels, you can also select I+jQ (Ch1+j*Ch2), which configures the analyzer to accept real data (I) on Channel 1, and imaginary data (Q) on Channel 2.
Range	Set the input range for each input channel (each ADC module in your VXI mainframe).
Coupling	Select AC or DC coupling for each input channel (each ADC module in your VXI mainframe).
Trigger	Select the type of trigger signal you want to use for an input channel. If you have two input channels , see Triggering Multiple Channels to learn how to trigger from either input channel.
Playback Trigger	Set up a trigger signal for recordings. Unavailable for the Spectrum Analyzer application.
Data From	Select the source of your data: either from an input channel or from a recording. Unavailable for the Spectrum Analyzer application. To learn how to analyze data from: • Input channels, see Input Channels. • Recordings, see Recordings. • Software development tools, see Sharing Data with Other Products and Applications.
Recording	Set recording parameters.  Unavailable for the Spectrum Analyzer application.


Markers Menu

The Markers menu lets you perform the following marker functions:

This menu item…	Lets you do this…
Position	Turn on and position a marker and an offset marker, turn on and off peak tracking and marker coupling.
Calculation	Set up band power markers, specify what a value to be calculated, and turn the frequency counter on or off.
Spectrogram	Set up spectrogram markers.
Search	Move the marker to a specific x-axis location.
Copy Marker to	Quickly set the value for many parameters to the current marker value.
Tools	Choose from marker tools (duplicate of the marker tools toolbar).
Show Marker	Turn the marker on or off.
Couple Mkrs	Couple the markers in the displayed traces.
Show Offset	Turn the offset marker on or off.


MeasSetup Menu

The MeasSetup menu provides all the selections for setting up a measurement

This menu item…	Lets you do this…
Frequency Bands	Choose the appropriate frequency band.
Frequency	Set up center and span or start and stop frequencies.
ResBW	Set up resolution bandwidth and window parameters.
Time	Set up time and time gating parameters.
Average	Set up averaging parameters.
Demodulator	Control and set the analyzer demodulation type.
Demod Properties	Set up the demodulation configuration and associated parameters.


Source Menu

The source menu provides integrated control for an external source and the means for defining, cataloging and generating arbitrary waveforms.

This menu item…	Lets you do this…
Output	Select a waveform and control the signal generators RF Output.
Control	Control and Configure the signal generator.
Arb Waveforms	Define, Save, Recall user defined arbitrary waveforms.
See also

About Source


Trace Menu

The Trace menu permits the selection of a for the active trace.

This menu item…	Lets you do this…
Data	Select which measurement results to display.
Format	Specify Y-axis coordinates for the trace.
Y scale	Set up Y-axis scale parameters, including units, reference level, reference position, and units per division.
X scale	Set up X-axis scale parameters, including left and right reference values.
Digital Demod	Set up digital demodulation trace parameters, including symbol table format, symbol shape, ideal state shape and size, eye length, and time unit..
Spectrogram	Set up spectrogram display parameters, including buffer depth, color count, map color, enhancement, and threshold value.
Y Auto Scale	Automatically scales the Y axis to best display the measured data.


Utilities Menu

The Utilities menu provides includes the following features:

This menu item…	Lets you do this…
Math	Create and edit custom mathematical functions.
Macros	Create custom VBScript macros.
Hardware	Select among the available hardware for the Input Channels, RF Converter, and ADC. A second check box causes the instrument to simulate hardware in those cases when hardware is unavailable.
Reference Frequency	Set up the frequency for internal or external reference.
License	Modify your license or move it to another computer.
Calibration	Set up parameters for calibrating the analyzer.
Single Cal	Perform an immediate, single calibration of the analyzer.
Extended Cal	Set up and perform an extended calibration of your measurement hardware.


Popup Menus

In many areas on the display, right clicking the mouse brings up a popup menu that contains frequently used menu items for that area of the display. The following popup menus are available:

•	Calibrate Popup Menu

•	Data Entry Popup Menu

•	Edit Popup Menu

•	External Reference Popup Menu

•	Toolbar Popup Menu

•	Trace Title Popup Menu

•	Trace Popup Menu

•	X-Axis Popup Menu

•	Y-Axis Popup Menu


Calibrate Popup Menu

Right-clicking in the Calibration Status area displays the Calibrate popup menu.

	Calibration… brings up the Calibration dialog box. Single Cal initiates a measurement hardware self-calibration. Extended Cal starts the Extended Calibration Wizard.


Data Entry Popup Menu

Right-clicking a text entry box displays the Date Entry popup menu. The selections from this menu behave like standard MS Windows operations. The only exception is that when you copy numerical values, they are unscaled. For example, if you copy "1 MHz," the clipboard contents are "1000000 Hz" rather than "1 MHz."

	Undo reverses the last change you made. Cut removes the text from the text entry box and puts it on the clipboard. Copy leaves the text in the text entry box and puts it on the clipboard. Paste deletes the highlighted text from the text entry box and replaces it with the clipboard contents. Delete removes the highlighted text from the text entry box. Select All highlights everything in the text entry box.


Edit Popup Menu

Right-clicking a parameter hotspot displays the Edit popup menu.

	Edit lets you change the parameter (this is the same as double-clicking the hotspot parameter). Copy Text puts the unscaled text on the clipboard. For example, if you copy a Center Frequency of 1 MHz, the text "1000000 Hz" goes to the clipboard. Paste puts the contents of the clipboard into a data entry text box for the parameter. This is a "smart" paste operation. It tries the following steps in order: 1. Search the text on the clipboard for units that are sensible in the current context, and use them and the associated value. 2. Search for any unitless number on the clipboard and use the first one it finds with the base units currently associated with the paste target. 3. Search for a number followed by any units and offer to use the number with the current base units associated with the paste target. You always get a chance to confirm the paste operation. Default changes the parameter to its default value.


External Reference Popup Menu

Right-clicking in the System Reference Lock State area brings up the External Reference popup menu.

	Reference Details opens the Reference Details dialog box. Reference Frequency opens the Reference Frequency dialog box.


Toolbar Popup Menu

Right-clicking in the menu bar or toolbar displays the Toolbar popup menu. The Menu/Toolbars entry opens the Menu/Toolbars dialog box. All other entries enable or disable display of specific toolbars. If there is a check next to an entry, that toolbar will be displayed. If there is no check, the toolbar will not be displayed.

	Control turns the control toolbar on or off. Active Trace turns the active trace toolbar on or off. Macros turns the macros toolbar on or off. Marker Tools turns the marker tools toolbar on or off. Marker Search turns the marker search toolbar on or off. Popup Menus turns the popup menu toolbar on or off. Spectrogram turns the spectrogram toolbar on or off. Menu/Toolbars opens the Menu/Toolbars dialog box.


Trace Popup Menu

Right-clicking within a trace displays the Trace popup menu, which contains a selection of frequently used trace operations.

	Y Auto Scale autoscales the trace (same as clicking Trace, Y Auto Scale from the main menu). Show Marker and Show Offset enable or disable the marker and offset marker. Show Band Power enables or disables band-power markers for the active trace. Enable Time Gating enables or disables time-gating (time-gating is only applied to a trace that has time-domain data). Show Spectrogram turns the spectrogram display on or off for the trace. Peak moves the marker to the peak value. The remaining operations are a selection from Markers, Copy Marker to on the main menu. These operations let you use the marker's current value to set frequently-used parameters.


Trace Title Popup Menu

Right-clicking anywhere in the trace title area that is not a hot spot displays the Trace Title popup menu.

	Y Auto Scale autoscales the trace (same as clicking Trace, Y Auto Scale from the main menu). Data displays a sub-menu that lets you pick from the available trace data (same as clicking Trace, Data from the main menu). Average… displays the Average tab. Range… displays the Range/Coupling tab.


X-Axis Popup Menu

Right-clicking below the X-axis displays the X-axis popup menu, which lets you change the following frequently used parameters.

	X Full Scale sets x-axis scaling so the entire X-axis is shown. X Scale…displays the X Scale tab, which lets you change X-axis scaling and other X-axis parameters. Show Center/Span is a check box. When the check box is cleared, all traces show the current Center Frequency and Frequency Span. When the check box is cleared, traces show Start and Stop frequencies. Frequency…displays the Frequency tab, which lets you set frequency parameters. ResBW…displays the ResBW tab, which lets you set resolution bandwidth parameters. Time…displays the Time tab, which lets you set parameters for time-domain and time-gating analysis. Trigger…displays the Trigger tab, which lets you set trigger parameters. Get Freq/Inp From Spec Analyzer is only available in the Vector Signal Analyzer application. If that application and the Spectrum Analyzer application are running, clicking Get Freq/Inp From Spec Analyzer sets the following Vector Signal Analyzer parameters to match those of the Spectrum Analyzer. • Center frequency  • RBW  • Window  • Input Range  • Input Coupling  • All trigger parameters • Input connection style and impedance • Reference impedance


Y-Axis Popup Menu

Right-clicking near the Y-axis displays the Y-axis popup menu, which lets you modify frequently used Y-axis parameters.

	Y Auto Scale autoscales the trace (same as clicking Trace, Y Auto Scale from the main menu). Y Scale…displays the Y Scale tab (same as clicking Trace, Y Scale from the main menu), which lets you choose Y-axis units, set the reference level or reference position, and set other Y-axis parameters. Format…displays the Format tab (same as clicking Trace, Format from the main menu), which lets you select trace coordinates.


About Range/Coupling

Menu Path: Input > Range
Or: Input > Coupling

The Range, Coupling type (AC or DC), Connection type, and Reference Impedance are set on the Range/Coupling tab of the Input Properties dialog box.


Connection (Input)

Menu Path: Input > Range
Or: Input > Coupling

The Connection setting determines how the analyzer terminates the input channel’s connector. Depending on the current hardware selected, you can specify the input impedance and whether the input is balanced or unbalanced.

Unbalanced: This refers to an unbalanced input termination (sometimes called a Single Ended Input).
Balanced: This refers to a balanced input termination (sometimes called a Differential Input).

See also

Reference Impedance


Coupling (Input)

Menu Path: Input > Coupling

The Coupling box allows you to specify AC or DC coupling for an input channel. The default is AC coupling.

If AC or DC coupling is not an option for your hardware, it will not be available in the list.

If your analyzer is configured with two input channels, this setting affects ONLY the channel displayed in the box above Range/Coupling tab.

Notes

•	With AC coupling, the response to the input signal rolls off at low frequencies and is down 3 dB at about 8kHz. So, for low frequencies, you should use DC coupling to avoid measurement error if DC coupling is supported by your hardware.

•	DC coupling is automatically selected when you select the I+jQ(Ch1+j*Ch2) input channel.


Range (Input)

Menu Path: Input > Range

You can specify the range in either volts or dBm.

To determine what ranges are available, click the Range hotspot on the display and use the keyboard up and down arrow keys or the mouse wheel to scroll through the available ranges.

You can change the range from the Input Properties dialog box (click Input, Range), or you can click the range listed above the trace. In either case, when the field is highlighted there are two ways to change the range setting:

•	Use the mouse wheel or the arrow keys (↑ or ↓) on the keyboard to scroll through the valid ranges.

•	Type the desired range setting, select the units (optional), and click OK or press Enter. The analyzer sets the range to the closest valid value.

Note

To determine what ranges are available, click the Range hotspot on the display and use the keyboard up and down arrow keys or the mouse wheel to scroll through the available ranges.

For information on how to choose the optimum range, see Selecting the Optimum Range Value.

For information on range with non-VXI measurement hardware, see Set up Other Measurement Hardware for a link to your specific hardware.


Reference Impedance

Menu Path: Input > Range
Or: Input > Coupling

If the Same as Connection check box is selected, the analyzer automatically sets the Reference Impedance to the value of the Connection impedance. If the check box is cleared, you can specify a reference impedance.

For multi-channel analyzers, you can specify a different reference impedance for each channel. If you set Input Channels to I+jQ, however, the measurements uses the reference impedance set for channel 1, even if the channel 2 reference impedance is a different value.

The analyzer uses the reference impedance value to calculate dBm units, as follows:

In scenario #3 below, for example, if your device has an impedance of 50 Ω and the analyzer has a high impedance input, set the analyzer's input impedance to 1 MΩ, and set Reference Impedance to 50 Ω. With this configuration, dBm units are calculated as follows:

Some reference impedance scenarios:

1. If the device under test has an output impedance that matches the analyzer input impedance, you can set the Connection appropriately and select Same as Connection. Because the two impedances match, no external amplitude calibration is required.
2. If the output impedance of the device under test and the input impedance of the analyzer do not match, you can use an impedance-matching device. The impedance-matching device must have an input impedance equal to the output impedance of the device under test, and an output impedance equal to the analyzer's input impedance. In this case, you set the following parameters: − Set the Reference Impedance to the value of the device under test output impedance (75Ω in this example). − The impedance-matching device introduces some amount of insertion loss, so you must also set the External Amplitude Gain to compensate. − Be sure that Apply Corrections to Data is turned on.
3. If you are using a probe to look at the signal at a circuit node, you would set the following parameters: − Use a high input impedance Connection. − Set Reference Impedance to the load impedance of the circuit (50Ω in this example).

The analyzer corrects the amplitude based on the correct Reference Impedance and External Calibration Gain Constant settings, but the Input Range is set relative to the analyzer's input and not the impedance converter input.


Same as Connection

Menu Path: Input > Range
Or: Input > Coupling

When the Same as Connection check box is selected, the analyzer automatically sets the Reference Impedance to the value of the Connection impedance.

 When the check box is cleared, you can set the value of Reference Impedance manually. This can be useful when you are using an impedance matching device or probing a loaded circuit.


Selecting the Optimum Range Value

Menu Path: Input > Range

Setting the Range

If you set the input range too low (more sensitive than necessary), the analyzer's ADC circuitry introduces distortion into the measurement. But if you set the input range too high (less sensitive than necessary), there may be a loss of dynamic range due to additional noise--in some cases, the increase in the noise floor may even obscure low-level frequency components.

If OV1 or OV2 appears in the Trace Indicator, the ADC circuitry is being overdriven. In this case, change to a less sensitive range or reduce the input signal level.

The input circuitry is sensitive to all signals within the analyzer's frequency range--including those that are outside the current span.

Signals that are outside the current span MAY overload the ADC circuitry--causing measurement error.

Always set the range as the first step in setting up a measurement. Setting the range properly affects the input signal processing and must fulfill two conditions. First, you have to avoid overloading the input because overdriving the ADC module causes the signal to be digitized inaccurately. The second condition is to select a range that provides the best dynamic range over the entire frequency range of the instrument.

Remember that Scaling doesn't affect either of these conditions, because Scaling just acts on the display.

To optimize 3rd order distortion, the 89600 applications operate the VXI ADC modules 10 dB down from the level at which the overload indicator OV appears on the display. In other words, you only see the overload indicator when you are already overdriving the input by 10 dB.

Of course, if you are certain of the incoming signal, you can simply select the appropriate range without regard to these considerations. However, when the amplitude of the signal is in question, follow this procedure to be sure you meet the two conditions mentioned above:

1.	Start the 89600 Spectrum Analyzer application, and view the signal.

2.	Turn on a marker and search for the peak. The easiest way to do this is to click in the trace and click ↑ Peak from the menu. Select an input range greater than the Y-axis marker value (shown below the traces in the display).

3.	Start the 89600 Vector Signal Analyzer application, and set the range to the setting determined in the Spectrum Analyzer application. To do this, you can either use the menus (Input > Range), or you can just click the Range hotspot at the upper right corner of the trace and edit the range value there. Click once to select the value to edit, then click twice to open the value edit dialog box or use the mouse wheel or the keyboard arrow keys to change the value.

To examine a particular portion of the signal (such as a sideband), adjust the frequency span or center frequency, but do not change the range setting.


About Resolution Bandwidth

Menu Path: MeasSetup > ResBW

Resolution bandwidth (ResBW or RBW) determines:

•	The analyzer's frequency resolution.

•	How fast the analyzer makes a measurement (because ResBW affects sweep time).

You can manually enter a resolution bandwidth from the MeasSetup menu by clicking ResBW and modifying the value in the ResBW box. The analyzer will select the viable setting closest to the value you enter.

Because resolution bandwidth also affects sweep time, manually selecting a narrower resolution bandwidth can slow down a measurement more than necessary. Selecting a resolution bandwidth that is too wide, on the other hand, may not provide adequate resolution and can obscure spectral components that are close together.

Note

Swept analyzers specify ResBW (also called window BW in swept analyzers) as the 3 dB bandwidth. This analyzer specifies ResBW as the "equivalent noise bandwidth," which is the bandwidth of a brick-wall filter that passes the same noise power with white noise input.

See also

How ResBW Interacts With Other Parameters

Minimum and Maximum ResBW

ResBW Tab (MeasSetup)

ResBW Mode

ResBW Coupling


Minimum and Maximum ResBW

Menu Path: MeasSetup > ResBW

The minimum and maximum values for ResBW depend on these parameters:

•	The application being used (Spectrum Analyzer application or Vector Signal Analyzer application)

•	Window Type

•	Number of frequency points

•	Span

•	Result length (for digital demodulation measurements only)

•	Symbol rate (for digital demodulation measurements only)

Therefore, changing the result length or the symbol rate changes the resolution bandwidth.

Spectrum Analyzer Application

The minimum and maximum ResBW for the Spectrum Analyzer application is determined by these parameters:

•	Window Type

•	Number of frequency points

•	Span

To determine the minimum and maximum ResBW for your analyzer, click the RBW hotspot in the display and use the keyboard up/down arrow keys or the mouse wheel to scroll through the available settings.

See also

About Resolution Bandwidth


How ResBW Interacts With Other Parameters

(Vector Signal Analyzer application only)

ResBW is related to the time-record length, and windowing function selected, as follows:

where	ENBW = normalized, equivalent noise bandwidth.
RBW = the resolution bandwidth.
 	T = the time-record length.

The equivalent noise bandwidth is a constant; therefore, changing RBW changes the time-record length, and vice-versa. If time gating is off, changing RBW changes the length of the main time-record. If time gating is on, changing RBW changes the length of the gate time-record.

One parameter that limits the minimum and maximum RBW is span. Normally, the analyzer automatically adjusts RBW as you select different frequency spans. However, you can select fixed RBW coupling if you want RBW to remain constant (fixed) as the frequency span changes.

Note

The analyzer displays "DATA?" when RBW is greater than span X 0.043. For details, see DATA?.

See also

About Resolution Bandwidth


ResBW Tab (MeasSetup)

Menu Path: MeasSetup > ResBW

The ResBW tab contains parameters related to resolution bandwidth. In addition, this tab lets you choose a windowing function for spectral measurements.

•	ResBW: Lets you view or change the resolution bandwidth.

•	ResBW Mode: Determines the values you can enter for resolution bandwidth.

•	ResBW Couple: Determines how resolution bandwidth is coupled to frequency span.

•	Window Type: Lets you view or change the windowing function used for spectral measurements.

See also

About Windowing


Frequency Points

Menu Path: MeasSetup > ResBW

The analyzer lets you specify the number of unaliased frequency points to "plot" on the display. You can display from 51 to 102401 frequency points. The default is 801 frequency points. The higher the number, the better the resolution, as shown by the following formula:

The value you enter for the number of frequency points affects the following parameters:

•	Resolution bandwidth

•	Maximum time-record length

•	Measurement speed

Spectrum Analyzer Application

You modify the frequency points from the ResBW tab (click MeasSetup, ResBW). With the Spectrum Analyzer application, the ResBW tab contains the additional check box Same as display.

If you select the Same as display check box, you cannot change the frequency points. In this case, the number of frequency points matches the width (pixels) of the displayed window. If you change the width of the window, the number of frequency points automatically changes to match the new width.

Digital Demodulation

In Digital Demodulation, you cannot change the number of frequency points. Instead, the analyzer automatically determines the smallest number of frequency points needed to compute the measurement data, and shows you this number in the frequency points parameter.

Note

When you turn Digital Demodulation off, the analyzer restores the frequency points parameter to its original value (the original value is the value before selecting Digital Demodulation).

See also

FFT Terminology


ResBW Mode

Menu Path: MeasSetup > ResBW

Your choice of resolution-bandwidth mode in conjunction with your choice of resolution-bandwidth coupling mode affects both resolution and speed (for Spectrum Analyzer measurements, ResBW mode and ResBW coupling affect resolution, but do not affect measurement speed)

Agilent 89600 series analyzers offer two levels of flexibility in selecting a resolution bandwidth setting: 1-3-10 and arbitrary. The first, 1-3-10, is the more restrictive. In this mode the analyzer always sets the resolution bandwidth at a 1 X 10^x or 3 X 10^x value (emulating many existing spectrum analyzers). The arbitrary mode allows arbitrary setting of resolution bandwidth. Your choice of bandwidth mode in conjunction with your choice of ResBW coupling mode affects both resolution and speed. To get the best resolution-to-speed tradeoff, specify auto ResBW coupling and arbitrary ResBW mode.

See also

ResBW Coupling


ResBW Coupling

Menu Path: MeasSetup > ResBW

ResBW coupling determines how resolution bandwidth (ResBW) is coupled to the frequency span. You can select auto coupling, offset coupling, or fixed coupling.

•	Auto selects auto coupling. This coupling selects a ResBW that provides the best compromise between measurement speed and frequency resolution when you change the frequency span. The analyzer chooses the minimum ResBW value that is consistent with the span, ResBW mode, window, and number of frequency points.

•	Offset selects offset coupling. This coupling attempts to maintain a fixed rbw-to-span ratio when you change the frequency span (see below for details).

•	Fixed selects fixed coupling. This coupling does not change ResBW when you change the frequency span. Fixed coupling is automatically selected if you change the value of Main Time Length or if you turn on time gating. This is necessary to maintain the selected value of Main Time Length or Gate Length.

Notes

When time-gating is on, you cannot select auto or offset coupling. The analyzer always uses fixed coupling when time gating is on.

Remember, ResBW is always coupled to the window and the number of frequency points. Auto and Offset coupling, in addition, couple it to span.

Changing RBW Coupling

You can easily override the current resolution bandwidth selection by manually entering a setting of your own. If you override a current resolution bandwidth setting, the analyzer remembers the adjustment you made in terms of a resolution bandwidth to span ratio. The analyzer attempts to maintain this ratio when calculating appropriate resolution bandwidth for different spans. This is called offset coupling.

For example, if you changed to a narrower resolution bandwidth than the default (the resolution bandwidth selected automatically), the analyzer maintains a narrower-than-normal resolution bandwidth for subsequent spans. You can also specify this type of coupling by selecting offset coupled. This type of coupling allows the response to appear the same as the span is changed.

With offset coupling, the analyzer attempts to maintain a fixed rbw-to-span ratio. When ResBW Mode is arbitrary, the ratio is exactly maintained. When ResBW Mode is 1-3-10, the ratio cannot be exactly maintained because ResBW is rounded up to the next 1-3-10 value. Instead, the analyzer calculates offset as follows:

See also

ResBW Mode

About Windowing


About Recordings

(Vector Signal Analyzer application only.)

Menu Path: Input > Recording

The Vector Signal Analyzer application lets you record time data from your VXI hardware directly to your PC's disk drive. You can play the data back at a later time or import it into other applications. You can also create and play your own recording.

The following block diagram is a portion of that shown in the Vector Signal Analyzer Block Diagram. It shows how recording fits into the overall block diagram.

See also

Recording Data

Playing Recorded Data

For information on recordings with non-VXI measurement hardware, see Set up Other Measurement Hardware for a link to your specific hardware.


Creating a Recording

(Vector Signal Analyzer application only.)

1.	Menu Path: Control > Record
OR
Record button on the Control toolbar

1.	Click Control (from the main menu).

2.	Click Record.

CAUTION

Recordings are saved in a temporary recording file, which is overwritten when you create a recording. If you want to preserve the current recording, you must save the temporary recording file before you create a new recording.

Recordings are 50 records by default. The length of a record is the amount of time (number of points) needed to accumulate one average at the current measurement setup. The maximum length of a recording is determined by the amount of memory in your VXI hardware's sample memory (sometimes called capture RAM).

The Record tab (click Input > Recording) lets you enter the recording length in number of records, points, or seconds. The recording length must be greater than zero. If you enter a number that is zero or less, the number you entered is changed to 10, in the units that you specify.

Note

You can enter very small numbers to create a recording. However, when you play the recording, the analyzer may display "Recording not long enough for current measurement" if the recording does not have enough points to fill a time record. This error can happen if you enter less than 1 record as the recording length.

By default, recordings are saved to the following file:

Program Files\Agilent\89600 VSA\Vector\Data\Recording.sdf

The analyzer appends a numeric suffix to the file. This prevents multiple instances of the software from overwriting each other's recording file.

Tip

Click Input > Recording to display the Recording dialog box. This dialog box contains 3 tabs: Record, Info, and Play. The Record tab lets you change the length of the recording and the default filename. The Info tab contains information about a recording, such as its length, the center frequency and span used to create the recording, and whether the recording contains data for 1 or 2 channels. The Playback tab lets you set parameters that control how a recording is played.


Creating A Recording Using an ASCII Editor

(Vector Signal Analyzer application only.)

You can create a recording file using an ASCII editor. To do this, your recording file must be formatted as described in File Format of Recorded Data. The header of the recording file must contain at minimum the following header variables:

•	XDelta

•	InputZoom

•	InputCenter

Note

If you create a recording file that contains data for two channels, make sure arrays Y1 and Y2 contain the same number of points. If you recall a recording file where Y1 and Y2 differ, the application truncates all excess points in the larger array.

The 89600 software can resample your data so that the sample rate to span ratio matches what the 89600 algorithms expect. To turn on this functionality, specify the InputSpan in the Data Header.

Tip

An easy way to learn the structure of a recording file is to create a recording, and then save it as an ASCII file (.txt or .csv). You can then view the recording file with any ASCII editor.


Playing a Recording

(Vector Signal Analyzer application only.)

1.	Create a recording or recall recorded data.

2.	Play the recording:

a.	Click the Restart button on the Control toolbar.

OR

b.	Click Control (from the main menu) > Restart.

3.	Set up Playback Trigger, if necessary.

Tips

•	You can also use the Player to play a recording. The Player also contains controls and indicators that make it easy to view recorded data. For details, see online help for Player.

•	You can use different values for overlap processing to control the speed of the playback. Higher values slow the playback, lower values increase playback speed.

Corrections and Playing a Recording

If Apply Corrections to Data is selected, time-domain corrections are applied permanently to recordings as they are saved in any file format except SDF (Fast) format. This includes any calibration that was selected by the user at the time the signal was recorded. Correcting in this manner allows the user to save fully-corrected data for further processing using MATLAB or other mathematical software. When you recall and playback a recording, the current self-calibration and external corrections are not applied. The External Amplitude tab and External Frequency tab calibration parameters are disabled (greyed-out) during recording playback.

For recordings saved in SDF (Fast) format, the data is saved uncorrected, but correction data is saved with the time data. This correction is applied when you playback the time data. The Amplitude tab and Frequency tab calibration parameters are disabled (greyed-out) during recording playback.

For more information, see Apply Corrections to Data.

Ch1+j*Ch2 Measurements and Playing back a Recording

Signals that are recorded in I+jQ mode should be played back in I+jQ mode. While they can be played back as 2 separate channels, the time corrections will not in general be consistent. 2-channel Baseband recordings, however, can be played back in I+jQ mode and time corrections will be accurate.

Using Overlap Processing On a Digitally Pulsed Signal

If you are playing back a pulsed, digitally modulated signal and using digital demodulation with pulse search to demodulate the signal, note that overlap processing uses the search length to determine the amount of overlap, not the result length. The search length determines how much data is collected whereas the result length determines how much data is demodulated and displayed.


Saving a Recording

(Vector Signal Analyzer application only.)

Follow these steps to save a recording:

1.	Click File (from the main menu) > Save > Save Recording.

2.	In the resulting dialog box, select a file format and enter the filename (including path if necessary). You can save a recording using any of the file formats documented under Saving and Recalling Recordings.

3.	Click Save.

When you click Save, the application copies the temporary recording file (as indicated by Temporary File on the Record tab) to the filename that you specify in the format that you specify.

4.	For all file formats except SDF, the Save Options dialog box allows you to specify these 3 things:

a.	Save header information with data.

b.	At measurement center/span

If this is checked, the recording is saved with the current center frequency and span rather than the center frequency and span at the time the recording was made.

c.	Between playback start/stop time.

If this is selected, the data saved is only the data between the start time and stop time specified in recording playback. Be aware that the data may be slightly less than specified if calibration is on or if the span is not a cardinal span.

Corrections and Saving a Recording

If Apply Corrections to Data is selected, time-domain corrections are applied permanently to recordings as they are saved in any file format except SDF (Fast) format. This includes any calibration that was selected by the user at the time the signal was recorded. Correcting in this manner allows the user to save fully-corrected data for further processing using MATLAB or other mathematical software.

For recordings saved in SDF (Fast) format, the data is saved uncorrected, but correction data is saved with the time data. This correction is applied when you playback the time data.

For more information, see Apply Corrections to Data.


Recalling Recorded Data

(Vector Signal Analyzer application only.)

Follow these steps to recall a recording:

1.	Click File (from the main menu) > Recall > Recall Recording.

2.	In the resulting dialog box, enter the filename that contains your recording.

3.	Click Open.

CAUTION

Recordings are put in a temporary recording file, which is overwritten when you recall a recording. If you want to preserve a previous recording, save the temporary recording file before you recall a recording.

When you click Open, the analyzer copies your file to the temporary recording file shown on the Record tab, overwriting the temporary recording file if it exists. The temporary recording file is always in SDF format, so the analyzer converts your file to SDF format if necessary. After the temporary recording file is recalled, the analyzer automatically selects Input > Data From > Recording.

If the recording you recall is an E3238S snapshot file, the analyzer does not copy the file into the temporary recording file because of the large file size. Instead, the analyzer plays back the original file. For this reason, you must not move an E3238S file while it is being used by the analyzer.

Tip

The Info Tab contains information about a recording, such as its length, the center frequency and span used to create the recording, and whether the recording contains data for 1 or 2 channels.

Filter Settling

If you recall a recording from a CSV, MAT, or TXT file, the analyzer uses some of the points at the beginning of the recording to settle measurement filters. You can minimize this effect by turning off Apply Corrections to Data. (The corrections are already applied to the data when you save the recording in these formats.) Even with corrections turned off, approximately 27 points at the beginning of the data are used to settle measurement filters.

Corrections and Recalling a Recording

For all file formats except SDF(Fast) format, the time-domain corrections are applied permanently to recordings as they are saved. Thus, the recalled signal contains corrected signal data and the current self-calibration and external corrections are not applied.

For recordings saved in SDF (Fast) format, the data is saved uncorrected, but correction data is saved with the time data. This correction is applied when you playback the time data.

For more information, see Apply Corrections to Data.


Using the Player

(Vector Signal Analyzer application only.)

Menu Path: Control > Player

The Player is a graphical tool that helps you play recordings. You click Control > Player to display the Player.

Note

the message "recording is not saved" in the title bar is a reminder that the temporary recording file has not been saved. If you want to be able to use the recording again later, you must save the recording.

On the Player, the area that contains the graphical slider bar represents the length of the recording. As you play the recording, a slider moves left to right to indicate the relative position in the recording. You can grab the slider with the mouse and position it anywhere in the recording. The text box in the lower right corner shows the location of the slider (in seconds).

The first 3 buttons are identical to the Restart, Pause, and Record buttons on the Control toolbar. The remaining buttons control the recording as follows:

	The Back-to-Start and Forward-to-End buttons position the slider at the beginning or end of the recorded data.
	The Previous and Next buttons move the slider back or forward 1 record.
	The loop button controls operation during playback when the recording ends. Clicking this button is identical to clicking the "Loop at end of Recording" on the Playback tab. When the loop button is selected, the recording plays continuously, looping to the beginning when it reaches the end. When the loop button is unselected, playback stops when the recording ends.
	The Start Time and Stop Time buttons let you change the playback's start and stop times. By default, the start time is zero and the stop time is the end of the time record. Clicking either button sets the corresponding start or stop time to the value of the slider. The values of these buttons are identical to those shown under "Start Time:" and "Stop Time:" on the Playback tab. Note that you can reset both values by clicking the Playback tab's Full Time button.
	The arrow keys at each end of the slide bar move the slider .01% of the full recording length.
	Clicking in the slider bar on either side of the slider moves the slider .1% of the full recording length.
See also

Playback tab

Playing a recording


File Format of Recorded Data

The procedures under Saving a recording show you how to save a recording. You can save a recording using any of the file formats documented under Saving and Recalling Traces.

All recording files contain a header and one or two arrays. The header contains a list of variables that describe the recording. The array(s) contain the captured data. There is a single array (Y) if the recording contains data for a single input channel. There are two arrays (Y1 and Y2) if the recording contains data for two input channels.

Tip

When you use the application to create a recording, the selection under Input, Channels (from the main menu) determines whether the recording captures data from one or two channels. Two channel recordings are only available in 89610 analyzers that have the optional second input channel.

The header in a recording file contains some of the same variables found in a trace file. To see the header variables used in a recording file, save the recording as an ASCII file (.txt or .csv) using the procedures in Saving a recording. Then view the recording file with an ASCII editor. For an overview about the data header and details about each header variable, see About the Data Header.


Recording Dialog Box

(Vector Signal Analyzer application only.)

Menu Path: Input > Recording

The Recording dialog box lets you set up the analyzer to record data, play recorded data, or display information about recorded data.

•	Record Tab: lets you set the length of the recording and change the default filename.

•	Playback tab: lets you set parameters that control how a recording is played.

•	Info Tab: contains information about a recording, such as number of channels, length of recording, and the center frequency and span for the recording.

See also

Recording Overview


Record Tab (Recording)

(Vector Signal Analyzer application only.)

Menu Path: Input > Recording > Record tab

The Record tab lets you set the length of a recording and change the default filename.

Length

You can set the recording length in points, records, or seconds. The length of a record is the time (amount of points) needed to accumulate one average at the current measurement setup. To playback a recording, the recording must contain at least 1 record.

The size of sample memory (sometimes called capture RAM) in your ADC hardware determines the maximum length that you can record. Recordings are 50 records by default. Selecting the Max Length check box sets the recording length to the largest possible value.

Temporary File

The Temporary File text box shows the default filename that is used when you save a recording. The temporary recording file is always saved in SDF (Standard Data Format) format. By default, recordings are saved to the following file (clicking the Default File button sets the temporary file to this file) :

Program Files\Agilent\89600 VSA\Vector\Data\Recording.sdf

The analyzer appends a numeric suffix to the file. This prevents multiple instances of the software from overwriting each other's recording file.

See also

Creating a recording


Playback tab (Recording)

(Vector Signal Analyzer application only.)

Menu Path: Input > Recording > Playback tab

The Playback tab lets you set parameters that control how a recording is played.

•	Start Time and Stop Time show the playback's start and stop times. By default, the start time is zero and the stop time is the end of the time record. You can reset both values by clicking the Full Time button.

•	Loop at end of Recording controls playback operation when the recording ends. Selecting this box causes the recording to play continuously, looping to the beginning when it reaches the end. When the check box is cleared, playback stops when the recording ends.

•	The Full Time button resets Start Time and Stop Time to their default values.

See also

Using the Player


Info Tab (Recording)

(Vector Signal Analyzer application only.)

Path: Input > Recording… > Info tab

The Info tab contains information about the currently loaded recording, such as number of channels, length of recording, and the center frequency and span for the recording. See Creating a recording or Recalling recorded data to learn how to load a recording.

•	Recalled Recording File: if you recalled the recording from a file, this text box shows the file's path and filename.

•	Channels: shows the number of channels contained in the recording.

•	Length: shows the length, in seconds, of the recording.

•	Center: shows the center frequency used to create the recording.

•	Span: shows the span used to create the recording. When you play back the recording, you can use a different span, but there are some limitations. See Frequency Span for more information.

•	Time Data: indicates whether the recording contains zoomed or baseband data.


Playback Trigger Tab (Recording)

(Vector Signal Analyzer application only.)

Menu Path: Input > Playback Trigger tab

The Playback Trigger tab lets you set up triggering when playing recorded data. The same trigger parameters available to you when triggering from hardware are available to you when playing a recording, except for the trigger types and trigger holdoff. The trigger conditions of slope, level, delay, and trigger holdoff share the same operation as their identical parameters under the Input, Trigger menu, with the exception that holdoff is available for all playback trigger types except Freerun.

When playing a recording, you can select from the following trigger types. (If a particular trigger type is not available for the recorded data, that type does not appear in the menu.)

•	Free Run selects free-run triggering. This means that the analyzer will process time records as quickly as possible, without waiting for any kind of triggering signal. (Some analyzers call this continuous triggering.)

•	Channel selects an input channel as the trigger signal. The measurement begins when the signal on the selected input channel meets the requirements set by slope, level, delay, and hold-off. Note that although channel trigger is available for all recordings, it is really only useful for baseband data.

•	IF Mag triggers the measurement when the magnitude of the envelope changes. IF Mag is usually used with amplitude modulated (AM) signals. Magnitude trigger triggers the analyzer when the playback signal is within the current span, AND the playback signal is varying in amplitude, AND the trigger conditions (slope, IF Mag level, and delay) are met. IF Mag is unavailable if the measurement is baseband (IF Mag is available only when the measurement is zoomed). For an explanation of baseband and zoomed measurements see Time Data.

•	Magnitude is like IF Mag in that it triggers the measurement when the magnitude of the envelope changes. Magnitude trigger is usually used with amplitude modulated (AM) signals. Magnitude trigger triggers the analyzer when the playback signal is within the current span, AND the playback signal is varying in amplitude, AND the trigger conditions (slope, mag level, and delay) are met. Magnitude trigger is unavailable if the measurement is zoomed (Magnitude trigger is available only when the measurement is baseband). For an explanation of baseband and zoomed measurements see Time Data.

Playback triggering is done from the data before filtering. This is different from Magnitude or IF Mag triggering on data directly from hardware, as shown in the following illustration.\

Note

With IF Mag or Magnitude triggering, the magnitude of the playback signal must vary to trigger the analyzer. The magnitude of the playback signal varies when it switches on and off or if it is AM modulated.

See also

Trigger Overview

Trigger Holdoff

Level (trigger)

Delay (trigger)


About Save and Recall

Menu Path: File > Save or File > Recall

From the main menu, click File > Save or File > Recall to save or recall the following information:

Save	Recall
Instrument Setups	Instrument Setup
Menus/Toolbars	Menus/Toolbars
Display Appearance	Display Appearance
User Color Map	User Color Map
Trace Data	Trace Data
Recordings	Recordings
	State Definitions
See also

Saving and Recalling Instrument Setups

Saving and Recalling Menus and Toolbars

Saving and Recalling Display Appearance

Saving and Recalling User Color Maps

Saving and Recalling Traces

Using Data Registers

Recalling Recorded Data

Saving a Recording

View State Definitions


Recalling a Trace into a Data Register

You can recall any saved trace into a data register (to learn how to save a trace, see Saving and Recalling Traces), as follows:

1.	From the File menu, click Recall > Recall Trace.

2.	In the resulting dialog box, select the trace that you want to recall.

3.	Click Open, which displays the following dialog box.

4.	Select a data register (D1, D2, ... D8) to hold the trace.

5.	Select the Display Data Register check box if you want to display the contents of the selected data register in the active trace.

Note

If you select Display Data Register, the contents of the data register will replace the active trace when you click OK (in the next step).

6.	Click OK.

Note

You can save traces with or without a data header. If you intend to recall a trace, make sure you save it with the data header. The data header includes settings the analyzer needs to correctly recreate the saved waveform (such as resolution bandwidth, windowing function, and X and Y units).

See also

Using Data Registers


Saving and Recalling Display Appearance

Menu Path: File > Save or Recall > Display Appearance

The appearance of the display is highly configurable, including everything from the visibility of the grid, font sizes and colors, to the layout of the traces. To make it easy to replicate these settings, the File > Save and Recall menus include selections to save and recall the overall look of the display.

Along with the ability to save and recall a particular instrument setup and sets of menus and toolbars, it is possible to save and later reconstruct a very particular look and feel for the application.


Saving and Recalling Menus and Toolbars

Menu Path: File > Save or Recall > Menu/Toolbars

Like the overall display appearance, the menus and toolbars are highly configurable. Individual items can be added to or removed from the menus, menus can be reorganized and rearranged limitlessly, and you can add any number of toolbars with a variety of functions and capabilities included. To make it easy to replicate these settings, the File menu provides selections to save and recall the overall look of the display's menus and toolbars.

The settings are stored in the Data directory under the name you provide, with a TOL extension.

Note

You cannot recall menus and toolbars saved from software version A.01.00 into later versions of the software.

Along with the ability to save and recall a particular instrument setup and the overall display appearance, it is possible to save and later reconstruct a very particular look and feel for the application.


Saving and Recalling Instrument Setups
Saving and Recalling Setups

Menu Path: File > Save or Recall > Setup

A complete instrument setup (measurement state) potentially includes a great many items, including the demodulation mode, range, frequency, trigger type, resolution bandwidth, and many other settings and parameters that taken together prepare the instrument to take a particular set of measurements. To make it easy to replicate these settings, the File > Save and Recall menus include selections to save and recall instrument settings.

Along with the ability to save and recall a particular screen appearance and sets of menus and toolbars, it is possible to save and later reconstruct a very particular look and feel for the application.

The measurement state includes the following information:

•	All DISPLAY Group parameters except Math.

•	All MEASUREMENT Group parameters.

Note

The measurement state does NOT include math functions, data registers, or trace data.


Saving and Recalling Traces

Menu Path: File > Save or Recall > Trace

Information about saving and recalling traces is located in the Sharing Data With Other Products and Applications portion of online help, under this topic: Saving and Recalling Traces.


Saving and Recalling User Color Maps

You can save and recall User Color Maps individually with the file extension UCM.. User Color Maps are also saved as part of the display appearance.

To save a color map, click File, Save, Save User Color Map. To recall a color map, click File, Recall, Recall User Color Map.

You can also recall user color maps that were saved from the Agilent E3238 Signals Development System. Those color maps are limited to 32 colors.

User color maps are used for spectrogram displays.


Using Data Registers

The analyzer provides 8 data registers for storing and retrieving trace data. You can perform the following operations with data registers:

•	Copy a trace into a data register.

•	Recall a saved trace (from disk) into a data register.

•	Display the contents of a data register.

•	Remove a data register.

Note

You cannot directly save a data register. To save the contents of a data register, click Trace > Data > Register to display the contents of the data register, then save the trace as usual (click File > Save > Save Trace).

To copy a trace into a data register

1.	From the File menu, click Copy Trace.

2.	In the resulting dialog box, select a data register.

3.	Click OK.

To display the contents of a data register

1.	From the Trace menu, click Data.

2.	From the resulting menus, click Register and select the data register.

Tip

You can also doubleclick the trace title to select the Register trace data. For details, see Selecting Trace Data.

To remove a data register

1.	From the File menu, click Remove Register.

2.	In the resulting dialog box, select the data register that you want to remove.

3.	Click OK.

See also

Register (trace data)

Recalling a trace into a data register


Time Tab (MeasSetup)

(Vector Signal Analyzer application only.)

Menu Path: MeasSetup > Time

The Time tab gives you access to time-domain and time gating parameters. The time-domain parameters are:

•	Main Time Length: Sets the length of the main time record.

•	Max Overlap (Avg Off): Sets the overlap percent used when averaging is off.

•	Max Overlap (Avg On): Sets the overlap percent used when averaging is on.

•	Auto Time Resolution, when selected, causes the analyzer to automatically adjust the span if you enter a Main Time Length that exceeds that allowed by the current span.

The time-gating parameters are:

•	Gate: When selected, turns on time gating.

•	Length: Determines the length of the gate time-record.

•	Ch1 Delay: Determines the gate delay for the channel 1 gate time-record.

•	Ch2 Delay: Determines the gate delay for the channel 2 gate time-record.

•	Window Type: Determines the windowing used to derive gated, spectral displays.

•	Same As Main: When selected, locks the windowing function for the gate time record to match that of the main time record.

See also

Overlap Processing

Main Time Trace Data

Gate Time Trace Data

Vector Block Diagram

About Time Gating


Main Time Length

(Vector Signal Analyzer application only.)

Menu Path: MeasSetup > Time

The Main Time Length parameter determines the length of the main time record. By default, the time-record length (called main time length or main length) is limited by the frequency span and number of frequency points. If you enter a value for Main Time Length that exceeds that allowed by the current span and number of frequency points, the analyzer sets main length to its limit. To increase the value of main length, you must first reduce the span or increase the number of frequency points.

Tip

Select the Auto Time Resolution check box if you want to set the Main Time Length directly. With Auto Time Resolution selected, the analyzer changes the span as needed to allow the value that you enter. Below are formulas that show the relationship of span to time-record length.

Time-record length and resolution bandwidth are inversely proportional, as shown by the following formula. Changing main length changes RBW, and vice-versa. When you change main length, the analyzer automatically sets ResBW Mode to arbitrary and ResBW Coupling to fixed to let you:

•	Enter arbitrary values for main length.

•	Change the span without changing main length.

where:	ENBW is the equivalent noise bandwidth
RBW is the resolution bandwidth

Note

When time-gating is on, RBW is related to gate length, not main length. In this case, changing gate length changes RBW, and vice-versa.

Minimum and Maximum Values

The maximum time-record length (the number of points of time data) is limited by the number of frequency points. The sample rate (the rate at which data is digitized and entered into the time record) is determined by span. Therefore, the maximum time record length for a given span is determined by the number of frequency points. Because of this we can see that for a given window type, the minimum resolution bandwidth, while not directly affected by span and number of frequency points, may be limited by these parameters.

Time record size (also called block size or number of time points) is determined by window, span, and resolution bandwidth. But maximum and minimum time record sizes are determined by memory and FFT constraints:

Maximum time record length

The time record length is limited by the number of frequency points and the frequency span.

Where: FP = number of frequency points

Maximum time record size

The time record size is also limited by the number of frequency points.

TP (max) = 2.56 × (FP − 1) (In baseband mode, real data)

TP (max) = 1.28 × (FP − 1) (In zoom mode, complex data)

Therefore:

T (max) = TP (max) × ΔT

Minimum time record length

Minimum time record length is dependent on the resolution bandwidth to span ratio:

RBW (max) = 0.3 × span

See also

Main Time Trace Data

Vector Block Diagram


Overlap Processing

(Vector Signal Analyzer application only.)

Menu Path: MeasSetup > Time > Max Overlap box

Overlap processing lets you overlap time records. With overlap processing, a percentage of data from one time record is reused in the next time record. You can specify different values of overlap processing for averaged and non-averaged measurements.

 Limits: 0% to 99.99%

You specify the amount of overlap as a percentage. For example, an overlap of 0% does not overlap time records. An overlap of 50% overlaps the time records by half--in other words, the first half of the time record contains data from the last half of the previous time record, as shown below. An overlap of 99.99% (the maximum allowed) overlaps all points except the last point in the time record (this is not true for large time records).

Note

Overlap processing may not be available for non-VXI measurement hardware. To find out if your measurement hardware supports overlap processing, see Setup Other Measurement Hardware for a link to your specific hardware.

Average and Non-Averaged Measurements

The analyzer lets you specify separate overlaps for averaged and non-averaged measurements. Click MeasSetup > Time and use the Max Overlap (Avg On) box to set the overlap for averaged measurements; use Max Overlap (Avg Off) to set the overlap for non-averaged measurements. A value of 0% is the same as turning overlap processing off.

The analyzer uses the value that you set to determine the maximum potential overlap. Overlap processing can dramatically reduce the time needed to compute RMS averages with a given variance.

Recall that window functions reduce the effects of leakage by weighting the ends of the time record to zero. Overlapping can eliminate most (if not all) of the time that would be wasted taking this data. Because some overlapped data is used twice, more averages must be taken to get a variance that is comparable to the non-overlapped case.

Availability

The following table shows you the configurations that support overlap processing. Overlap processing is disabled if the conditions in the table are not met.

This must be selected:	This must NOT be selected:
Free run trigger	Spectrum Analyzer application
	Single Sweep
	Signal Tracking
	Frequency Counter
Maximum Overlap

The overlap percentage that you enter is the maximum potential overlap. The analyzer attempts to achieve the overlap that you specify. However, the actual percentage that the analyzer achieves is determined by the amount of time it takes for the analyzer to process a time record.

The analyzer must be operating in real time to achieve overlap processing. In real time, time records are contiguous (in other words, there is no gap between the end of one time record and the beginning of the next). Real time occurs when the processing time is less than or equal to the time- record length.

Hint

For spectrum measurements, the frequency span at which the processing time equals the time record length is called the real-time bandwidth (RTBW).

The following illustrations show the analyzer operating in real time, and the analyzer operating out of real time. In these illustrations, the FFT determines the processing time.

In the first illustration, the time required to perform the FFT is longer than the time-record length, thus the analyzer is not operating in real time. As shown, the time records are not contiguous and some data is missed while the analyzer finishes computing the FFT.

In the second illustration, the time required to perform the FFT is 20% shorter than the time-record length, thus the analyzer is operating in real time, and the analyzer can achieve up to a 20% overlap.

Processing time depends on the following:

•	Frequency span.

•	Type of average.

•	Number of channels.

•	Number of frequency points.

•	The measurement data being displayed.

•	How busy the analyzer is servicing marker functions and key presses.

•	The speed of your PC's processor and graphics card.

Overlap Processing On Digitally Pulsed Signal

If you are using overlap processing and digital demodulation, and pulse search is on, note that overlap processing uses the search length to determine the amount of overlap, not the result length. Search length determines how much data is collected whereas result length determines how much data is demodulated and displayed.

Note

Digital demodulation is available only in products that have option AYA.


Auto Time Resolution

(Vector Signal Analyzer application only.)

Menu Path: MeasSetup > Time

The Auto Time Resolution check box, when selected, causes the analyzer to automatically reduce or increase the frequency span if the value of main length exceeds that allowed by the current span. This is useful when you want to set main length and let the analyzer choose the time resolution, that is, let the analyzer choose the span.

By default, the value of Main Time Length is limited by the frequency span and number of frequency points. In other words, you cannot change the value of Main Time Length outside of that allowed by the current frequency span.

See also

Main Time Length


About Time Gating

(Vector Signal Analyzer application only.)

Menu Path: MeasSetup > Time

Time gating lets you isolate a portion of a time record for further viewing and analysis. Time gating is often used to analyze non-stationary signals or portions of stationary signals such as burst signals from devices such as videotape recorders, computer disk drives, TDMA communication bursts, or ultrasonic transducers.

Note

You cannot use time gating with digital demodulation.

The following illustration shows how time gating works. The first waveform shows the spectrum of the main time-record. The next waveform shows time-gating applied to the main time-record. The third window shows the spectrum for the gated portion of the main time-record.

When time gating is on, you can identify a portion of the main time-record to be used for frequency-domain displays and CCDF, PDF, and CDF displays. The term "main time-record" identifies the entire time record; the term "gate time-record" identifies the portion selected by the gate.

When time gating is on, the analyzer uses the gate time-record for all frequency-domain displays. That is, spectrum, frequency response, coherence, impulse response, and correlation displays are based on the gate record. For example, if time gating is on and you select a spectrum measurement, the analyzer displays the spectrum of the gate time-record, not the spectrum of the main time-record.

Hint

When time gating is on, the analyzer adds the word "Gate" to the trace title to remind you that the trace is computed from the gate time-record.

See also

Vector Block Diagram

Time Gating Parameters

Important Concepts: Time Gating

Parameter Interactions: Time Gating


Making a Time-Gated Measurement

1.	Start your measurement.

2.	Select the Main Time trace data in any trace. To do this:

Doubleclick the trace title and select Main Time.
OR
From the Trace menu, click Data and choose Main Time.

3.	Turn on time gating and select the desired gate region. To do this:

Click [image] to activate the Gate Marker tool. Then position the Gate Marker tool on the Main Time trace and click the left mouse button. Drag the gate markers to select the desired gate region.
OR
From the MeasSetup menu, click Time, then select the Gate check box to enable time gating. Set Length and Ch1 Delay (Ch2 Delay if Main Time is from channel 2) to select the desired gate region.

4.	In another trace, repeat the procedure in step 2 to select a spectral display. The spectral display is the spectrum of the gate region.

When time gating is on, vertical gate markers appear on the Main Time trace. These markers define the right and left edges of the gate region. Dragging the gate markers changes the gate region, which changes the value of the Time Gating parameters.


Time Gating Parameters

(Vector Signal Analyzer application only.)

Menu Path: MeasSetup > Time

The following parameters are used by time-gated measurements. From the MeasSetup menu, click Time to view all Gate parameters and the Main Time Length parameter. From the Input menu, click Trigger to view the Trigger parameters.

Note

You cannot use time gating with digital demodulation.

•	Trigger Parameters (if any)

•	Main Time Length

•	Gate Check box

•	Gate Delay (Ch1 Delay or Ch2 Delay)

•	Gate Length

•	Gate Window Type

Trigger Parameters determine when the analyzer takes data for the main time-record.

Main Time Length determines the width of the main time-record. If your analyzer has two input channels, main length sets the width of the main time-record for both input channels.

Gate Check box turns on time gating.

Gate Delay determines the start of the gate time-record within the main time-record: Ch1 Delay sets the start of the gate time-record for channel 1; Ch2 Delay sets the start of the gate time-record for channel 2. A gate delay of zero places the start of the gate time-record at the beginning of the main time-record.

Gate Length determines the width of the gate time-record. If your analyzer has two input channels, gate length sets the width of the gate time-record for both input channels.

Gate Window Type determines the windowing function used for gated spectral displays. By default, the analyzer uses the same window for gated spectrums that it uses for non-gated spectrums. However, you can use Gate Window Type to choose a different window for gated spectrums.

Tip

From the MeasSetup menu, click ResBW to choose a Window Type for non-gated spectral displays.

Gate Same as Main check box, when selected, locks the gated windowing function to match that used for the main time record. In other words, changing the windowing function for the main time record also changes the windowing function for the gate time record.

Note

Changing the gated windowing function automatically clears the Gate Same as Main check box.

The analyzer collects a record of data the duration of which is defined by Main Time Length, and the position of which, relative to the trigger, is defined by the trigger delay. After the main-time data has been acquired, the analyzer isolates a portion of the main data as the gate record. The duration and position (relative to the start of the main record) of the gate are determined by the gate length and gate delay (respectively).

See also

Making a Time-Gated Measurement

Time Tab (MeasSetup)

Main Time Length


Important Concepts: Time Gating

This topic contains important concepts that you should know when using time gating.

•	When time gating is on, it is on for both input channels. The gate length is identical for both input channels, but you can position the beginning of the gate time record (via Ch1 Delay and Ch2 Delay) in different locations for each input channel. For example, the Ch1 Delay may be 10 ms and the Ch2 Delay 20 ms.

•	When time gating is on, all spectral displays are derived from the gate time record (the word "Gate" is added to the trace title).

•	By default, the windowing function used for gated spectral displays is the same as that used for non-gated displays. To change the windowing function for non-gated displays, click MeasSetup from the main menu, then click the Time tab and modify the Window Type box. To change the windowing function for gated displays, click MeasSetup from the main menu, then click the ResBW tab and modify the Gate Window Type box.

•	When averaging is used on gated measurements:

−	Rms and continuous peak-hold averaging are applied to the spectrum display of the gate, while time averaging is applied to the main time record.

−	For rms and continuous peak-hold averaging, changing any time-gating parameters restarts the average.

•	When time gating is on, averaging is off, and the measurement is paused, you can change the following parameters and not need to acquire new data:

−	gate delay

−	gate length

−	resolution bandwidth (RBW)

−	window

•	You can step the gate delay through the main time data in increments by selecting Ch1 Delay (or Ch2 Delay for channel 2) and using the mouse wheel or the up and down arrow keys.

•	You can increase the Main Time Length by increasing the number of frequency points. Increasing the number of frequency points lets you select a narrower resolution bandwidth, longer time length, or wider frequency span. Alternatively, you can use Auto Time Resolution to couple the frequency span to the time-record length and then increase the time-record length as desired.

•	Resolution bandwidth cannot be independently adjusted in time gating because the resolution bandwidth is determined by the length of the gate time-record, not the main time-record.

•	If you are using gating to estimate the frequency or phase of a signal at a specific point in time you may want to consider using Analog Demodulation instead. With Analog Demodulation you can measure the instantaneous frequency or phase at a point in time, rather than the estimate over the gate interval.

•	After you have acquired main time data, you may reposition or resize the gate without obtaining new main time data. The analyzer will automatically recompute and redisplay the data contained in the modified gate record.

See also

About Time Gating

Time Gating Parameters

Parameter Interactions: Time Gating


Parameter Interactions: Time Gating

The following illustration shows some inherent parameter interactions. The arrows indicate inversely related parameters.

•	When the gate is off, rbw and time length refer to main length. When the gate is on these parameters refer to gate length--when you change gate length you change the resolution bandwidth. This also implies that you cannot explicitly set resolution bandwidth without changing the gate length.

•	When the gate or main length are explicitly set, rbw coupling is set to fixed, and rbw mode is set to arbitrary. This allows time length to be unrestricted−you can set it to any value supported by the current frequency span. If Auto Time Resolution is enabled, the only limit is the maximum frequency span (Auto Time Resolution changes the frequency span as needed when you change the time length).

•	When rms or continuous peak-hold averaging is on, changing trigger delay, gate delay (Ch1 Delay or Ch2 Delay), or gate length will abort any averaging in progress and a new one will start. Changing the gate length when time average is on will not abort the average.

See also

About Time Gating

Time Gating Parameters


About Trace Data

Menu Path: Trace > Data

Selecting the trace data determines the following for the active trace:

•	The data used to create the trace.

•	The measurement calculation used on the data.

Note

The trace data that you select affects only the active trace. Furthermore, the choices available to you vary with instrument configuration, such as the number of channels selected, whether demodulation is enabled and the type of demodulation.

The easiest way to understand how Trace Data works is with a block diagram. The following block diagram shows how the analyzer uses Trace Data to create Trace A (the block diagrams for Traces B, C, and D are identical):

As seen in the block diagram, Trace Data lets you select the data used and the measurement calculation used to create a trace. The data can come from any of the following:

•	One or more input channels.

•	A math-function.

•	A data register.

Hint

You can select different trace data for each trace. For instance, you can display the spectrum of channel 1 in trace A, the results of a math function in trace B, the time-domain waveform of channel 1 in trace C, and the contents of a data register in trace D. Furthermore, coordinates, units, and scaling can be identical for all traces or unique to each trace.

See also

Selecting Trace Data

Available Trace Data


Selecting Trace Data

There are two ways to select the trace data:

•	From the Trace menu, click Data.

•	From the trace display, Double click the trace data label.

Double clicking the Trace Data Label

Double clicking the trace data label shows the Trace Data dialog box, which lets you select trace data for the active trace. In this example, the analyzer is configured for two input channels with analog demodulation on, in which case you can select:

•	Trace data for either channel (Channel 1 or Channel 2).

•	Demodulated trace data for either channel (Channel 1 Demod or Channel 2 Demod).

•	Trace data for two-channels (Cross Channel).

•	Demodulated trace data for two-channels (Cross Chan Demod).

•	Trace data from a data register (Register).

•	Trace data from a math function (Math).

•	No Data, which turns off trace calculations and displays a blank trace.

Selecting Trace Data from the Trace Menu

You can also select trace data by clicking Data from the Trace menu, which displays a menu similar to the one below. The choices are the same as those displayed when you double click the trace data label, except they are listed in menu format instead of in a dialog box.

See also

About Trace Data

Available trace data


Available Trace Data

Menu Path: Trace > Data

Trace data determines the data and measurement calculation used to create a trace. The trace data that you can select varies with application (Vector Signal Analyzer application or Spectrum Analyzer application) and instrument configuration.

The following table shows the trace data available for the basic VSA applications. Optional demodulation types may add new trace data or disable some of these standard trace data. You can find out about the optional trace data at the following topics:

•	Trace Data for Digital Demodulation

•	3G Cellular

−	Trace Data for W-CDMA(3GPP) Demodulation

−	Trace Data for cdma2000 Demodulation

−	Trace Data for TD-SCDMA Demodulation

−	Trace Data for 1xEV-DO Demodulation

•	Wireless Networking

−	Trace Data for OFDM (802.11a and HIPERLAN/2) Demodulation

−	Trace Data for DSSS/CCK/PBCC (802.11b/g)

Trace Data: Spectrum Analyzer Application

Trace Data	Single Channel	Two Channels
PSD	Yes	—
Spectrum	Yes	—
Math	Yes	Yes
Register	Yes	Yes
No Data	Yes	Yes

Trace Data: Vector Signal Analyzer Application

	Single Channel
Trace Data	Analog Demod Off	Analog  Demod On	Two Channels†
Auto Correlation	Yes	Yes	—
CCDF	Yes	Yes	—
CDF	Yes	Yes	—
Correction	Yes	—	—
Gate Time	Yes	Yes	—
Inst Main Time	Yes	Yes	—
Inst Spec	Yes	Yes	—
Main Time	Yes	Yes	—
PDF	Yes	Yes	—
PSD	Yes	Yes	—
Raw Main Time	Yes	Yes	Yes
Spectrum	Yes	Yes	—
Coherence	—	—	Yes
Cross Correl	—	—	Yes
Cross Spectrum	—	—	Yes
Freq Response	—	—	Yes
Impulse Response	—	—	Yes
Math	Yes	Yes	Yes
Register	Yes	Yes	Yes
No Data	Yes	Yes	Yes
† For two-channel measurements, analog demodulation does not affect
 the available trace data.

See also

About Trace Data

To Select Trace Data


Auto Correlation

(Vector Signal Analyzer application only.)

Menu Path: Trace > Data > Ch1 or Ch2 > Auto Correl

Auto Correlation trace data displays the autocorrelation for the selected input channel. Autocorrelation is a form of correlation, a measure of the similarity between two signals.

Note

Auto Correlation is not available when digital demodulation is selected.

Tips

•	Use ac coupling only. Correlation measurements are disturbed by dc offsets in the signal.

•	Some types of averaging may be useful -- rms averaging does not affect correlation measurements, but you can use time averaging to reduce noise, if you can provide a consistent trigger. However, averaging is usually unnecessary to make good correlation measurements.

•	Use appropriate triggering and trigger delays. This is especially true for time averaging.

•	Use a random noise source for delay measurements. Correlation measurements provide the ability to resolve time differences between waveforms that appear to be random.

•	Waveforms on the correlation trace may not appear as they do in the time trace. This is particularly noticeable when you are using correlation to extract synchronous signals from noise. The different shape of some waveforms is a direct result of the mathematical definition of correlation. For example, a correlated square wave appears as a triangle wave. It's important to remember that the period of the waveform is preserved even if the correlation waveform looks different.

•	To avoid wrap-around effects, correlation produces a time record one-half the length of the measurement time-record.

Theory of Operation

Autocorrelation is a form of correlation, a measure of the similarity between two signals. Correlation is performed by multiplying two signals together at each instant in time and summing all the products. If the signals are identical, every product is positive and the resulting sum is large.

If, however, the two signals are dissimilar, then some of the products are positive and some are negative. In this case, the final sum is smaller because the products tend to cancel.

Autocorrelation performs a time-shifted, "averaged" correlation on a single signal. The signal is correlated with time-shifted versions of itself. Furthermore, the products from each time-shift are averaged by dividing each final sum by the number of products contributing to it.

where:	Rxx = autocorrelation function
τ = amount of time shift
∞ = infinity
x(t) = signal to be correlated
intgrl = integration
conj = conjugation
T = time
× = multiplication

That is, the autocorrelation function is found by taking a signal, multiplying it by the same signal displaced (tau) units in time, and averaging the product over all time.

Duality With the Power Spectrum

For simplicity and speed, this analyzer performs the autocorrelation operation by taking advantage of its duality with the power spectrum:

 Rxx(τ) ↔ Gxx(f)

Thus,

Rxx(τ)	= IFFT [Gxx(f)]
= IFFT [conj(F[r × t]) × F(t)]

where:	IFFT = Inverse FFT
conj = conjugation
× = multiplication
r = half size rectangular window (thus the result is 1/2 the original time length)

When to use Auto Correlation

Auto correlation is useful for detecting echoes in a signal. For random noise, an echo appears as an impulse -- if there is more than one echo, you will see multiple peaks on the auto correlation trace. Keep in mind that an echo appears as an impulse only if the delayed signal has not been filtered. The impulse broadens as the original random noise signal is filtered -- in fact, the width of each peak is inversely proportional to the bandwidth of the signal.

To determine the time delay (in seconds) of an echo, you can move the marker to the peak of the echo. Note that there is always a correlated peak at zero lag -- this peak marks the original excitation signal. Any other peaks let you know that the excitation signal also appeared at another time relative to the original signal. The amplitude value at the zero lag point is the total power in the time record.

This function is also useful for isolating low-level periodic signals from noise. A sine wave signal shows up as a sine wave in auto correlation. A square wave signal shows up as a triangular wave of the same frequency.

Auto correlation is a single-channel measurement. If you have the original signal on one channel and the delayed version on another, use cross correlation.

Auto Correlation and Averaging

The following formulas show how the analyzer calculates auto correlation for different averaging functions:

Key:	F = Fast Fourier Transform (FFT)
AC = Averaged correlation
AT = Averaged time
t = Instantaneous time
c = Instantaneous correlation
r = 1/2 width rectangular window
× = multiplication
n = Average number

No Average	c = I (conj (F {r × t} ) × F [t] )

rms Average	c = I (conj (F {r × t} ) × F [t] )

rms Expon.	c = I (conj (F {r × t} ) × F [t] )
 Average

Continuous
 Peak Hold	c = I (conj (F {r × t} ) × F [t] )
 Average

Time	AC [n] = I (conj (F {r × AT [n] } ) × F (AT [n] ) )
 Average

Time
 Expon.	AC[n] = I (conj (F {r × AT [n] } ) × F (AT [n] ) )
 Average

 and: 1 ≤ n ≤ number of averages


CCDF

(Vector Signal Analyzer application only,
Not available with Digital, W-CDMA and cdma2000 demodulation)

Menu Path: Trace > Data > Ch1 or Ch2 > CCDF

CCDF trace data displays the complementary, cumulative density function (CCDF) for the selected input channel.

Overview

The complementary, cumulative density function (CCDF) is a statistical-power calculation and can be performed only on time-domain data. As its name suggests, CCDF is the complement of CDF, and is defined as follows:

 CDF(K) = Probability(x ≤ K)
 CCDF(K) = Probability(x ≥ K)

CCDF provides better resolution than CDF for low probability signals, especially when log format is used for the y-axis.

The analyzer plots CCDF using units of percent (%) for the y-axis and power (dB) for the x-axis. Power on the x-axis is relative to the signal average power, so 0 dB is the average power of the signal. Therefore, a marker readout of

Trace A Marker 2 dB 12 %

means there is a 12% probability that the signal power will be 2 dB or more above the average power.

CCDF Calculation:

1.	Calculate the RMS value for all measured samples; this becomes the 0 dB point at the left end of the x-axis.

2.	Normalize all samples to the RMS value in units of dB.

3.	Determine which x-axis bin each sample belongs in between 0 and 20 dB.

4.	Calculate the total number of samples that are greater than or equal to each x-axis bin and plot as a percent of the number of samples measured.

Samples Used in the Power Measurement

For the Demod Off and Analog demod modes, the analyzer computes CCDF using all samples in the current time record (all points in the active trace). Each successive time record adds additional samples to the CCDF measurement.

For WLAN - OFDM and -DSSS demod modes, the analyzer computes CCDF using all samples specified within the measurement interval.

Restarting the Power Measurement

Selecting CCDF, restarting the measurement, or changing most measurement parameters restarts the CCDF measurement. For example, changing the range or center frequency resets the number of samples used in the CCDF measurement to zero and restarts the CCDF measurement.

Tips

Note the following when making CCDF measurements:

•	For best results, set the analyzer's displayed frequency span to include all the energy of your signal. In other words, make sure the displayed frequency span includes the entire bandwidth of the measured signal.

•	The CCDF measurement does not restart:

−	After a calibration

−	After you continue a paused measurement

•	Many channel specific changes restart the CCDF measurement on both channels, such as changing the gate delay, or input coupling.

•	The analyzer displays DATA? if the average power drifts 8 to 10 dB from the average power measured in the first time record. For example, the analyzer would display DATA? if you measured a transmitter signal that was off when the CCDF measurement started but then turned on later in the measurement.

•	CCDF measurements are disabled during time averaging.


CDF

(Vector Signal Analyzer application only,
Not available with Digital, W-CDMA, cdma2000, or OFDM demodulation)

Menu Path: Trace > Data > Ch1 or Ch2 > CDF

CDF trace data displays the cumulative density function (CDF) for the selected input channel. CDF is computed by integrating the PDF (Probability Density Function). CDF is explained in online help for the CCDF trace data—for further details, see that topic.


cdma2000 Trace Data

For a list of the available trace data for cdma2000, click here


Coherence

(Vector Signal Analyzer application only.)

Menu Path: Trace > Data > ChX > Coherence

Coherence is a two-channel measurement that indicates the similarity between two signals. In transfer functions, it indicates how much of the output power is coherent with the input power. In other words, coherence is a measure of the power in the output signal caused by the input.

Note

Coherence is available only when two input channels are selected (note that the Agilent 89640 analyzer does not support two input channels). Furthermore, Coherence can be calculated only when averaging is on, there are at least 2 averages, and the average type is RMS (video). If averaging is off or the wrong average type is selected, the trace is blank. If you specify only 1 average, Coherence always 1.0 for all frequencies).

Coherence is scaled from 0.0 (complete incoherence) to 1.0 (unity, or perfect coherence). A coherence of 1 indicates all the output power is caused by the input. A coherence of 0 indicates none of the output power is caused by the input.

Thus, coherence less than unity indicates the presence of external extraneous noise, system nonlinearities, or unexpected input signals.

The analyzer calculates coherence as follows:


Correction

(Vector Signal Analyzer application only.)

Menu Path: Trace > Data > Ch1 or Ch2 > Correction

Displays the correction trace derived by the analyzer from the calibration data. The correction trace is applied to the acquired data to compensate for phase and magnitude anomalies in the analyzer's hardware and software signal processing.

The number of points in the correction spectrum varies. The number is affected by the number of time record samples used in a measurement (and therefore by most of the settings on the ResBW dialog) and by the adaptive equalizer settings (when used). The minimum number of points in the correction trace depends on the 89600 software version:

Versions 3.01 and later	minimum 256 points

Versions 3.00 and earlier	minimum 128 points


Cross Correlation

(Vector Signal Analyzer application only.)

Menu Path: Trace > Data > ChX > Cross Correlation

Cross correlation trace data is a two-channel measurement that is most useful for determining time delays of a common signal between two different paths. For example, to determine the speed of sound you could place one microphone at a sound source and another microphone a known distance away. The cross correlation would show a peak at the time delay between the two microphones. It would also show peaks for each path. The width of each peak is inversely proportional to the bandwidth of the signal. For example, random noise produces a very narrow peak.

Note

This trace data is available only when two input channels are selected.

Overview

 Cross correlation is similar to autocorrelation in its derivation:

Ryx(τ)	= IFFT (F(y) × conj [F(x)])

where:	IFFT = Inverse FFT
conj = conjugation
F(x) = FFT of channel 1 data
F(y) = FFT of channel 2 data
× = multiplication

For theoretical information, and for tips, see online help for autocorrelation —the tips and theoretical discussion there also apply to cross correlation.

Cross Correlation and Averaging

The following formulas show how the analyzer calculates cross correlation for different averaging functions:

Key:	F = Fast Fourier Transform (FFT)
AC = Averaged correlation
AT1 = Averaged time, channel 1
AT2 = Averaged time, channel 2
t1 = Instantaneous time, channel 1
t2 = Instantaneous time, channel 2
c = Instantaneous correlation
r = 1/2 width rectangular window
× = multiplication
n = Average number

No Average	c = I (F [t2] × conj (F [r × t1] ) )

 rms Average	c = I (F [t2] × conj (F [r × t1] ) )

rms Expon.	c = I (F [t2] × conj (F [r × t1] ) )
 Average

Continuous
 Peak Hold	c = I (F [t2] × conj (F [r × t1] ) )
 Average

Time	AC [n] = I (F (AT2 [n] ) × conj (F {r × AT1 [n] } ) )
 Average

Time
 Expon.	AC[n] = I(conj(F{r × AT[n]}) × F(AT[n]))
 Average

 and: 1 ≤ n ≤ number of averages


Cross Spectrum

(Vector Signal Analyzer application only.)

Menu Path: Trace > Data > ChX > Cross Spectrum

Cross spectrum trace data (also called cross power spectrum) is a two-channel measurement. Cross spectrum is seldom used as a separate measurement, but is used internally by the analyzer to compute other measurements such as transfer function and coherence.

Note

This trace data is available only when two input channels are selected. It is not available when digital demodulation is selected.

The cross spectrum, Gxy, is defined as taking the FFT of two signals separately and multiplying the results together, as follows:

The exact computation used by this analyzer depends on the type of average used:

If the average is:	the analyzer uses this formula:
None	A
Time	A
Time exponential	A
rms	B
rms exponential	C
Continuous peak hold	cross spec. unavailable
Term	Definition
N	number of averages
linspec1	linear spectrum channel 1
linspec2	linear spectrum channel 2
xavg	(1/N) * new + ((N-1)/N)* old
conj	conjugation


Digital Demodulation Trace Data

You can find a list of the available trace data for digital demodulation at this topic: Trace Data for Digital Demodulation.


Frequency Response

(Vector Signal Analyzer application only.)

Menu Path: Trace > Data > Chx > Frequency Response

Frequency response trace data is a two-channel measurement defined as the output of a device-under-test (DUT) divided by its input (make sure channel 1 is connected to the input of your DUT and channel 2 is connected to its output).

Note

This trace data is available only when two input channels are selected. It is not available when digital demodulation is selected.

The exact computation used for frequency response depends on the type of average used:

If the average is:	the analyzer uses this formula:
None	A
Time	A
Time exponential	A
rms	B
rms exponential	B
Continuous peak hold	Frequency response is unavailable
Formulas:

A: (linspec2) / (linspec1)

B: (cross spectrum) / (power spectrum Ch 1)

Term	Definition
linspec1	linear spectrum channel 1
linspec2	linear spectrum channel 2


Gate Time

(Vector Signal Analyzer application only.)

Menu Path: Trace > Data > Ch1 or Ch2 > Gate Time

Gate Time trace data displays the selected channel's gate time-record.

Note

Gate Time is not available when analog or digital demodulation is selected.

If time gating is on, Gate Time displays the portion of the main time-record marked by the gate-- this portion is called the gate record (if time gating is off, Gate Time displays nothing).

As a reminder, if time gating is on, the Fast Fourier Transform (FFT) uses the gate time-record, which can be all or a portion of the main time-record, to compute frequency information such as spectrum, frequency response, coherence, and correlation.

See also

Main Time

About Time Gating

Making a Time-Gated Measurement


Impulse Response

(Vector Signal Analyzer application only.)

Menu Path: Trace > Data > ChX > Impulse Response

Impulse Response trace data displays the impulse response of a system. The impulse response is the inverse Fourier transform of the frequency response.

Note

This trace data is available only when two input channels are selected. Impulse Response is not available when digital demodulation is selected.

When two-channels are selected, most of the two-channel trace data defines channel one as a stimulus to some system, and channel two as the response from the system to that stimulus. This definition is used to calculate two-channel results such as the frequency response and impulse response of a system.

As mentioned above, the impulse response is the inverse Fourier transform of the frequency response (as shown below). It represents the (idealized) time-domain response of the system to an input signal that is an infinitely narrow impulse.


Inst Main Time

(Vector Signal Analyzer application only.)

Menu Path: Trace > Data > Ch1 or Ch2 > Inst Main Time

Inst Main Time trace data displays the instantaneous time-domain data for the selected input channel.

Note

Inst Main Time is not available when analog or digital demodulation is selected.

The following block diagram is a portion of the Vector Signal Analyzer block diagram. It shows how Instantaneous Main Time is derived.

Notice that Instantaneous Main Time shows you time data before time averaging. If time averaging is off, Instantaneous Main Time is identical to Main Time.

See also

Main Time


Inst Spectrum

(Vector Signal Analyzer application only.)

Menu Path: Trace > Data > Ch1 or Ch2 > Inst Spec

Inst Spectrum trace data displays the instantaneous spectrum for the selected input channel. Instantaneous spectrum is computed before data is averaged, which allows you see spectrum data before the data is averaged with other spectrum data.

Note

Inst Spectrum is not available when analog or digital demodulation is selected.

The following block diagram is a portion of the block diagram shown under Vector Block Diagram. It shows where, in the block diagram, spectrum and instantaneous spectrum are created.

This measurement calculation is useful for these types of averaged measurements:

•	rms

•	rms exponential

•	Continuous peak hold

Hint

If averaging is off, the spectrum and instantaneous spectrum display the same information.


Main Time

(Vector Signal Analyzer application only.)

Menu Path: Trace > Data > Ch1 or Ch2 > Main Time

Main Time trace data displays the selected channel's main time-record.

Note

Main Time is not available when analog or digital demodulation is selected.

Main Time versus Gate Time

The term "main time-record" may be new to you. This term is used to differentiate between the "main" time record and the "gate" time record when time gating is on.

As you may recall, a time record is the basic building block of the Fast Fourier Transform (FFT). The FFT takes the time-domain information in the time record and transforms it into the frequency domain.

When time gating is on, you can identify a portion of the main time-record to be used by the FFT. The term "main time-record" identifies the entire time record; the term "gate time-record" identifies the portion selected by the gate.

Selecting the Main Time trace data displays the entire time record--the main time-record. Selecting the Gate Time trace data displays that portion of the main time-record marked by the gate--the gate time-record.

The following block diagram is a portion of the block diagram shown under Vector Block Diagram. It shows the blocks that create main time and gate time.

Note

The Analog Demodulation block is available only when analog demodulation is enabled

Reasons for Displaying the Time Record

There are many reasons why you may want to view the main time record. Here are just a few:

•	To verify that there is an input signal.

•	To see the characteristics of the input signal.

•	To help in manually setting the input range.

Time Records and Span

If you set the analyzer to full span, the time data you see is the actual input time-record. This is raw input data--the signal from which all subsequent measurements are based.

If you set the instrument to measure a specific bandwidth (something less than full span), the time data you see is the raw input data after it has been filtered (to provide alias protection) and decimated (to obtain the desired span).

Time Records and Averaging

If rms or continuous peak-hold averaging is on, the analyzer displays the most recent time record. The analyzer does not show an averaged time waveform, because all averaging is done after the time data has been transformed to the frequency domain.

If time averaging is on, the analyzer displays the averaged time-record. In other words, the time record has been averaged with previous time records.

How the Analyzer Displays the Time Record

It is important to remember that although the time record looks like an oscilloscope display, the analyzer is not a digital oscilloscope.

The time record represents samples of a waveform. The samples have enough information to accurately reconstruct the input signal--but the human eye may not properly perform the reconstruction. In fact, for frequencies that are higher than about ten percent of the frequency span, there will be noticeable visible distortion.

The analyzer's anti-alias filters will cause some ringing or distortion of square waves or transients when viewed in the time domain.

See also

Gate Time

Inst Main Time

About Time Gating

Making a Time-Gated Measurement


Math

Menu Path: Trace > Data > Math

Math trace data displays the results of the selected math function.

Note

Math trace data is available only if a math function is defined. To learn how to create a math function, see Creating Math Functions.

If you select a math function that cannot be calculated, the analyzer displays a grid with no data. If this happens, examine the math function to determine if your math function is correct. Also examine operands in the math function. Some operands, such as data registers, may have no data.

See also

About Math Functions

Creating Math Functions


No Data

Menu Path: Trace > Data > No Data

The No Data trace data turns off trace computations, which results in a blank trace. No Data lets you increase measurement speed by turning off post-processing calculations for the active trace.

Note

By default, the analyzer always calculates all traces, even if the traces are not displayed.


OFDM Trace Data

For a list of the available trace data for OFDM 802.11a and HIPERLAN/2 , click here


PDF

Menu Path: Trace > Data > Ch1 or Ch2 > PDF

PDF trace data displays the Probability Density Function of the selected channel. PDF indicates the probability that a given level has occurred.

Note

PDF is not available when digital demodulation is selected.

PDF is equivalent to a normalized histogram. A histogram shows how the amplitude of a signal is distributed between its maximum and minimum values. Amplitude is displayed on the X-axis, and number of counts on the Y-axis.

The number of averages for a histogram determines the number of counts in the histogram; in other words, how many records are measured—the records are not "averaged". If averaging is off or if exponential averaging is selected, the measurement continues indefinitely. Keep in mind that the accuracy of the histogram is dependent on the frequency span, time-record length, and number of averages (if averaging is on).

Histograms are used for such things as determining the statistical properties of noise and monitoring the performance of electromechanical positioning systems.

PDF trace data is normalized by multiplying the number of averages by the number of points in the time record, then dividing this value by the ΔV spacing on the X-axis. The probability of a signal falling between two points is equal to the integral of the curve between those points.

PDF trace data displays the number of points used in its computation above the trace (Pts:). It also displays the average level (Avg:) above the trace.


PSD

(Not available with Analog, Digital, W-CDMA, cdma2000, or OFDM demodulation)

Menu Path: Trace > Data > Ch1 or Ch2 > PSD

PSD trace data displays the power spectral density (PSD) of the selected channel.

The definition of PSD yields y-axis units of Vpk^2/Hz and x-axis units of frequency:

 |...
 Vpk^2 | ..
 ----- | .....
 Hz | .
 | ..........
 |_____________________
 Frequency

PSD is used for noise measurements. It shows the power density of a signal as a function of frequency. In general, noise may have any arbitrary frequency content, resulting in a variety of possible PSD shapes. Noise that has equal power density at all frequencies is called white noise:

 | White Noise
 Vpk^2 |
 ---- |.....................
 Hz |
 |
 |_____________________
 Frequency

The definition of PSD is power per Hertz. In other words, power is divided by the measurement bandwidth, which in this analyzer is the resolution bandwidth (ResBW), as follows:

Units of Vpk^2/Hz assumes the signal is referenced to 1 ohm. That is, because no resistance is specified, the signal is interpreted as a voltage across a one ohm resistor, with the power in the resistor equal to Vpk^2.

You can select units of dBm/Hz to take into account the analyzer's input impedance. PSD defaults to these units. The analyzer calculates dBm/Hz as follows:


Raw Main Time

(Vector Signal Analyzer application only.)

Menu Path: Trace > Data > Ch1 > Raw Main Time

Raw Main Time is the raw data read from the input hardware or playback file. It is similar to Main Time with the following exceptions:

•	This data has not had time corrections applied, so it displays a "CAL?" trace LED.

•	The data has not gone through the analyzer's software resampling filters, so is generally not sampled at the specified sample rate.

•	The data has a wider bandwidth than the measurement span would indicate.

Raw Main Time data is useful in the following situations:

•	When you use Channel, IF Magnitude, or Magnitude trigger types, the input hardware detects the trigger, so Raw Main Time sometimes gives a better indication of what caused the trigger.

•	When you play back a recording, the Raw Main Time measurement data allows you to see exactly the samples that are saved in the recording, with no filtering applied or settling removed.


Register

Menu Path: Trace > Data > Register

The Register trace data displays the contents of the selected data register in the active trace. The analyzer displays a blank trace if the data register is empty or if it contains invalid data.

Note

The Register selection on the Trace Data menu is unavailable if all data registers are empty. To learn how to us data registers, see Using Data Registers.


Spectrum

Menu Path: Trace > Data > Spectrum

The Spectrum trace data displays the spectrum of the selected channel. The spectrum computation displays frequency on the x axis and amplitude on the y axis.

The following formulas show how the analyzer calculates spectrum information:

No Average
rms Average
rms Exponential AF[n]Average
Continuous Peak Hold Average
Time Average
Time Exponential Average

As shown in the previous formulas, the spectrum may be a linear spectrum or power spectrum as follows:

If the average is...	then the spectrum is...
Averaging OFF	Linear
rms Average	Power
Continuous peak	Power

Linear spectra contain magnitude and phase (real and imaginary) information. Remember however, that scalar measurements (produced by the Spectrum Analyzer application) do not provide phase information. Therefore, for scalar measurements, linear spectra have no phase information.

Power spectra contain only magnitude (real) information. This occurs with rms averages, for instance, because the results of the FFT are squared. Remember that the FFT yields both real and imaginary information. When the analyzer squares the results of the FFT, the imaginary part becomes zero.


W-CDMA Trace Data

For a list of the available trace data for W-CDMA, click here


About Trace Format

The easiest way to understand how trace format works is with a block diagram. The following block diagram shows how the analyzer uses trace format to create trace A (traces B, C, and D have identical block diagrams):

Note

The selection you make with Trace, Data and Trace, Format determine the units for the x and y axes. For many selections, you can change the y-axis units. To do this, click Trace, Y Scale, and select a different Y unit.


Selecting a Trace Format

Menu Path: Trace > Format

To select a trace format:

1.	On the Trace menu, click Format.

2.	In the Format box, select a trace format. You can select from:

−	Log Mag

−	Linear Mag

−	Real (I)

−	Imag (Q)

−	Wrap Phase

−	Unwrap Phase

−	Group Delay

−	I-Q (Digital Demodulation)

−	Constellation (Digital Demodulation)

−	Q-Eye (Digital Demodulation)

−	I-Eye (Digital Demodulation)

−	Trellis-Eye (Digital Demodulation)

See also

Format tab


Format Tab (Trace)

Menu Path: Trace > Format

The Format tab lets you select coordinates for the active trace.

•	Format: Lets you select coordinates for the active trace, such as Log Mag or Linear Mag.

•	Log X-Axis: Lets you choose a linear or logarithmic scale for the x- axis.

•	Phase Offset: Lets you specify a phase offset when the Trace Format is unwrapped phase.

•	Unwrap Reference: Lets you designate the point (x-axis) value about which phase values are to be unwrapped when the Trace Format is unwrapped phase.

•	Delay Aperture: Determines the aperture setting when the Trace Format is group delay.

See also

Selecting a Trace Format

Selecting Trace Data


Group Delay

Menu Path: Trace > Format > Format box

Selecting the Group Delay trace format displays the group delay for the active trace. By definition, group delay is the derivative (or slope) of the phase response. It's useful for measuring signal transit-time through a device and for measuring the device's phase linearity. The formula for group delay is:

Group Delay = [− delta(ph)/delta(f)] × [1 cycle/360 degrees]

"delta(ph)" is the phase difference (in degrees) of two frequencies separated by delta(f); "delta(f)" is the difference between two frequencies, in Hertz (cycles/second). Dividing by 360 converts degrees to radians. The final units for group delay are seconds.

You can adjust delta(f) by adjusting the group-delay aperture and/or the frequency span, according to the following formula:

delta(f) = (aperture) × (frequency span)

Group Delay in the Time Domain

This analyzer also lets you compute group delay for time-domain data. The same formula is used, except delta(f) is replaced with delta(t), as follows:

Group Delay = [− delta(ph)/delta(t)] × [1 cycle/360 degrees]

−	"delta(ph)" is the phase difference (in degrees) of two points separated by delta(t).

−	"delta(t)" is the difference between two points, in seconds.

−	Dividing by 360 converts degrees to radians.

−	The final units for group delay in the time domain are Hertz.

You can adjust delta(t) by adjusting the group-delay aperture and/or the time-record length, according to the following formula:

delta(t) = (aperture) × (time-record length)

To compute group delay, the analyzer uses complex data. Therefore, for time-domain data, the group delay is flat unless time data] is set to Zoom.

Note

For time-domain traces, group-delay yields y-axis units of Hertz; for frequency-domain traces, group-delay yields y-axis units of seconds.

See also

Group Delay Aperture


Group Delay Aperture

Menu Path: Trace > Format

The value of Delay Aperture (under Trace, Format) is used when the trace format is Group Delay. The aperture is set as a percentage of the current frequency span for frequency-domain data. It is set as a percentage of the time-record length for time-domain data.

When group delay is calculated for a given point (which can be a time- or frequency-domain point), the aperture is centered at that point. Larger apertures decrease resolution, but they increase the smoothing of the group-delay trace.

The point plotted for group delay is located between the data points used to calculate it. For example, in the frequency domain, the group delay for 100 Hz may be calculated by measuring the change in phase between 90 and 110 Hz. If you had specified a start frequency of 90 Hz, 100 Hz would be the first point with group delay data. This results in a trace that does not extend to the edges of the screen (more noticeable as the delay aperture increases).

The following table shows the size of the group-delay aperture in number of bins. For example, if the number of frequency points is 401 and the aperture is 16% of span, the size of the aperture is 64 bins.

Note

The smallest aperture that you can select depends on the number of frequency points. If you select an invalid aperture, the analyzer automatically selects the smallest valid aperture.

 Size of Group Delay in Number of Frequency Bins

	Number of Frequency Points
Aperture	51	101	201	401	801	1601	3201
0.125 %	2	2	2	2	2	2	4
0.25 %	2	2	2	2	2	4	8
0.5 %	2	2	2	2	4	8	16
1.0 %	2	2	2	4	8	16	32
2.0 %	2	2	4	8	16	32	64
4.0 %	2	4	8	16	32	64	128
8.0 %	4	8	16	32	64	128	256
16.0 %	8	16	32	64	128	256	512
	Number of Frequency Points
Aperture	6401	12801	25601	51201	102401
0.125 %	8	16	32	64	128
0.25 %	16	32	64	128	256
0.5 %	32	64	128	256	512
1.0 %	64	128	256	512	1024
2.0 %	128	256	512	1024	2048
4.0 %	256	512	1024	2048	4096
8.0 %	512	1024	2048	4096	8192
16.0 %	1024	2048	4096	8192	16384
Group Delay Aperture and Trace Blanking

When you display Group Delay, the analyzer blanks a portion of the data at the beginning of the trace and at the end of the trace. The width of the blanked area is one-half the value of the Group Delay Aperture setting. For example, if Group Delay Aperture is set to 10%, the first 5% and the last 5% of the trace will be blanked.

See also

Group Delay


Log Mag and Linear Mag

Menu Path: Trace > Format > Format box

Selecting the Log Mag or Linear Mag trace format selects logarithmic- or linear-magnitude data for the active trace. Select Linear Mag to display the trace on a linear y-axis scale. The y-axis value is the square root of (real part squared plus imaginary part squared). Select Log Mag to display the trace on a logarithmic (decibel) y-axis scale.

Characteristics

Here are some characteristics you should know:

•	For Log Mag, all points on the y-axis have a logarithmic relationship (regardless of the vertical unit you've selected).

•	For Linear Mag, all points on the y-axis have a linear relationship (regardless of the vertical unit you've selected).

•	For frequency-domain measurements, frequency is the x-axis.

•	For time-domain measurements (time records), time is the x-axis.

•	For Log Mag or Linear Mag, the offset marker shows the ratio between the marker and the offset marker.


Log X-Axis

Menu Path: Trace > Format

The Log X-Axis check box (under Trace, Format) lets you specify linear or logarithmic x-axis scaling for active trace. When selected, the x-axis uses a logarithmic scale. When cleared, it uses a linear scale.

Note

For Digital Demodulation, eye diagrams or IQ (polar) diagrams automatically select a linear x-axis−you cannot select a logarithmic axis for these trace formats.

Log X-Axis affects only how the data is displayed. For the same span and resolution, frequency resolution for both linear and logarithmic scales is identical—both have the same number of points per display. The logarithmic scale simple displays these points on a logarithmic axis.

If two traces are displayed and one has a linear frequency axis and the other a logarithmic, marker coupling is still a valid choice and the markers will track bin for bin.

When a logarithmic x-axis is selected, frequency annotation is done in terms of start and stop frequency, not in terms of span and center frequency.


Real(I) and Imag(Q)

Menu Path: Trace > Format > Format box

Selecting the Real(I) or Imag(Q) trace format displays the real or imaginary part of the measurement results in the active trace. For Digital Demodulation, Real(I) displays the I component of the IQ waveform; Imag(Q) displays the Q component.

Overview

A trace may comprise real data or both real and imaginary data. Real(I) and Imag(Q) let you look only at the real part, or only at the imaginary part. Both the real part and the imaginary part are displayed on the y-axis, with time or frequency on the x-axis.

Here is some additional information you may need to know:

•	Some trace data is purely real, in which case the imaginary part will be a flat line, showing zero amplitude.

•	For frequency-domain data (the result of the FFT), the imaginary trace represents the imaginary part of the complex FFT data after it has gone through the measurement calculation (see hint below).

•	For time-domain data, the real and imaginary trace represent the data before it has been windowed, but after it has been filtered (by the digital filter), and after corrections have been applied and after time averaging. If time gating is on, the real and imaginary data is the result of time gating (see hint below).

•	For time waveforms, the imaginary trace represents the imaginary part of the Hilbert transform of the real part. For example, a 2 volts peak, sine-wave input in zoom mode appears as a frequency-shifted, 2 volts peak, sine wave in the real part trace, and as a frequency- and phase- shifted 2 volts peak, sine wave in the imaginary part trace.

•	If the ch1 + j*ch2 input is selected, real = Channel 1 data; imaginary = Channel 2 data.


Wrap Phase and Unwrap Phase

Menu Path: Trace > Format > Format box

Selecting the Wrap Phase or Unwrap Phase trace format displays wrapped or unwrapped phase for the active trace. The y-axis unit is either degrees or radians.

Wrapped Phase

Wrapped phase means that all phase is shifted to between -180 degrees and +180 degrees. If the actual phase is outside this range, it is increased or decreased by a multiple of 360 degrees to put it between -180 and +180 degrees.

For example, +400 degrees is displayed as +40 degrees (400 - 360 = 40), and -190 degrees is displayed as +170 degrees (-190 + 360 = 170).

Unwrapped Phase

Unwrapped phase lets you designate a point (x-axis) value about which phase values are to be unwrapped. This point is called the Unwrap Reference. This would typically be a well-known point in a measurement such as the passband of a band pass filter.

When Unwrap Phase is selected, you can also specify a Phase Offset, which offsets the phase trace by the amount of phase shift that you specify. For example, a phase offset of 90 degrees offsets the phase trace by +90 degrees, such that +90 degrees on the phase trace corresponds to 0 degrees.

Phase and Spectrum Measurements

In a spectrum measurement, the usefulness of phase information is often not obvious. Because phase is a relative concept, you may ask "phase with respect to what?"

Phase displayed on an FFT analyzer depends on the relative position of the waveform in the time record. Shift the waveform 90 degrees in the time record, and the answer on the display will change 90 degrees.

Triggering gives you control over the start of the time record. If triggering is used, then the phase of a particular signal can be stabilized. This (for example) allows the phase of harmonics to be compared to the fundamental.

If no triggering is used, the analyzer will acquire a time record when ready, which will be uncorrelated to the input signal. In this case, the phase of the signal will vary randomly from measurement to measurement.

You can also examine the relative phases between multiple signals in a single time record, as with a modulated signal.


About Trigger

89600-series analyzers let you use a trigger signal to control when the analyzer makes a measurement.

Note

For VXI measurement hardware, you connect your trigger signal to the Ext Trigger connector on the ADC module. If you have two input channels (two ADC modules), you can trigger from only one ADC module at a time—for details, see Triggering Multiple Channels.

There are several types of signals you can use to trigger the analyzer. For many of these signals, you can specify the trigger level, trigger slope, trigger delay (also called pre- or post-trigger delay), and trigger hold-off.

Trigger hold-off lets you configure the analyzer to ignore trigger signals for a specified period of time. The first trigger signal initiates a hold-off; the next trigger signal after the hold-off starts the measurement. This feature is often used in conjunction with IF Mag trigger, to trigger a measurement at the start of a pulse or burst.

The following pictures show how the trigger signal and trigger hold-off work. (Note that this is a simplified depiction of trigger hold-off. For details, see Trigger hold-off .)

Using a Trigger Signal

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Using Trigger Holdoff

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When Data Acquisition Begins

The analyzer takes data when it receives a valid trigger signal. For channel 1 (or channel 2) trigger, IF Mag 1 (or IF Mag 2) trigger, and external trigger, a valid trigger signal occurs when the trigger signal crosses the level set by level and matches the slope set by slope.

If the trigger delay is zero, the analyzer takes data immediately after it receives a valid trigger signal. If the trigger delay is positive (called post-trigger delay) or negative (called pre-trigger delay), the amount of delay determines when data acquisition begins.

For post-trigger delay, the analyzer takes data after it receives a valid trigger signal AND after the specified amount of delay has elapsed. In other words, the analyzer receives a valid trigger signal, then waits until the specified amount of delay has elapsed.

For pre-trigger delay, the analyzer takes data at some point in time before the trigger signal. The analyzer uses its sample memory to accomplish this.

You can enter delay in seconds, milliseconds, or microseconds. For pre-trigger delay, enter a negative value (as in -10 ms). For post-trigger delay, enter a positive value (as in 10 ms).

Note

If triggering is not behaving as expected, see Trigger Level and Delay Issues.


Triggering Multiple Channels

If you have a 2-channel Agilent 89610, you can trigger the analyzer from either ADC module. You must have one set of Sync connectors and one set of Clock connectors connected between the two ADC module front panels. For external triggering, you must connect the trigger signal to the channel listed above the Trigger tab in the Input dialog box.

The hardware in the ADC module samples the trigger source once every sample clock, so the trigger condition must be present for at least one sample clock in order to be recognized.

See also

About Input Channels

Two Channel Measurements

E1438 ADC Module


Trigger Tab

Menu Path: Input > Trigger

The Trigger tab lets you set up a trigger signal. For two-channel measurements, you cannot set up triggering parameters independently for each channel. Any changes you make for one channel are reflected in the setup for the other channel. Note that only one channel can be used to trigger the measurement, as indicated by the Channel check box (explained below).

•	Channel: For two-channel measurements, this check box determines if the trigger signal is from this channel. Selecting this check box automatically clears the same check box for the other input channel.

•	Type: Determines the type of trigger signal used.

•	Level and IF Level: Sets the trigger level for Channel or IF Mag trigger signals.

•	Slope: Sets the trigger slope for Channel, IF Mag, or External trigger signals.

•	Hold-off: Determines the amount of time used for trigger hold-off.

•	Display Ref Line: Determines whether the trigger reference line is displayed.

•	Delay: Determines the amount of time used for trigger delay.

For more information on triggering with non-VXI measurement hardware, see Set up Other Measurement Hardware for a link to your specific hardware.

See also

About Trigger


Delay (Trigger)

Menu Path: Input > Trigger

You can set the trigger delay for these types of trigger signals:

•	Channel (see Trigger Types for a description of Channel Trigger)

•	IF Mag, Channel Mag, or Magnitude

•	External

If delay is zero, the analyzer takes data immediately after it receives a valid trigger signal. If delay is positive (called post-trigger delay) or negative (called pre-trigger delay), the amount of delay determines when data acquisition begins.

For 2-channel analyzers, you cannot specify different trigger delay for the two channels. When you set trigger delay for one channel, the analyzer sets the delay for the other channel to the same value.

For information on trigger delay with non-VXI measurement hardware, see Set up Other Measurement Hardware for a link to your specific hardware.

Pre-Trigger Delay

Pre-trigger delay is accomplished using sample memory (RAM) in the VXI hardware. When a pre-trigger delay is selected, the analyzer stores data in sample memory until it receives a valid trigger signal. The analyzer then uses some or all of the previously collected data to achieve the pre-trigger delay.

Pre-trigger delay is limited by the amount of sample memory available for the measurement and the frequency span. Spans above 10 MHz use 12 bits per sample; spans below 10 MHz use 24 bits per sample.

Post-Trigger Delay

Post-trigger delay is limited by the range of a counter that can count up to 1G (1,073,741,824) samples. This parameter is not affected by sample memory. Again, the time represented by this count depends on the time each sample represents, which varies with span.

Note

If triggering is not behaving as expected, see Trigger Level and Delay Issues.


Display Ref Line (Trigger)

Menu Path: Input > Trigger

For magnitude or channel trigger types, you can choose to display the trigger level as a dotted line in the active trace for time data.

Select the Display Ref Line check box to display the level; clear the box if you don't want the level displayed.

For magnitude triggering, the reference line will be displayed only if the trace format is Log Mag or Linear Mag.

For channel triggering, the reference will be displayed only if the trace format is Log Mag, Linear Mag, or Real.


Hold-off (Trigger)

Menu Path: Input > Trigger

Trigger Hold-off lets you configure the analyzer to ignore trigger signals for a specified period of time.

Trigger hold-off behaves differently in the following three situations:

•	Hold-off with VXI hardware

•	Hold-off with IF Mag Trigger

•	Hold-off when you are playing back a recording

You can specify a trigger hold-off for these types of trigger signals: IF Mag, Channel Mag, or Magnitude.

You can enter the trigger hold-off in seconds, milliseconds, microseconds, or nanoseconds. You cannot specify a negative hold-off.


Trigger Hold-off with IF Mag Trigger

Trigger hold-off is designed for IF Mag triggering. When using IF Mag triggering, a potential trigger signal may occur not only at the beginning of an IF burst, but also one or more times during the IF burst. In this case, you can use trigger hold-off to ignore all trigger signals during the IF burst. Without trigger hold-off, the analyzer could start a new measurement for each trigger signal in the IF burst.

When using trigger hold-off, make sure you set the hold-off delay appropriately. For burst signals, you must use a hold-off time length that is longer than the duration of the burst, but shorter than the duration of the "quiet time" between bursts. The following example shows how to set up trigger hold-off for IF Mag triggering.

1 2 3 4 5 6 7	The start of the input signal The signal first crosses the trigger level (at approximately 0.15 mSec -- shorter than the hold-off length) Duration of IF burst - in this case approximately 0.6 mSec.  The signal drops below the trigger level for the last time in the burst, restarting the hold-off period. Duration of "quiet" time between IF bursts -- in this case approximately 1.7 mSec Hold-off period complete (assuming 1 mSec hold-off) The signal goes above the trigger level for the first time after hold-off. This will trigger a measurement.
For this example, the trigger parameters are set as follows:

−	 trigger level = 100 mV

−	 trigger slope = positive

−	 hold-off = 1 mSec (a valid setting between 0.6 and 1.7 mSec)

Assuming that the input signal repeats, each new burst will trigger one measurement.


Trigger Hold-off with Recording Playback

Trigger hold-off has the following minor differences when you are playing back a recording:

•	You can use hold-off for I+jQ measurements in playback mode.

•	Hold-off is available for all trigger types except FreeRun.

•	The input data for playback has been digitally filtered, eliminating much of the high-frequency noise.


Hold-off with VXI Measurement Hardware
Trigger Hold-off with VXI Measurement Hardware

The following information applies for using trigger hold-off with 89600 VXI measurement hardware. For information on trigger hold-off with non-VXI measurement hardware, see Set up Other Measurement Hardware for a link to your specific hardware.

Trigger hold-off specifies an amount of time that the analyzer's input signal must be a stable low value before the analyzer will accept a trigger signal. You can specify a trigger hold-off for these types of trigger signals: IF Mag, Channel Mag, or Magnitude.

You can enter the trigger hold-off in seconds, milliseconds, microseconds, or nanoseconds. You cannot specify a negative hold-off.

Trigger hold-off specifies a length of time during which the signal must be low (below the trigger level) before the trigger circuit recognizes the signal as being low. The trigger hold-off circuitry includes a magnitude comparator. The comparator output goes low only after the input signal has been low for the length of time specified by hold-off. After the signal has been low for a complete hold-off period, the next trigger signal starts the measurement.

Trigger hold-off with positive trigger slope (for E1438 and E1439 ADC modules)

For E1438 and E1439 ADC modules, if the trigger slope is positive, the trigger occurs the next time that the signal goes high (rises above the trigger level).

The following illustration demonstrates how trigger hold-off works. The top line is the input signal. It could also represent the signal envelope. The hold-off time is shown below the signal. The bottom line is the output of the comparator. The arrows labeled A through D indicate the length of the positive pulse. The measurement is triggered on edges of the comparator output.

1.	Time A is less than the hold-off time. The analyzer does not recognize the signal as being low.

2.	Time B is longer than the hold-off time. At the end of the hold-off after the signal went low, the comparator output goes low.

3.	For a positive trigger slope, the trigger occurs the next time the signal (and the comparator output) goes high.

4.	When the trigger input signal goes low again, the hold-off starts. Time C is less than the hold-off time. The analyzer does not recognize the signal as being low.

5.	Time D is longer than the hold-off time, so the analyzer will trigger when the input next goes high.

Trigger hold-off with negative trigger slope (for E1438 and E1439 ADC modules)

If trigger slope is negative, the trigger could occur immediately at the end of the hold-off period, when the comparator output goes low. For convenience, the analyzer adjusts the trigger back to the start of the hold-off period so that the trigger appears to happen at the point where the signal envelope crossed the magnitude threshold--at the end of the burst. (This is the equivalent of setting a pre-trigger delay equal to the hold-off time.)

The following illustration demonstrates how trigger hold-off works with a negative slope. The top line is the input signal. The hold-off time is shown below the signal. The bottom line is the output of the comparator. The arrows labeled A through D indicate the length of the negative pulse. The measurement is triggered on edges of the comparator output.

1.	Time A is less than the hold-off time. The analyzer does not recognize the signal as being low.

2.	Time B is longer than the hold-off time. At a time equal to hold-off after the signal went low, the comparator output goes low. For a negative trigger slope, the trigger occurs at the beginning of the hold-off, at the point where the burst signal last dropped below the trigger level.

3.	When the trigger input signal goes low again, the hold-off starts. Time C is less than the hold-off time. The analyzer does not recognize the signal as being low.

4.	Time D is longer than the hold-off time. At a time equal to hold-off after the signal went low, the analyzer accepts the signal as low. For a negative trigger slope, another trigger occurs at the beginning of the hold-off time.


Level and IF Level (Trigger)

Menu Path: Input > Trigger

You can set the trigger level for these types of trigger signals:

•	Channel (see Trigger Types for a description of Channel Trigger)

•	IF Mag, Channel Mag, or Magnitude

The trigger level that you can enter depends on the type of trigger selected, as follows:

Trigger  Type	Level  Parameter	Trigger Level  Limits	Default
Channel	Level	± percentage of range	0 V
IF Mag, Channel Mag, and Magnitude	IF Level	0.0 to + percentage of range	0.01 V
For information on trigger level with non-VXI measurement hardware, see Set up Other Measurement Hardware for a link to your specific hardware.

Tip

For the trigger types in the preceding table, the upper limit, and lower limit for Channel trigger, are a percentage of the input range and depends on the Input module and ADC module being used. To determine the limit, set the range to a value that you know will exceed the limit. In this case, the analyzer automatically sets the range to its limit.

The analyzer remembers the values that you set for each trigger type . For example, you may set level to 10 mV for the IF Mag trigger and 2 V for Channel trigger. In this example, if the trigger type is IF Mag, the analyzer uses 10 mV as the trigger level. If you change the trigger type to Channel trigger, the analyzer uses 2 V as the trigger level.

If you select the Display Ref Line check box, the trigger level appears as a dotted line in the trace display for time data.

Note

If triggering is not behaving as expected, see Trigger Level and Delay Issues.


Slope (Trigger)

Menu Path: Input > Trigger

You can set the trigger slope for the following types of trigger signals. You can specify a rising (positive) or falling (negative) slope.

•	External

•	Channel (see Trigger Types for a description of Channel Trigger)

•	IF Mag, Channel Mag, or Magnitude

For information on trigger slope with non-VXI measurement hardware, see Set up Other Measurement Hardware for a link to your specific hardware.


Trigger Types

Menu Path: Input > Trigger > Type box

The types of signals that you can use for a trigger signal are listed below. The application determines which trigger signals you can use, as shown in the tables that follow the trigger descriptions.

Note

If a particular trigger type is not available in the list for your analyzer, it is because your hardware does not support that trigger type. Unavailable trigger types are greyed in the menu, and you cannot select them.

•	Free run, which selects free-run triggering. This means that the analyzer will process time records (input data) as quickly as possible, without waiting for any kind of triggering signal. (Some analyzers call this continuous triggering.)

•	Channel, which selects the specified input channel as the trigger signal. Channel trigger is unavailable when using the 89640 analyzer with the 36 MHz-2.7GHz frequency band.

•	IF Mag, Magnitude, or Channel Mag, which select the specified channel's IF signal as the trigger signal. Only one of these trigger types is available at any time, depending on analyzer configuration. For details , see the information below and see online help for IF Mag (Trigger), Magnitude (Trigger), and Channel Mag (Trigger).

•	External, which selects external triggering. This means the analyzer begins a measurement when the external-trigger signal meets the trigger conditions you've specified. For details about external triggering, see External (Trigger).

•	External TTL, which selects external TTL triggering.

Trigger  Types	Spectrum  Analyzer Application	Vector Signal  Analyzer Application
Free Run	Yes	Yes
Channel	Yes‡	Yes‡
IF Mag,  Magnitude, or Channel Mag	No	Yes†
External	Yes	Yes
External TTL	Yes	Yes

† Only one of these trigger types is available at a time. The one that is available
 depends on instrument configuration, as shown in the next table.

‡ Channel trigger is available only for baseband measurements (Real data only)

This trigger type:	Is available when using the Vector Signal Analyzer application with this configuration:
Channel Mag	When using a two-channel analyzer and the input channel is I+jQ (ch1+j*ch2) .
IF Mag	When the time data is zoomed (real and imaginary) .
Magnitude	When the time data is baseband (real)) and the input channel is NOT I+jQ (ch1+j*ch2).
For information on trigger types with non-VXI measurement hardware, see Set up Other Measurement Hardware for a link to your specific hardware.


Channel Mag (Trigger)

Menu Path: Input > Trigger > Type box

The Channel Mag trigger type is available for the following configuration:

•	2-channel analyzer

•	Vector Signal Analyzer application

•	 input channel is I+jQ (ch1+j*ch2)

The Channel Mag trigger only triggers when your signal is within the specified frequency span, as shown in the following block diagram:

The Channel Mag trigger is usually used with amplitude modulated (AM) or burst signals. This trigger type triggers the analyzer when the input signal is within the current span, AND the input signal is varying in amplitude, AND the trigger conditions are met. The trigger conditions you can specify are level, slope, delay, and hold-off.

Note

With Channel Mag, the magnitude of the signal must vary to trigger the analyzer. The magnitude of the signal varies when the input signal switches on and off or if the input signal is AM modulated.

Trigger hold-off is often used with Channel Mag. If you are using a burst to trigger the analyzer and the burst contains more than one valid trigger edge, you can use trigger hold-off to ignore all but the first trigger edge.


External (Trigger)

Menu Path: Input > Trigger > Type box

The External trigger signal lets you trigger the analyzer using a signal connected to the Ext Trigger connector on the ADC module. The analyzer begins a measurement when the external-trigger signal meets the trigger conditions you've specified, which are slope and delay.

In a 2-channel analyzer, you must connect the external trigger signal to the ADC module specified for the channel listed in the box above the Trigger tab. For example, if the box lists Channel 1, you must connect the external trigger signal to ADC 1.

For information on external trigger with non-VXI measurement hardware, see Set up Other Measurement Hardware for a link to your specific hardware.

Special Considerations for External Triggering with VXI Measurement Hardware

Note that you cannot specify a trigger level or hold-off for external trigger.

The "Ext Trigger" connector on the ADC module is AC coupled with an impedance of 1 K ohm so any signal with a sharp rising or falling transition greater than 100 mV (i.e. TTL or ECL) can be used as an external trigger source. Minimum pulse width is 300 ns.

The hardware samples the trigger source once every sample clock, so the trigger condition must be present for at least one sample clock in order to be recognized.

•	Because External Trigger is sensitive to 100 mV changes, noise on the signal can cause false triggering. This can happen for large amplitude trigger signals, such as TTL levels, where the noise varies more than 100 mV. If your trigger signal is noisy and causes false triggering, you should either filter or attenuate the trigger signal to reduce the noise amplitude.

You can construct an adapter to terminate the cable and attenuate and filter the signal to avoid false triggering caused by noise. Package the following resistor and capacitor network in a BNC barrel. Connect the adapter to the Ext Trig input on the E1438 and the trigger cable to the adapter.

•	Because the "Ext Trigger" input is an AC-coupled comparator, External Triggering works best for high frequency signals with sharp edges (for example, sine waves do not work well at low frequencies). At low frequencies, larger amplitude trigger signals may be necessary to achieve reliable triggering.

•	Because the "Ext Trigger" input is an AC-coupled comparator with hysteresis, its initial state is unknown (the hardware doesn't know if the initial signal level represents a high state or a low state). Before using External trigger, you should apply a trigger pulse to initialize the Ext Trigger input to a known state (see following illustration).

In this example, the analyzer is set to trigger on a rising pulse and the hardware powered up assuming the incoming signal begins with a low state. The incoming signal does begin with a low state, so triggering begins with the first pulse:
This example is identical to the one above, except the hardware powered up assuming the incoming signal begins with a high state. In this case, the incoming signal actually begins with a low state, so the 1st pulse redefines the high state and low states. Triggering does not occur until the second pulse:


External TTL
External TTL (Trigger)

Menu Path: Input > Trigger > Type box

(Available only for Agilent E1439B and E1438B VXI modules)

The External TTL trigger signal lets you trigger the analyzer using a signal connected to the Ext Trigger connector on the ADC module. The analyzer begins a measurement when the external-trigger signal meets the trigger conditions you've specified: trigger level, trigger slope, and trigger delay.

 The limits are −5 Vpk to +5 Vpk.


IF Mag (Trigger)

Menu Path: Input > Trigger > Type box

The IF Mag trigger type is available when using the Vector Signal Analyzer application with zoomed (real and imaginary) time data. The IF Mag trigger only triggers when your signal is within the specified frequency span, as shown in the following block diagram:

The IF Mag trigger is usually used with amplitude modulated (AM) or burst signals. This trigger type triggers the analyzer when the input signal is within the current span, AND the input signal is varying in amplitude, AND the trigger conditions are met. The trigger conditions you can specify are level, slope, delay, and hold-off.

Note

With IF Mag, the magnitude of the IF signal must vary to trigger the analyzer. The magnitude of the IF signal varies when the input signal switches on and off or if the input signal is AM modulated.

Trigger hold-off is often used with IF Mag. If you are using an IF burst to trigger the analyzer and the IF burst contains more than one valid trigger edge, you can use trigger hold-off to ignore all but the first trigger edge.

Viewing the IF Signal

The following steps show you how to view the IF Mag trigger signal, useful for determining the best values for trigger level and slope.

1.	Make sure Digital Demodulation and Analog Demodulation are off.

2.	Click MeasSetup, Frequency:

a.	In the Time Data box, select Zoom.

b.	In the Center box, set the center frequency to the frequency of your carrier.

3.	Click Trace, Format. In the Format box, select Lin Mag.

4.	Click Trace, Data, and select a time domain display (main time).

Note

There are some considerations you should be aware of when viewing IF Mag in the time domain--see below for details.

Considerations

•	With IF Mag, the magnitude of the IF signal must vary to trigger the analyzer. The magnitude of the IF signal varies when the input signal switches on and off or if the input signal is AM modulated.

•	Trigger conditions (level, slope, delay, and hold-off) must be met to trigger the analyzer.

•	Use trigger hold-off if there are multiple, valid trigger signals within your IF signal. With trigger hold-off, you can configure the analyzer to ignore extra trigger signals.

•	To get an accurate time-domain display of the IF Mag trigger signal, make sure your input signal is within the specified frequency span.

•	If the DC level is too high, the DC level introduces a second waveform that makes the IF Mag trigger signal look like a mixed signal. This problem is most apparent with DC coupling, but may also be apparent with AC coupling.

•	To avoid problems caused by DC level, set the stop frequency high enough that DC is out of band. Usually, setting the stop frequency to 0.1 × span is sufficient; however, you may need to set it as high as 0.3 × span.


Magnitude (Trigger)

Menu Path: Input > Trigger > Type box

The Magnitude trigger type is available when using the Vector Signal Analyzer application with baseband time data (real data only). The Magnitude trigger only triggers when your signal is within the specified frequency span, as shown in the following block diagram:

The Magnitude trigger is usually used with amplitude modulated (AM) or burst signals. This trigger type triggers the analyzer when the input signal is within the current span, AND the input signal is varying in amplitude, AND the trigger conditions are met. The trigger conditions you can specify are level, slope, delay, and hold-off.

Note

With Magnitude trigger, the magnitude of the signal must vary to trigger the analyzer. The magnitude of the signal varies when the input signal switches on and off or if the input signal is AM modulated.

Trigger hold-off is often used with Magnitude trigger. If you are using a burst to trigger the analyzer and the burst contains more than one valid trigger edge, you can use trigger hold-off to ignore all but the first trigger edge.


X Scale Tab

Menu Path: Trace > X Scale

The X Scale dialog box lets you alter the X-axis scaling and positioning of data displayed in the active trace.

Note

X-axis units are determined by the trace format. For digital demodulation, X-axis units are in symbols.

•	Full Scale

•	Left Reference

•	Right Reference

•	Show Frequency Center/Span on all traces

•	Copy X Scale to

Tip

To quickly reset the x-axis to full scale: Right click in the x-axis annotation area of the display and click X Full Scale.

See also

Format tab

Digital Demod tab

Y Scale tab

Spectrogram


Copy X Scale to

Menu Path: Trace > X Scale

Copy X Scale to lets you set the X-axis scale on other traces to match the active trace.

Tip

To quickly reset the x-axis to full scale: Right click in the x-axis annotation area of the display and click X Full Scale.


Full Scale (X-axis)

Menu Path: Trace > X Scale

The Full Scale check box determines how much of the trace is displayed. When the box is selected, the full frequency span is displayed. When the box is cleared, Left Reference and Right Reference determine which part of the trace is displayed.

The Full Scale check box gets cleared when you change the X-axis scale. You can change the scale by making other selections on the X-scale tab or by using the Select Area tool and clicking either Scale X or Scale X & Y. The Full Scale check box also gets cleared when you recall data that is not full scale.

Tip

To quickly reset the x-axis to full scale: Right click in the x-axis annotation area of the display and click X Full Scale.


Left Reference

Menu Path: Trace > X Scale

Left Reference sets the value for the first point displayed. This setting is effective only when the Full Scale check box is cleared.

If you use the mouse wheel or the keyboard arrow keys to change the value of Left Reference, the Right Reference also changes to maintain the scale. The arrow keys and the mouse wheel step the value by 1/10 the scale.

If you click on Left Reference and type in a new value, the value of Right Reference does not change, but the scale changes.


Right Reference

Menu Path: Trace > X Scale

Right Reference sets the value for the last point displayed. This setting is effective only when the Full Scale check box is cleared.

If you use the mouse wheel or the keyboard arrow keys to change the value of Right Reference, the Left Reference also changes to maintain the scale. The arrow keys and the mouse wheel step the value by 1/10 the scale.

If you click on Right Reference and type in a new value, the value of Left Reference does not change, but the scale changes.


Show Frequency Center/Span on all traces

Menu Path: Trace > X Scale

Show Frequency Center/Span on all traces determines whether center/span frequency or start/stop frequency is displayed below each trace. When the check box is selected, center and span are displayed; when the box is cleared, start and stop are displayed. The default is center/span.

Selecting or clearing this check box also changes the setting of Show Center/Span in the Frequency dialog box.


Y Scale Tab

Menu Path: Trace > Y Scale

Y Scale displays a dialog box that lets you alter the Y-axis scaling and positioning of data displayed in the active trace.

•	Y Unit selects units for the y axis.

•	Reference Level vertically shifts the trace.

•	Reference Position changes the position on the display of the reference line.

•	Y Per Division compresses and expands the trace.

•	Range Tracking links the value of Y Reference Level to changes in the input range.

•	Reference Line hides or displays the y-axis reference line.

•	Vector X Center

•	Copy Y Scale to lets you set the Y-axis scale for other traces to match the active trace.

See also

Format tab

Digital Demod tab

X -Scale tab

Spectrogram


Auto Scale

Menu Path: Trace > Y Scale

Clicking Autoscale rescales and repositions the active trace to ensure that all points fall within the bounds of the trace display on the Y axis.

Autoscaling changes the values of Reference Level and Y Per Division. The new values are used until you do one of the following:

•	Enter a new value for either parameter.

•	Click Auto Scale again.

•	Toggle Range Tracking from off to on.

•	Change the input range while Range Tracking is on.

The last two cases do not apply when the data format is phase or group delay.


Range Tracking

Menu Path: Trace > Y Scale

When the check box is selected, Range Tracking is on for the active trace. When the box is cleared, Range Tracking is off.

When range tracking is on, the value of Reference Level is linked to the input range. Each time the range changes, Reference Level changes by the same amount.

Range tracking is turned off during an autoscale procedure or when you change the Y Per Division for real, imaginary, or linear magnitude data formats.

Range tracking is not available for these types of measurement data:

•	Math functions

•	Data registers (includes recalled traces)

•	Frequency response

•	Coherence

•	AM/FM/PM demodulation

Range tracking is not available for these data formats:

•	Phase

•	Group Delay


Reference Level

Menu Path: Trace > Y Scale

Reference Level sets the y-axis value of the Reference Line for the active trace.

Hint

The Reference Line lets you define an easy point of reference on the display. You can use this feature to, among other things, quickly compare multiple traces.

Overview

You can move a trace up or down by changing the Reference Level, or by changing the position of the Reference Line.

Hint

To change the size of the trace, use Y Per Division.

Using Reference Position to Move A Trace

The Reference Line is a horizontal line that is located in a fixed position on the display. The trace is referenced to this line. Moving the y-axis Reference Line up or down moves the trace up or down.

To move the Reference Line, change the Reference Position. You enter the Reference Position as a percentage of the height of the trace display. A value of 0% places the Reference Line at the bottom of the trace box; 50% places it in the center; 100% places it at the top.

Because the trace is referenced to the Reference Line, moving the Reference Line down half a screen moves the trace down by half a screen.

Note

The reference line is displayed only if the check box is selected.

Using Reference Level to Move A Trace

You can also move the trace by changing the Reference Level.

Because the trace is referenced to the Reference Line, increasing Reference Level pushes the trace down. Likewise, decreasing Reference Level pulls the trace up.

Hint

Auto Scale works by changing the value of Reference Level.

Examples

The following illustrations show how the analyzer uses Reference Level and Reference Position to position a trace.

Hint

You may want to turn on Reference Line, and vary Reference Level and Reference Position to better understand how these parameters work.

Interaction With Other Parameters

You can force the value of Reference Level to track input range changes if the data format is linear magnitude or log magnitude, and the units are compatible. To do this, select the Range Tracking check box.

The unit you use to specify the Reference Level is also used as the display unit for marker values.

Reference Level and Polar Displays

You can also use Reference Level with polar (IQ) displays. For polar displays, Reference Level, Reference Position, and Reference Line work as described above--they all help you position the polar display along the y-axis.

For polar displays, you can also specify the center value for the X axis. See Vector X Center.


Reference Line

Menu Path: Trace > Y Scale

When the Reference Line check box is selected, the analyzer displays the reference line for the active trace. When the box is cleared, the reference line is not displayed.

For further details, see Reference Level.


Reference Position

Menu Path: Trace > Y Scale

Reference Position determines the position of the Reference Line for the active trace.

−	Range: 0% to 100%

−	Step Size: 1% increments

−	Start-up/Preset State: 100%

Hint

To display the Reference Line, select the Reference Line check box.

For more details, see Reference Level.


Vector X Center

Menu Path: Trace > Y Scale

The value for Vector X Center sets the X-axis center for Digital Demodulation polar displays. The default value is zero. A negative value moves the polar display to the right; a positive value moves it to the left.

Note

This parameter is available only for vector and constellation diagrams when using Digital Demodulation.


Y Per Division or Y Ratio

Menu Path: Trace > Y Scale

The name of this parameter changes between Y Per Division and Y Ratio, depending on the Y-axis format. For LogMag (lin), the parameter is Y Ratio. For all other formats, the parameter is Y Per division.

Y Per Division defines the spacing between vertical divisions (denoted by graticule lines when Show Grid Lines is on). Increase Y Per Division to reduce the size of the trace (and the resolution); decrease it to increase the size of the trace (and the resolution).

You can also change the Y Per Division by clicking that hotspot in the display.

Y Ratio is the ratio of Y Top to Y Bottom. For example, if you display CCDF with Y Top of 100% and Y Bottom of 100 μ%, the Y Ratio is 1,000,000.


Y Unit

Menu Path: Trace > Y Scale

The y-axis units that you can select depend on two things: the measurement calculation and the format used to display the data. Trace Data determines the measurement calculation; Trace Format determines the format the analyzer uses to display the data.

Note

Power units are valid only with these trace formats: Log Mag (dB), Linear Mag, and Log Mag (lin).

For some combinations of Trace Data and Trace Format, you cannot select y-axis units (the y-axis is unitless). For other combinations, you may be able to select only one unit. And, for other combinations, you may be able to choose from several units.

You are probably familiar with most y-axis units. However, you may not be familiar with these units used for Power Spectral Density (PSD) measurements:

•	dBm/Hz (default units for PSD)

•	Vpk/rtHz

•	Vpk2/Hz

Vpk/rtHz displays the trace in volts divided by the square root of equivalent filter bandwidth (this is the square root of the power spectral density). Other choices available to you may be Vrms/rtHz, dBVrms/rtHz, or dBVpk/rtHz.

Vpk^2/Hz displays the trace in volts squared divided by the equivalent filter bandwidth. This provides power normalized to a 1 Hz bandwidth, or power spectral density (PSD). Other choices available to you may be Vrms^2/Hz.

Another Y-axis unit you may find confusing is "mrms" (milli-rms), which is the same as rms, except for dB units. The unit "dBmVrms" adds 60 dB to the dBVrms. This unit is helpful if you are looking at very small signals in dB units.


About Default Toolbars

When you perform a Preset Menu/Toolbars or Preset All, the contents of the toolbar are returned to their defaults.  The default toolbars are:

•	Control

•	Active Trace

•	Marker Tools

•	Spectrogram Tools


Active Trace Toolbar

The Active Trace toolbar [image] allows you to specify which trace you want to activate and how to display traces.

When you click a trace letter, that trace becomes the active trace and gets displayed. Any trace data, trace format, scale, or marker selections you make apply only to the active trace.  When you save or copy a trace, only the active trace is saved or copied.

The right side of the Active Trace toolbar is a shortcut to the Display Layout menu.  By clicking the box, you can choose whether to display one, two, or four traces.


Control Toolbar

The Control toolbar provides quick access to the main selections under the Control menu:

	Restart	Starts a new measurement or restarts one that was paused.  When you click this button, all current measurement data is discarded.
	Pause / Single	Pauses the current measurement.  A second click  then single steps (if Sweep is set to Single) or continues the measurement (if Sweep is set to Continuous).
	Record	Begins recording the current measurement, changes "Data From" setting (Input Menu, Data From) to "Recording".


Marker Tools Toolbar

The following Marker Tools are available:

	Use the Pointer Tool for selecting menu items or to edit values on the analyzer display.
	Use the Area Select tool to outline a rectangular area of any trace to mark it for closer examination.  You can use the borders of the rectangle to the following things:  - Scale the X axis and/or Y axis  - Set Center Freq and Freq Span  - Set band power markers. To reset x-axis to full scale: Right click in the blank area of the marker readouts, click X Full Scale. To reset y-axis to full scale: Right in the trace display area and click Y AutoScale.
	Use the Marker tool to place a marker at the location you point to.
	Use the Band Power tool to position and adjust band power markers. After you select the band power tool, click once within the active trace to position the center of the band power marker. Immediately, the pointer changes to a bi-directional arrow ↔. Click to expand the bandwidth of the markers. • Click and drag to shift the left, right, or center frequencies, simultaneously adjusting the span. • Shift-click and drag the left or right references to adjust the width of the band.  The unclicked reference remains fixed, and the clicked reference and center move. • Click and drag the center frequency line to move the band left or right while maintaining the same band width.
	Use the Time Gate tool to isolate a portion of a time record for further viewing and analysis. To use time gating, you identify a portion of the main time-record to be used for frequency-domain displays. For more information, see About Time Gating.

When you click in the trace, it affects whatever tool is active. Note that once you select a tool it remains active until you select another tool.


Spectrogram Toolbar

The Spectrogram toolbar provides quick access to the following selections from the Spectrogram dialog box:

	Show Spectrogram
	Enhance.  The box shows the current setting.  To change the setting, click in the box and use the keyboard arrow keys.  You cannot use the mouse wheel or enter a value from the keyboard.
	Map Color Scheme.  The box shows the current setting.  Click the box to change the map color.


About Calibration

Menu Path: Utilities > Calibration

The purpose of calibration (sometimes called "alignment") is to measure imperfections in the measurement system and compensate for the imperfections to improve measurement accuracy. Self calibration completely characterizes the current measurement hardware; it is not necessary to recalibrate if you change Input or MeasSetup parameters such as range, coupling, channel, span, or frequency band. External calibration allows you to compensate for devices added to the input of the analyzer.

Note

Calibration may be required if you change hardware in the Utilities > Hardware dialog box.

The following calibration information is discussed in this topic:

Self-calibration (Single Cal) for VXI Measurement Hardware

Self-calibration (Single Cal) for Other Measurement Hardware

External Amplitude Correction

External Frequency Correction (for external down converters)

Dialog Box and Tabs

Self-calibration (Single Cal) for VXI Measurement Hardware

Self-calibration applies to the analyzer measurement hardware and is initiated by clicking Utilities > Single Cal. During self-calibration, the input module interrupts the input signal path and inserts a signal from the on-board calibrator. This known signal passes through the signal path. The analyzer compares the output signal to the known signal and uses the difference for calibration.

Time and temperature changes can cause hardware performance to change. For best measurement accuracy, allow the temperature of the hardware to stabilize and run self calibration just before your measurement.

Tip

If you care about dc offset for VXI measurement hardware, you should perform a single cal whenever you cycle power on the VXI hardware. The calibration state might not indicate that calibration is required, but calibration performs an auto zero on the E1438 or E1439 module (required when you cycle power).

The software monitors instrument state and indicates current calibration state on the right side of the status line at the bottom of the display. Additionally, the display shows "CAL?" in the Trace Indicator whenever full accuracy is not available (because of incomplete or invalid calibration data, or because corrections are turned off).

Calibration during instrument warm-up is a good idea, even though full accuracy is not guaranteed until the hardware has warmed up. During warm-up, calibration provides an estimate of the instrument's frequency response that allows some of the measurement algorithms to work more successfully. This is especially true when demodulating some digital formats. Without even a rough calibration, demodulation may fail.

Note

If you do a calibration when a measurement is paused, the analyzer will restart the measurement (rather than continue it) when you click Control > Pause/Single or the [image] button. Any accumulated average data is discarded. This prevents a measurement from using two different sets of calibration data.

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Self-calibration (Single Cal) for Other Measurement Hardware

For calibration information about non-VXI measurement hardware, see Set up Other Measurement Hardware for a link to your specific measurement hardware.

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External Amplitude Correction

The analyzer allows you to apply user-supplied correction data files and to measurement results for these types of external devices:

•	Non-frequency translating devices such as attenuators, cables and amplifiers (RF calibration).

•	Frequency translating devices such as mixers and down converters (IF calibration)

You can also apply correction constants to each input channel independently. The constants include gain, delay (phase), and DC offset.

For more information, see About External Amplitude Calibration .

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External Frequency Correction

The External Frequency correction provides an interface for using an external down converter. You use External Frequency Calibration to enter down converter configuration data including the bandwidth, center, and intermediate frequencies.

For information on setting up and calibrating various analyzer configurations with external down converters, see the following topics:

Calibrating 89611 with External Down Converter

Calibrating an 89611 with Agilent PSA Option H70

Calibrating an 89640 with External Down Converter

Calibrating a 2-Ch 89610 with External Quadrature Down Converter

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Dialog Box and Tabs

The Calibration Properties dialog box includes these tabs:

•	General tab

•	Amplitude tab.

•	Frequency tab

•	Fixed Equalization (for Vector Signal Analyzer only)

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See also

Apply Correction Data

Calibration Error messages

Factory Calibration Files

Single Cal

Fixed Equalization

Extended Calibration


Calibration Error Messages

Calibration error messages are displayed in an error dialog box. The error messages are grouped here by probably cause. Suggested solutions follow each list.

Cable connection problems

Calibration will fail if hardware module cables are improperly connected or are defective. In this case you will usually see one of the following error messages:

•	Calibration failure. No baseband calibration signal detected on channel <n>; check cables

•	Calibration failure. No calibration signal detected; check cables

Solution

Verify the cable connections and perform calibration again. If you still get an error message, Go to the Hardware dialog and under each tab click on "Configure" and check that "Lock Reference" is true.

Frequency lock problems

•	Calibration failure. Frequency lock error; check cables

Solution

Verify the cable connections and perform calibration again. If you still get an error message, one of the hardware modules might be defective, or there may be a setup error. Go to the Diagnostics chapter of the Installation and Service Guide for instructions on isolating the problem. (Click Open the Installation and Service Guide Now below to open the online file, or refer to the printed manual.)

•	Calibration failure. Frequency lock error; <other error messages>

Solution

May be caused by either corrupt software or hardware. File-related errors are likely to be due to changes in files or directory permissions used by the software. Try restarting the software and recalibrating. If the error persists, try uninstalling and reinstalling the software. Be sure that you also reinstall the factory calibration files you received with your hardware, if any.

Hardware problems

•	Calibration failure. Calibrator PLL failed to lock

•	Calibration failure. Failed to trigger during cal, check cables

•	Calibration failure. Measurement hung

•	Calibration failure. Phase adjustment error: phase wraps > <x>

•	Calibration failure. Recording timed out

Solution

Perform another calibration. If you see the same message, refer to the Diagnostics chapter of the Installation and Service Guide for instructions on isolating the problem. (Click Open the Installation and Service Guide Now below to open the online file, or refer to the printed manual.)

 Open the Installation and Service Guide Now

See also

Error and Status Messages

Single Calibration

About Calibration


Factory Calibration Files

For some VXI hardware modules, calibration measurements are made at the factory and stored in a file named <model>_<s-n>.cal, where <model> is the model number of the hardware module and <s-n> is its serial number (for example, 89605A_US00000125.cal). These factory calibration files are delivered with the hardware (on 3.5" disks) and must be placed in the correct directory for the 89600 software to access it. (See "Installing factory calibration files" below.) This data is used in connection with calibration data that is measured when you click Single Cal. It is possible that a particular hardware setup may use multiple modules requiring factory calibration data.

If the hardware configuration requires such files, and the files are missing or corrupted, the software will warn you each time you start the Vector Signal Analyzer or the Spectrum Analyzer program, or when you change hardware configurations. You can still make measurements, but a measurement will be corrected only by the calibration data that is available and accuracy will be compromised. Displayed traces will be annotated with CAL? to warn you of this.

Installing factory calibration files

Factory calibration files are delivered on 3.5" disks with the associated hardware. You can install them during the software setup process. When you click Install Calibration Files, you are prompted for a directory where the calibration files reside. The installation program copies all calibration files it finds onto your hard drive, then asks if there are any others. You may change to a new disk or directory and copy more files if it is desirable. These files are a few tens of kilobytes each.

It is a good idea to load onto your system the calibration files for any hardware you are likely to use in the future with your 89600 software.

If you acquire hardware after installing the 89600 software, click Start > Programs > Agilent 89600 VSA > Install Calibration Files to install the new calibration data.

See also

Single Calibration

About Calibration


Single Cal

Menu Path: Utilities > Single Cal

Click Single Cal in the Utilities menu to calibrate the analyzer one time. A warning dialog box appears, estimating how long the calibration will take. Click Yes to perform the calibration or No to abort calibration.

Calibration starts as soon as you click Yes, interrupting any measurement in progress. Single Cal is disabled if the hardware configuration does not support calibration (for example, simulation mode).

Note

If you do a calibration when a measurement is paused, the analyzer will restart the measurement (rather than continue it) when you click Control > Pause/Single or click the [image] button. Any accumulated average data is discarded.

Calibration is done for all amplitude ranges and all frequencies regardless of instrument setup.

For information on calibration with non-VXI measurement hardware, see Set Up Other Measurement Hardware for a link to your specific hardware.

See also

About Calibration

Calibration files

Calibration Error Messages

User Calibration File Format


General Tab (Calibration Properties)
About General Tab (Calibration)

Menu Path: Utilities > Calibration, General tab

The General tab in the Calibration Properties dialog box lets you control the application of the self-calibration and external amplitude correction data to the trace data results and also reports the time of the last calibration.

When you start the Vector Signal Analyzer or Spectrum Analyzer application, the software uses the instrument state contained in the default setup to determine the calibration and correction settings. There are separate default setups for each application. The default setting for Apply Corrections to Data is on.

The following parameters are available on this tab:

•	Apply Corrections to Data

•	Last Calibrated: Time of last calibration.

Note

The Apply Corrections to Data check box does not control the Frequency tab corrections.

See also

About Calibration


Apply Corrections to Data (Calibration Properties)
Apply Corrections to Data (Calibration)

Menu Path: Utilities > Calibration > General tab > Apply Corrections to Data

Default: selected

The check box labeled Apply Corrections to Data enables or disables the correction of measurement data based on these things:

•	self-calibration data results (Single Cal)

•	correction data selected in the Amplitude tab of the Calibration Properties dialog box

•	application of fixed equalization

If you do not apply corrections to the data, the measurement will run faster, but at the expense of accuracy and demodulation performance. In some cases, digital demodulation may fail if the data is not corrected.

Note

The Apply Corrections to Data check box does not enable or disable the Frequency tab corrections.

When this check box is selected, corrections are applied to the time-domain data for the Vector Signal Analyzer application and to frequency domain data for the Spectrum Analyzer application.

When the check box is cleared, no corrections are applied.

After start-up or preset, Apply Corrections to Data defaults to selected.

Note

For information on Apply Corrections to Data with non-VXI measurement hardware, see Set Up Other Measurement Hardware for a link to your specific hardware.

Corrections with Recordings

If Apply Corrections to Data is selected, time-domain corrections are applied permanently to recordings as they are saved in any file format except SDF (Fast) format. This includes any calibration that was selected by the user at the time the signal was recorded. Correcting in this manner allows the user to save fully-corrected data for further processing using MATLAB or other mathematical software. When you recall and playback a recording, the current self-calibration and external corrections are not applied. The Amplitude tab and Frequency tab calibration parameters are disabled (greyed-out) during recording playback.

For recordings saved in SDF (Fast) format, the data is saved uncorrected, but correction data is saved with the time data. This correction is applied when you playback the time data. The Amplitude tab and Frequency tab calibration parameters are disabled (greyed-out) during recording playback.

Corrections with Ch1+j*Ch2 Measurement Recordings

Signals that are recorded in I+jQ mode should be played back in I+jQ mode. While they can be played back as 2 separate channels, the time corrections will not in general be consistent. 2-channel Baseband recordings, however, can be played back in I+jQ mode and time corrections will be accurate.

See also

About Calibration.


About External Amplitude Calibration

External calibration lets you adjust the calibration data for each input channel. You can adjust the calibration data's gain, phase (delay), and DC offset. You can also specify an RF or IF frequency response for which you wish to compensate.

External calibration provides the following benefits when Input > Channels is set to I + jQ:

•	You can compensate for external gain and/or delay imbalances between the two input channels.

•	You can remove DC offsets using external calibration rather than using AC coupling. (DC coupling is recommended for I + jQ inputs.)

External Amplitude Calibration and Recordings

For information about external amplitude calibration and recordings, see Apply Corrections to Data.

See also

General Calibration tab

About Calibration


Amplitude tab (Calibration Properties)
Amplitude tab (Calibration)

Menu Path: Utilities > Calibration > Amplitude

The Amplitude tab on the Calibration dialog box provides selections that let you adjust the analyzer's calibration data to compensate for external devices, such as cables or attenuators.

The following parameters are available on this tab:

•	External RF Calibration

•	External IF Calibration

•	Calibration Constants

Notes

•	External calibration is applied only when Apply Corrections to Data (in the General calibration tab) is selected.

•	The Amplitude tab calibration parameters are disabled (greyed-out) during recording playback.

•	The settings on this tab are saved when you close the analyzer and restored when you restart the analyzer.

The external calibration you specify applies only for the channel selected from the Channel list at the top of the dialog box. You can specify different external calibration for each channel in a multi-channel analyzer.

External RF Calibration and Calibration Constants are available for both Vector Signal Analyzer and Spectrum Analyzer applications. External IF Calibration is available only for the Vector Signal Analyzer application.

External Amplitude Calibration and Recordings

For information about external amplitude calibration and recordings, see Apply Corrections to Data.

See also

About External Amplitude Calibration

General Calibration tab

About Calibration


Calibration Constants

Menu Path: Utilities > Calibration > Amplitude

Amplitude calibration constants can be turned on and off as a group, separately from other corrections, by selecting or clearing the Calibration Constants check box.

The three calibration constants are DC Offset, Delay, and Gain.

Calibration Constants modify only the data, not the instrument state.

The Calibration Constants are set for each channel independently. When you set the constants, be sure that the correct channel is displayed in the Channel box above the constants.

For more information, see About External Amplitude Calibration.


DC Offset
DC Offset (Calibration constant)

Menu Path: Utilities > Calibration > Amplitude

Default: 0 V

(Vector Signal Analyzer application only)

The analyzer mathematically applies the specified DC offset to the input signal. For example, to remove a 100 mV DC offset from the input signal, specify a DC offset of −100 mV.

Note

With DC coupling, you still must adjust the input range to handle both the AC and DC components of your signal.

DC coupling is recommended when Input Channels is set to I + jQ. This feature lets you remove DC offsets so you can use DC coupling (instead of AC coupling) on signals that contain a DC offset.

The DC offset that you specify is applied only when external calibration is enabled and time data is baseband or the Input Channel is I + jQ.

Note

In I+jQ mode, changing the center frequency from 0 Hz (or from the External Center Frequency if Use External Down Converter is selected) may disable the DC offset calibration. DC offset is generally available in the widest spans.

See also

Calibration Constants


Delay
Delay (Calibration constant)

Menu Path: Utilities > Calibration > Amplitude

Default: 0 Sec

The Delay calibration constant applies only for the Vector Signal Analyzer application, not for the Spectrum Analyzer application.

External calibration Delay is relative to the trigger. You can also use trigger delay to compensate for the delay of external devices.

Adjusting an input channel's delay with trigger delay has the same effect as adjusting the channel's delay with external calibration. However, trigger delay is a coarser adjustment.

The frequency span determines the delay resolution for trigger delay. Frequency span does not affect the delay resolution for external calibration. Thus, the current frequency span may only let you set the trigger delay in nano-seconds, whereas external calibration lets you set the delay in pico-seconds.

See also

Calibration Constants


Gain
Gain (Calibration constant)

Menu Path: Utilities > Calibration > Amplitude

Default: 0 dB (1 V/V)

Using external calibration to change the gain of an input channel does not affect the trigger level. Regardless of the external calibration gain, you always set the trigger level relative to the actual signal level. For example, whether the gain is 1 or 100, a trigger level of 0.5 mV configures the analyzer to trigger when the input signal crosses 0.5 mV.

The Display Reference Line will reflect the user gain setting. (For example, if the gain is set to 2 and the trigger level is 0.5 mV, the Display Ref Line will appear at 1 mV on time traces.

See also

Amplitude tab

About Calibration

Calibration Constants


External RF Calibration

Menu Path: Utilities > Calibration > Amplitude

You can use External RF calibration to compensate for the frequency response of:

•	A filter or amplifier that you place between the signal of interest and the analyzer.

•	The preselection filter of an external down converter that you use to extend the frequency range of the analyzer.

•	Any network added to the analyzer input that does not translate frequency.

External RF calibration does not characterize the added device—you must do that—but it allows you to add your measured data to the internal frequency-dependent corrections, so that the measurement accurately represents the signal at the input of the added device.

Note

RF calibration compensates only for the magnitude of the specified frequency response, even if a complex response is given.

To use RF calibration, you must first measure the frequency response of the device for which you wish to compensate, over the entire range of frequencies for which you intend to use it, and with sufficient frequency resolution to describe the shape of the response. The measured data must be stored in a file. For details on how to generate the file, see User calibration file format. The name of the file and the directory it is stored in are unrestricted.

To enable this feature, choose the channel you wish to correct and select the RF Calibration check box. Then click on [image] next to the File field and browse to find the file you created previously. You can turn RF calibration on or off separately from other correction by using the RF Calibration check box. RF calibration can be independently enabled for each channel, and different files may be used for each channel.

When RF calibration is enabled, the software reads the file that describes the frequency response and selects the portion of the frequency response that is appropriate to the current measurement’s center frequency and span. For frequencies between those tabulated in the file, values are interpolated, and the inverse of the magnitude of this frequency response is used to construct a compensating filter. If the center frequency or span is changed, a different portion of the file data that corresponds to the new span is used.

Notes

•	RF calibration uses linear interpolation on the linear magnitude of the data in your file, in order to determine correction for frequencies lying between measured data points.

•	At least two data points must be defined in the file. You should use enough points to adequately describe the response shape without large errors.

•	To determine correction values outside the frequency range given in the file, RF calibration extends the value of the closest data point. To prevent this extension, you should have measured calibration data over the entire range of frequencies for which you intend to use RF calibration.

•	External Frequency calibration affects the frequencies used from the RF calibration file. If Use External Down Converter is selected, the measurement center frequency is constrained to be within the External Center Frequency ± ½ the External Bandwidth. The RF calibration data selected from the file will be for the measurement center frequency and span as affected by this External Frequency cal. That is, the RF calibration data is selected with respect to the input of the external down converter.

See also

Amplitude tab

About External Amplitude Calibration

About Calibration

About External Frequency Calibration


External IF Calibration

Menu Path: Utilities > Calibration > Amplitude

You can use IF calibration to compensate for:

•	The complex frequency response (magnitude and phase) of the IF stage of an external tuner that you add to the input of the analyzer (see Setting up an External Down Converter for examples).

•	An added network such as a narrow-band filter, when you need to compensate for complex frequency response.

External IF calibration does not characterize the added device—you must do that—but it allows you to add your measured data to the internal frequency-dependent corrections, so that the measurement accurately represents the signal at the input of the added device.

Note

In the case of an added tuner, you must use External IF calibration together with External Frequency Calibration to compensate for both the IF response and the frequency translation (and possible mirroring).

IF calibration is meant to compensate for the complex response of high-order filter shapes typical of a tuner IF. The correction is defined and applied at frequencies relative to the Intermediate Frequency (IF) if you are using External Frequency Calibration. If you are not, it is relative to the analyzer center frequency. Often the IF response does not change significantly as you change the tuner’s input center frequency. In this case, you can measure the device at one (input) center frequency and use the data to correct at any other input center frequency. (The 89600 remains tuned to the IF of the external tuner. You need to change only the External Center Frequency on the Frequency tab.)

To use IF calibration, you must first measure the frequency response of the device for which you wish to compensate, over the entire span of IF frequencies for which you intend to use it, and with sufficient frequency resolution to describe the shape of the response. The measured data must be stored in a file. See User calibration file format for details on how to generate the file. The name of the file and the directory it is stored in are unrestricted, but the file name must end with the ".cal" extension.

To enable this feature, choose the channel you wish to correct and select the IF Calibration check box. Then click on [image] next to the File field and browse to find the file you created previously. You can turn IF calibration on or off separately from other correction by using the check box. IF calibration can be independently enabled for each channel, and you can use different files for each channel.

When IF calibration is enabled, the analyzer reads the file that describes the frequency response and selects the portion that is appropriate to the span currently used. For frequencies between those tabulated in the file, the analyzer interpolates values and uses the inverse of the resulting response to construct a compensating filter. As the span changes, the analyzer uses a different portion of the file data that corresponds to the new span.

Notes

•	The frequencies given in the file are relative to the Intermediate Frequency (IF) if you are using External Frequency Calibration, or to the analyzer center frequency if you are not. Therefore, responses should be defined at negative as well as positive frequencies.

•	IF calibration corrects for magnitude and phase (or real and imaginary) responses.

•	If you are using External Frequency calibration together with IF calibration (Use External Down Converter is selected), you can change the center frequency and span of the measurement. (The measurement center frequency is constrained to be within the External Center Frequency ± ½ the External Bandwidth.) The IF calibration data will be properly applied. If Use External Down Converter is cleared, the response tabulated in the file at 0 Hertz will be applied at the analyzer center frequency, whatever its value. Therefore you must choose the appropriate center frequency and not change it. The span may be changed.

•	IF calibration uses cubic spline interpolation separately on the real and imaginary parts of the data to fill in between measured points.

•	At least 5 data points must be defined in the file. Practically, many more points are needed. You must have measured data at sufficiently close frequencies to adequately resolve the curvature of real and imaginary response, or the spline interpolation will yield incorrect answers. For devices with large phase change per hertz, this may require measurements at very closely-spaced frequencies.

•	You should measure the IF over a frequency span larger than the span that you wish to correct, so that you have a few points on either side of the desired span to anchor the ends of the spline fit.

•	To determine correction values outside the frequency range given in the file, IF calibration extends the value of the nearest point. In general you do not want this to occur.

•	When using IF calibration for in I + jQ mode, you must measure the I and Q paths separately and store them in two files, then use the I data file for channel 1 IF calibration and the Q data file for channel 2 IF calibration. Be careful when making this measurement because a signal 1 MHz above the tuner center frequency will produce a response at the same output frequency as a signal 1 MHz below the center frequency, but the responses will be different. One of these responses corresponds to negative frequency.

•	IF calibration behavior is not defined or guaranteed if Time Data is set to baseband.

See also

Amplitude tab

About External Amplitude Calibration

About Calibration

About External Frequency Calibration


User Calibration File Format

When RF or IF calibration is selected in External calibration, the analyzer reads an ASCII file to determine how to correct the measurement data. You typically generate this file based on measurements of an external device for which you wish to compensate. The file name must end in ".cal" but otherwise is unrestricted.

The file format consists of headers and data. The headers are shown in the example below, and are case sensitive. Most are required; optional headers are discussed below.

The Y data represents insertion gain at specified frequencies. The Y array, by default, represents the real magnitude of the frequency response. You can change the interpretation of the Y data by including one or both of the following headers after the line Trace Data:

YComplex 1

YFormat <format>

where <format> may be RI, MA, or DB.

YComplex with a value of 1 indicates that the Y array is complex. In this case there should be two numbers on each line, separated by spaces or tabs (not commas). If there is no YComplex specification, or its value is 0, then the Y array is real and consists of one number to a line.

For cases where the data is complex the YFormat is interpreted as follows:

YFormat RI (or no YFormat specification): Y data are real/imaginary pairs.

YFormat MA: each pair represents absolute magnitude and angle in degrees.

YFormat DB: each pair represents magnitude in decibels and angle in degrees.

For non-complex data, YFormat DB means each datum represents magnitude in decibels; any other format implies absolute magnitude. The frequencies are specified in one of two ways, described below. Correction factors between tabulated frequencies are derived by interpolation of the real (and possibly imaginary) equivalent. For frequencies outside the tabulated domain, the gain at the nearest frequency is used.

One way of specifying frequencies is by including a line containing only the character X , then listing frequencies (Hz) in ascending numerical order on succeeding lines. The list must have the same number of entries as the following Y data list.

Here is an excerpt from a file using this format. (In this example the Y data is interpreted as real magnitude in decibels.) You cannot cut and paste this information, but you can find a sample file at "<Install Directory>\Help\Signals\calibration1.cal".

	FileFormat UserCal-1.0 Trace Data YFormat DB X 20000000 31000000 99000000  . . . Y -20.204 -20.0018 -19.998  . . .

Note that the X list need not contain equally spaced frequencies. If the frequencies are equally spaced, a more compact specification may be used. This format is illustrated below. The number after XDelta is the frequency spacing in Hz and the number after XStart specifies the frequency corresponding to the first gain listed under Y. The XDelta value must be positive. (In this example the Y data is complex, in real/imaginary format. The YFormat line could have been omitted). You cannot cut and paste this information, but you can find sample files at "<Install Directory>\Help\Signals\calibration2.cal" and "<Install Directory>\Help\Signals\calibration3.cal". The data in file "calibration2" is in real and imaginary format. The data in file "calibration3" is in magnitude (dB) and phase (degrees) format.

	FileFormat UserCal-1.0 Trace Data YComplex 1 YFormat RI XDelta 10000000 XStart -20000000.1 Y 1.00494E0 -7.8125E-3 1.00073E0  -5.73730E-3 9.97924E-1 -1.07421E-2 1.00079E0  -1.68457E-2 9.98413E-1 -2.22778E-2 9.98718E-1 -2.65502E-2 9.98168E-1 -3.49731E-2  . . .

Data and headers are delimited by tabs or spaces. Each line must end in <LF> or <CR><LF>. Header strings other than those specified above are ignored. Lines beginning with // are ignored, allowing comments to be inserted in the file. Numbers in the X and Y lists as well as the XDelta and XStart parameters must be in the following format:

[sign] [digits] [decimal point] [.digits] [ {d | D | e | E }[sign]digits]

sign is either plus (+) or minus (−); and digits are one or more decimal digits. If no digits appear before the decimal point, at least one must appear after the decimal point. The decimal digits may be followed by an exponent, which consists of an introductory letter ( d, D, e, or E) and an optionally signed decimal integer. The decimal point should follow the Windows regional settings. In the US it is a period, in Europe it is typically a comma.

Note

Some network analyzers, such as the Agilent 8753, can save data in ASCII form. You can edit this file using an ASCII text editor such as Notepad to change it to one of the above formats.

See also

External IF Calibration

External RF Calibration

Factory Calibration files

Verifying User Calibration Files


Verifying User Calibration Files

After you have created a file for either External RF Calibration or External IF Calibration, follow these steps to verify that the user-calibration effect is correct.

1.	In the Vector Signal Analyzer application, set the span, center frequency, external center frequency, external frequency IF, mirror frequency button, and range appropriately.

2.	Click Utilities > Calibration > Amplitude.

3.	Clear the RF Calibration and IF Calibration check boxes.

4.	Click General and make sure the Apply Corrections to Data check box is selected.

5.	In the display area, click in Trace B to make it the active trace.

6.	Click Trace > Data, and select Correction.

7.	Click File > Copy Trace. Select D1 from the pull-down list and click OK.

8.	Click Utilities > Calibration Properties > Amplitude. Select the IF or RF Calibration check box.

9.	Click Utilities > Math > New.

a.	Click Trace Data > D1 > OK > / > Trace Data > Correction 1 > OK.

b.	Highlight the text in the Name text box, type MyCorrection, and click OK > Close.

10.	Click in Trace B to ensure it is the active trace.

11.	Click Trace >  Data >  Math >  MyCorrection.

The trace shown is the part of the IF or RF Calibration file that is applied to the channel. Changing the span, center frequency, mirror frequency button, or external frequency values may require repeating steps 2 through 9 to get another valid representation of the user IF or RF Calibration file. Note that the Math trace magnitudes are the inverse of the corrections applied to the channel.

 The Correction trace under Trace, Data is a composite of these corrections: analyzer analog corrections, analyzer digital corrections, External IF or RF Calibration, and External Gain. This trace updates whenever the span, center frequency, external frequencies, or range change.

See also

User Calibration File Format

External IF Calibration

External RF Calibration

Calibration Constants


About External Frequency Calibration

External frequency calibration controls the 89600 hardware setup, frequency axis displays, data mirroring, and trace blanking when your measurement hardware includes an external frequency converter. See Setting Up an 89640 with External Down Converter for an example setup using this feature.

When Use External Down Converter is selected, the 89600 analyzer hardware is set by default to the Intermediate Frequency (IF) specified on the Frequency tab. The displayed measurement center frequency is the External Center Frequency entered on the same tab. This reflects the fact that the external down converter is tuned to the External Center Frequency and produces an output at the Intermediate Frequency. Select Mirror Frequency if the down converter outputs a spectrum that is mirrored relative to the input.

You can change the measurement center frequency (see Changing Frequency Settings) within the limitations of the measurement hardware as well as the External Bandwidth specified on the Frequency tab. When you change the measurement center frequency and span, the measurement hardware is tuned within the IF range of the external down converter. The displayed center frequency is changed appropriately, even though the External Center Frequency is unchanged. This reflects the fact that you are looking at a different portion of the bandwidth made available by the external converter.

The measurement center frequency is limited to the External Center Frequency ± ½ the External Bandwidth, unless the measurement hardware limits are more restrictive. Spectrum displays are blanked outside the same limits.

If Use External Down Converter is selected, External RF corrections are relative to the input of the external converter, and External IF corrections are relative to the Intermediate Frequency.

External Frequency Calibration and Recordings

For information about external frequency calibration and recordings, see Apply Corrections to Data.


Frequency tab (Calibration Properties)
Frequency tab (Calibration)

Menu Path: Utilities > Calibration > Frequency tab

The Frequency tab on the Calibration dialog box provides the interface to enter the necessary input parameters required by the 89600 analyzer to use an external down converter. These parameters are used to communicate to the analyzer the down converters properties and measurement settings. The settings on this tab only apply to external down converters. After entering the input data, you can set the analyzer center frequency and bandwidth (span) to match those of your down converter (MeasSetup > Frequency > Frequency tab).

The following parameters are available on this tab:

•	External Bandwidth

•	External Center Frequency

•	Intermediate Frequency (IF)

•	Mirror Frequency

•	Use External Down Converter

Notes

The Frequency tab calibration parameters are disabled (greyed-out) during recording playback.

The settings on this tab are remembered when you close the analyzer and restored when you restart the analyzer.

External Frequency Calibration and Recordings

For information about external frequency calibration and recordings, see Apply Corrections to Data.

See also

Setting Up an 89611 with External Down Converter

Setting Up an 89640 with External Down Converter

I+jQ Measurement with External Down Converter


External Bandwidth

Menu Path: Utilities > Calibration > Frequency

Type the external down converter bandwidth in this text box. The 89600 maximum displayed bandwidth is set to this value when Use External Down Converter is selected.

See also

Use External Down Converter


External Center Frequency

Menu Path:  Utilities > Calibration > Frequency

Type the external down converter center frequency in this text box. The 89600 center frequency defaults to this value when Use External Down Converter is selected. (You can still change the 89600 center frequency within the frequency band defined by the external down converter center frequency ± ½ the External Bandwidth specified.)

When Use External Down Converter is selected, the displayed measurement center frequency is the External Center Frequency rather than the measurement hardware center frequency.

See also

Use External Down Converter


Intermediate Frequency (IF)

Menu Path: Utilities > Calibration > Frequency

Type the external down converter intermediate frequency (IF) in this text box. This is the frequency at which a sine wave signal would appear at the output of the external down converter if a sine wave is input at the External Center Frequency.

See also

External Center Frequency


Mirror Frequency (External Frequency Cal)

Menu Path: Utilities > Calibration > Frequency

Select this box if the IF output from your external down converter is mirrored with respect to the input. The 89600 software will remirror the signal to obtain the correct spectrum.

Note

If you are using an external down converter, use this parameter to mirror the frequency. If you are not using an external down converter, use Mirror Frequency in the Meas Setup dialog box.


Use External Down Converter

Menu Path: Utilities > Calibration > Frequency

Select this box to specify that the measurement hardware includes an external down converter. When the box is selected, all other parameters on this tab are in effect. When the box is cleared, all other parameters on this tab are ignored.


Fixed Equalization
About Fixed Equalization

(Vector Signal Analyzer application only.)

Fixed Equalization allows you to apply a fixed FIR equalization filter to the time data of any channel. You define the filter by its frequency response rather than by its impulse response. The frequency response must be stored in a data register.

Fixed equalization can be used for the following:

•	to normalize frequency response measurements

•	to compensate for channel differences in two-channel time domain measurements such as those required in the Distortion Suite application

•	in conjunction with Adaptive Equalization in digital demodulation measurements, for example to isolate channel response from transmitter and receiver response.

Fixed equalization is different from the adaptive equalization available with some digital demodulation formats. Fixed equalization:

•	is always available

•	is applied to the time data along with Time Corrections. and affects any measurement result (except raw main time)

•	is not adaptive and you must define the filter

•	can be applied either to zoomed or baseband measurements

A FIR filter is constructed from the frequency response data you store in a data register. The FIR filter is 200 taps long.

Note

Fixed equalization is available from Distortion Suite only if you have purchased and licensed 89600 VSA software.

Absolute or relative frequency mapping

If possible, the equalizer response is defined using the portion of the register data that falls within the current measurement span. For example, if the data register covers frequencies from 200 MHz to 236 MHz, and the measurement span is 6 MHz wide centered at 210 MHz, then the register data from 207 MHz to 213 MHz is used to define the equalizer response. This is an example of absolute frequency mapping.

If the same register data is used but measurement center frequency is then changed to 70 MHz, then relative frequency mapping must be used. The center frequency of the register data is mapped to the measurement center frequency, and an equivalent span of data is taken. In this example, register data from 215 MHz to 221 MHz is used as though it covered a frequency span of 67 MHz to 73 MHz.

Relative frequency mapping is used if some or all of the measurement span falls outside the data register's frequency span. It can be desirable when measuring across frequency converters, but can be surprising otherwise. Be careful to use a measurement span that is equal to or narrower than the span of the data register.

The calibration status message area can tell you at a glance whether equalization is on, and what frequency mapping is being used


Fixed Equalization tab
Fixed Equalization Tab (Calibration)

(Vector Signal Analyzer application only.)

Menu Path: Utilities > Fixed Equalization

Channel

If your measurement hardware has more than one input channel, choose the appropriate channel from the Channel list. The equalization settings on the tab apply only for the channel selected.

Fixed Equalization checkbox

Select the Fixed Equalization checkbox to enable fixed equalization. Clear the checkbox to turn off fixed equalization.

Register

Select a register in which you have saved frequency domain data. This data defines the frequency response of the equalizer. You can use a different register for each channel.

Invert checkbox

The usual effect of equalization is to divide the unequalized spectrum by the frequency response in the data register. Select the Invert checkbox to effectively multiply rather than to divide. This means that if you use a saved two channel frequency response (Channel 2 / Channel 1) to define the equalizer, then you should either apply it un-inverted to channel 2, or inverted to channel 1.  If you use the adaptive equalizer channel response to define the fixed equalizer, you usually apply it to either channel un-inverted.

Note

Fixed equalization is applied only when Apply Time Corrections to data is selected (General calibration tab).


Using Fixed Equalization

To enable fixed equalization:

1.	Choose the channel to which fixed equalization is to be applied.

2.	Choose a register in which you have previously saved frequency-domain data. This data defines the response of the equalizer FIR filter.

3.	Select the Fixed Equalization checkbox.

4.	Specify whether or not the equalization should be inverted.

For more information, see Fixed Equalization Tab.


Using Fixed Equalization for Two-channel Measurements
Fixed Equalization for Two-channel Measurements

Fixed equalization is useful for making two measurement channels appear to have identical  responses. This allows you to make stimulus-response measurements in either the frequency domain or the time domain. It is a more powerful technique than frequency-domain normalization, but must be applied with care. Here is an example of using fixed equalization for two-channel measurements:

1.	Connect a wide-band signal via a splitter to channel 1 and channel 2. The signal must have energy (on average) throughout the band of frequencies for which you wish to equalize. The best signals are white noise, chirps, or noise-like digitally modulated signals. They need not be periodic.

2.	Make an RMS-averaged measurement.

3.	View the Coherence trace. The coherence should be close to 1 across the span. Coherence usually increases with the number of averages. If it is consistently low in some portions of your span, you may need to change your signal so that it has energy in these areas.

4.	View the Frequency response trace, and save it to data register D1.

5.	In the Fixed Equalization dialog, select Channel 2, register D1, and select Fixed Equalization. (Alternatively, you could select Channel 1, register D1, select Fixed Equalization, and also select Invert.)

6.	If you now repeat the measurement, the frequency response should be flat in amplitude and phase.


Using Fixed and Adaptive Equalization Together

Often the adaptive equalizer is used in conjunction with digital demodulation to compensate for linear errors in the measurement system. You can view the frequency response of the channel for which the equalizer is compensating.  This response is the composite of all linear distortion between the modulator and the measurement hardware, not just of the channel. To see only the channel effects, you can do the following:

1.	Connect the modulator directly to the 89600 measurement system

2.	Set up the digital demodulator appropriately for your signal.

3.	Choose a trace and set it to show the Ch Frequency Response. (It is blank until you finish the next step.)

4.	Turn on the adaptive equalizer and let it run until your measurements show the best accuracy (e.g. the lowest EVM).  Make sure that you choose enough points per symbol to make the Ch Frequency Response cover at least your measurement span.

5.	Select the Ch Frequency Response trace and copy it to register D2. You may also save the trace in a file and later recall it into D2.

6.	On the Fixed Equalization dialog, select Channel 1, register D2, and check Fixed Equalization.

7.	Reset the adaptive equalizer and rerun the measurement, again allowing the equalizer to adapt. Now the Ch Frequency Response trace should remain essentially flat.

If you now move the measurement hardware to a different point in the signal path and let the equalizer adapt, then the Ch Frequency Response trace will show the response of the channel between the modulator and the new measurement point. For example if you use the above procedure at the input of an up converter, then move the measurement hardware to the output of the converter and reset the measurement center frequency appropriately, then the Ch Frequency Response will show the frequency-shifted response of the converter (after the adaptive equalizer settles).


Setting Up an 89611 with Agilent PSA Option H70
Calibrating an 89611 with Agilent PSA Option H70

Follow these steps to prepare the 89611 for use with an Agilent PSA option H70 as the down converter.

1.	Click here for hardware connection information.

2.	Click Utilities > Hardware > Down Converter > Agilent PSA Series RF Tuner (70 MHz IF) check box. Click OK.

3.	Calibrate the 89611 measurement hardware. Click Utilities > Single Cal.

Single Cal compensates only for the analyzer hardware. The PSA is not calibrated with Single Cal, but the analyzer does compensate for signal path losses through the PSA. If you want to increase the measurement amplitude accuracy, you can use the External Amplitude Calibration Constants feature to more accurately compensate for signal losses through the PSA (see step 4).

Note

You need not input the PSA External Frequency settings. The analyzer controls these parameters through the LAN or GPIB interface to the PSA.

4.	Compensate for the External Down Converter

This step is not required but can be used if you want to increase amplitude accuracy. This procedure uses the Amplitude Calibration Constants feature to more accurately compensate for signal losses through the PSA.

a.	Generate a known-level sine wave at the desired center frequency and connect it to the PSA RF input.

b.	Set a marker to peak, note the amplitude, and calculate the loss.

For example, input a sine wave with an amplitude of −10 dBm to the down converter RF input. If the marker reads −19 dBm, the loss is 9 dB.

c.	Click Utilities > Calibration > Amplitude.

d.	Click Calibration Constants.

e.	In the Gain text box, type a gain equal to the loss calculated in step b (in dB).

f.	Click Close.

g.	Set the 89611 reference level to the appropriate level.

5.	If you want to use RF or IF calibration files to compensate for the frequency response of the PSA, see External RF Calibration and External IF Calibration.

See also

External Frequency Calibration


Setting Up an 89611 with External Down converter
Calibrating an 89611 with External Down Converter

Follow these steps to prepare the 89611 for use with an external down converter.

Note

If the external down converter is the Agilent PSA see Setting up an 89611 with an Agilent PSA Option H70.

1.	Click here for hardware connection information.

2.	Click Utilities  > Hardware > Down Converter and make sure nothing is selected.

3.	Set up the frequency information for the external down converter.

a.	Click Utilities > Calibration > Frequency.

b.	Enter the External Center Frequency, Intermediate Frequency, and External Bandwidth of your down converter. For an 89611 analyzer, the intermediate frequency must be 70 MHz ± 20 MHz.

c.	If the IF spectrum from your down converter is mirrored, select Mirror Frequency.

d.	Select Use External Down Converter and click Close.

4.	Set the analyzer range to the appropriate level. The range refers to the signal level at the Ch1 input to the analyzer.

a.	For best distortion performance, connect the highest level signal that you want to measure to the down converter RF input. Adjust the analyzer range to the lowest value that still provides acceptable distortion performance.

b.	For best sensitivity at lower level signals, adjust the analyzer range to a lower value than in step a. As the range goes down, the displayed noise level will decrease to the point where the down converter noise dominates. Be careful not to range so low that you overload the hardware.

5.	Calibrate the 89611 measurement hardware, click Utilities > Single Cal.

Single Cal compensates only the analyzer ADC module. The external down converter is not calibrated with Single Cal but you can use the External Amplitude Calibration Constants feature to compensate for signal losses through the external down converter (see the External Down Converter Amplitude Compensation step following).

6.	Compensate for External Down Converter Amplitude

This step compensates for the signal losses through the external down converter.

a.	Generate a known-level sine wave at the center frequency set in step 3b. Apply this signal to the down converter RF input.

b.	Set a marker to peak, note the amplitude, and calculate the signal loss.

For example, input a sine wave with an amplitude of −10 dBm to the down converter RF input. If the marker reads −19 dBm, the signal loss is 9 dB.

c.	Click Utilities > Calibration > Amplitude.

d.	Click Calibration Constants.

e.	In the Gain text box, type a gain equal to the calculated signal loss (in dB).

f.	Click Close.

g.	Set the 89611 reference level to the appropriate level.

7.	If you want to use RF or IF calibration files to compensate for the frequency response of the external down converter, see External RF Calibration and External IF Calibration.

See also

Frequency tab


Setting Up an 89640 with External Down converter
Calibrating an 89640 with External Down Converter

Follow these steps to prepare the 89640 for use with an external down converter.

1.	Click here for hardware connection information.

2.	Set up the frequency information for the external down converter.

a.	Click Utilities > Calibration > Frequency.

b.	Enter the External Center Frequency, Intermediate Frequency (IF), and External Bandwidth of your down converter. You can use any IF frequency within the frequency bandwidth of the analyzer. For example, for the 89640 analyzer, the intermediate frequency can be between 30 MHz and 2.7 GHz.

c.	If the IF spectrum from your down converter is mirrored, select Mirror Frequency.

d.	Select Use External Down Converter and click Close.

3.	Set the analyzer input range to the appropriate level. The range refers to the signal level at the IF input to the analyzers Ch1 input.

a.	For best distortion performance, connect the highest level signal that you want to measure to the down converter RF input. Then adjust the analyzer range to the lowest value that still provides acceptable distortion performance.

b.	For best sensitivity at lower level signals, adjust the input range to a lower value than in step a. As the range goes down, the displayed noise level will decrease to the point where the down converter noise dominates. Be careful not to range so low that you overload the hardware.

4.	Set up the amplitude compensation for the external down converter.

a.	Generate a known-level sine wave at the center frequency. Apply this signal to the down converter RF input.

b.	Set a marker to peak, note the amplitude, and calculate the signal loss.

For example, input a sine wave with an amplitude of −10 dBm to the down converter RF input. If the marker reads −19 dBm, the signal loss is 9 dB.

c.	Click Utilities > Calibration > Amplitude.

d.	Click Calibration Constants.

e.	In the Gain text box, type a gain equal to the calculated signal loss (in dB).

f.	Click Close.

g.	Set the 89640 reference level to the appropriate level.

5.	If you want to use RF or IF calibration files to compensate for the frequency response of the external down converter, see External RF Calibration and External IF Calibration.

See also

Frequency tab


Setting Up a Dual Channel 89610 with External Quadrature Down converter
Calibrating a 2-Channel 89610 with External Quadrature Down Converter

The I/Q external quadrature down converter allows you make I and Q measurements on RF signals. This procedure shows you how to set up the 2-channel 89600 baseband analyzer, in I+jQ(Ch1+j*Ch2) mode with an external I/Q quadrature down converter.

This example uses the Agilent 71910 RF receiver with the 70911 IF section (which has quadrature I and Q outputs) as the external down converter.

1.	Click here for hardware setup information.

2.	Calibrate the 89610 measurement hardware, click Utilities > Single Cal.

Single Cal compensates only the analyzer hardware. The external down converter is not calibrated with Single Cal but you can use the External Amplitude Calibration Constants feature to compensate for signal losses through the external down converter (see the External Down Converter Amplitude Compensation step below).

3.	Set up the External Down Converter: Tune the external down converter frequency to the center frequency (Fc) of interest.

4.	Analyzer 2-channel setup configuration. This configuration is required to set the analyzers measurement Range, DC Offset corrections and down converter power loss corrections.

a.	Set the analyzer to 2-channel mode: click Input > Channels > 2 Channels.

b.	Set the analyzers Ch1 and Ch2 inputs to DC channel coupling:

1.	Click Input > Coupling, select Channel 1, select DC from the Coupling pull-down list.

2.	Click Input > Coupling, select Channel 2, select DC from the Coupling pull-down list.

5.	Set up the analyzer's Ch1 and Ch2 input range levels. The input range refers to the I and Q signal levels at the analyzers Ch1 and Ch2 inputs. The range levels are set independently and must be set to the same value.

You may set the range to achieve either the best distortion performance or the best sensitivity at lower level signals:

a.	For best distortion performance, connect the highest level signal that you want to measure to the down converter RF input. Adjust the analyzer channel 1 and channel 2 ranges to the lowest value that still provides acceptable distortion performance (Input > Range > Channel1 (or 2) > Range).

b.	For best sensitivity at lower level signals, adjust analyzer channel 1 and channel 2 ranges to a lower value than in the previous step. As the range goes down, the displayed noise level will decrease to the point where the down converter noise dominates. Be careful not to range so low that you overload the hardware. An "OV" overload status message shows if the range setting is to low.

6.	This step shows how to correct for the measurement setup I and Q channel DC Offset. Correction must be accomplished for both Ch1 and Ch2 analyzer inputs.

a.	Disconnect the RF input to the down converter.

b.	Set the display layout to show 4 trace displays (Quad 4) as follows:
Trace A: Ch1 Spectrum,	Trace C: Ch1 Main Time
Trace B: Ch2 Spectrum,	Trace D: Ch2 Main Time

c.	To stabilize the measurement results we will turn on Time Exponential averaging, click MeasSetup > Average select Time Exponential under the Average Type.

d.	Open the External Amplitude calibration properties dialog box, click Utilities > Calibration > Amplitude.

Note

The DC Offset calibration constants must be entered and applied separately for each channel.

e.	Enter the Ch1 DC Offset correction; Select "Channel 1", type the negative of the measured Ch1 Main Time trace data voltage in the DC Offset text box.

f.	Select the Calibration Constants check box.

g.	Enter the Ch2 DC Offset correction: select "Channel 2", type  the negative of the measured Ch2 Main Time trace data voltage in the DC Offset text box.

h.	Select the Calibration Constants check box.

i.	You should notice that both the Ch1 Main Time and Ch2 Main Time trace data voltages are almost 0 volts. Also, the 0 Hz frequency amplitudes for the Ch1 and Ch2 Spectrum trace data should be in the noise level of the measurement.

j.	Turn off Time Exponential averaging: click MeasSetup > Average, select Off under Average Type.

k.	Connect input signal the RF input to the down converter.

7.	This step shows how to correct for the down converter power loss. Correction must be accomplished for both Ch1 and Ch2 analyzer inputs.

a.	Make sure that the analyzer is set to 2-channel mode (click Input > Channels > 2 Channels) and the input coupling is set to DC coupling for both channels (click Input > Coupling, select Channel 1 (or 2) > Coupling > DC).

b.	Generate a reference sine wave whose frequency is offset from the center frequency (Fc) and amplitude level is known. The offset frequency should be near to (1/10 is typical), but not to exceed, one half the maximum measurement bandwidth minus (or plus) Fc.

Connect this signal to the down converter RF Input.

c.	Set markers to peak to read the channel 1 and channel 2 input power (right click in each trace and click [image] Peak). Calculate the channel 1 and channel 2 power loss which is equal to the marker amplitude minus the down converter RF input signal power.

For example, if the down converter RF input sine wave amplitude is −10 dBm and the marker reads −19 dBm, the power loss is 9 dB.

d.	Click Utilities > Calibration > Amplitude.

Note

The calibration constants must be entered and applied separately for each channel.

e.	Select "Channel 1", type the channel 1 calculated power loss in the Gain text box (in dB).

f.	Select the Calibration Constants check box.

g.	Select "Channel 2", enter the channel 2 calculated power loss and select the Calibration Constants check box.

h.	Click Close.

i.	Set the trace display reference level to the appropriate level.

8.	Set up the analyzer to measure and demodulate the combined I and Q signals. Set the analyzer to 2-channel I+jQ mode: click Input > Channels > I+jQ(Ch1+j*Ch2).

9.	Set up the external down converter frequency and configuration information.

a.	Click Utilities > Calibration > Frequency.

b.	Enter the External Center Frequency, Intermediate Frequency, and External Bandwidth of your down converter.
External Center Frequency: Set to match the down converter center frequency.
Intermediate Frequency: Must be set to 0 Hz.
External Bandwidth: Set to the down converter bandwidth.

c.	If the IF spectrum from your down converter is mirrored, select Mirror Frequency.

d.	Select Use External Down Converter and click Close.

Note

If you do not enable Use External Down Converter, the displayed frequency axis represents frequencies relative to the center frequency at the down converter and not the absolute center frequency.

10.	Make sure that the analyzer Center Frequency (Fc) and Span match the external down converter values. If they are not the correct values, then enter the proper values as described below.

Click MeasSetup, Frequency and type the center frequency in the Center text box and Span (or bandwidth) in the Span text box. The maximum measurement span is limited to the analyzer Full Span bandwidth even if the external down converter bandwidth is greater.

11.	If you want to use RF or IF calibration files to compensate for the frequency response of the external down converter, see External RF Calibration and External IF Calibration.

See also

I+jQ Measurement Tips

About I+jQ(Ch1+j*Ch2) Measurements

Frequency tab


About Preset

Menu Path: File > Preset

The file menu provides a submenu with a number of items that you can preset. The term "preset" means returning the analyzer to a known state. Such a known state provides a convenient starting point when you set up a new measurement. For the 89600 analyzer, preset refers to returning the analyzer to the factory default settings.

The settings are saved in the file default.set in the Program Files/Agilent/89600 VSA/Vector/Data directory for the Vector Signal Analyzer and in the Program Files/Agilent/89600 VSA/Spectrum/Data directory for the Spectrum Analyzer.

The types of preset available from the File menu are:

•	Preset Setup

•	Preset Menu/Toolbars

•	Preset Display Appearance

•	Preset State Defs

•	Preset All

Note that Preset never changes the hardware setup.

CAUTION

Do not destroy or overwrite any files in the Agilent 89600 hierarchy with the name "DEFAULT". In conjunction with information contained within the application programs, the files named DEFAULT.SET, DEFAULT.TOL, and DEFAULT.DAP contain information necessary to return the default measurement setup, default tool set (menus and toolbars), and default display appearance respectively.

Also, never use the DEFAULT filenames for your own settings, because doing so will make it more difficult to return to factory defaults. For more information about saving your own settings, see topics on saving setups, display appearance, and menus/toolbars.


Preset All

Menu Path: File > Preset

Presetting All presets everything listed in the other preset options. For a list of the parameters set by each preset function, see the following:

•	Preset Setup

•	Preset Menu/Toolbars

•	Preset Display Appearance

•	Preset State Defs

In addition to the parameters listed for each of the above functions, Preset All also sets digital demod setups, calibration (external amplitude and external frequency), and the recording temporary file name to their default settings.

Note that Preset never changes the hardware setup.

The settings are saved in and recalled from the file default.set in the Program Files/Agilent/89600 VSA/Vector/Data directory for the Vector Signal Analyzer and in the Program Files/Agilent/89600 VSA/Spectrum/Data directory for the Spectrum Analyzer.


Preset Display Appearance

Menu Path: File > Preset

Presetting the Display Appearance returns all parameters in the Display Appearance dialog box to their factory settings, and also returns the grid arrangement to 2 traces stacked.


Preset Menu/Toolbars

Menu Path: File > Preset

Presetting Menus and Toolbars returns the standard menus and toolbars to their factory settings, described under Default Menus and Default Toolbars.


Preset Setup

Menu Path: File > Preset

Clicking Preset Setup returns the entire set of parameters under the Input and MeasSetup menus, which together define a measurement setup, to their default settings.

Note

Preset Setup does not change the settings for digital demod properties for the recording temporary file name. To change these parameters to their default settings, you must choose Preset All.

Note that Preset never changes the hardware configuration.

For information on preset with non-VXI measurement hardware, see Set up Other Measurement Hardware for a link to your specific hardware.

The settings are saved in the file default.set in the Program Files/Agilent/89600 VSA/Vector/Data directory for the Vector Signal Analyzer and in the Program Files/Agilent/89600 VSA/Spectrum/Data directory for the Spectrum Analyzer. This includes the following parameters:

Parameter	Default setting
Input Channel(s)	Depends on hardware setup
Range	20 dBm
Coupling	AC
Trigger
Channel	Checked
Type	FreeRun
Slope	Positive
Level
Hold-off	0 sec
Delay	0 sec
Data From	Hardware
Demodulator	Off
Frequency
Bands	20 MHz to 2.7 GHz for 89640 0 to 39.06 MHz for 89610
Center	1 GHz for 89640  19.53125 MHz for 89610
Span	37.109375 MHz for 89640 39.0625 MHz for 89610
Start	981.4453125 MHz for 89640 0 Hz for 89610
Stop	1.0185546875 GHz for 89640 39.0625 MHz for 89610
Step	25 kHz
Signal Track	Channel 1
Time Data Zoom/Baseband	Zoom for 89640
ResBW	300 kHz for 89640
Mode	1-3-10
Couple	Auto
Window Type	Flat Top
Frequency Points	801
Time
Main Time Length	12.74 μSec
Max Overlap	99% for 89640
Gate on/off	Off
Length	12.74 μSec
Window Type	Flat Top
Ch1 Delay	0 Sec
Ch2 Delay	0 Sec
Average
Type	Off
Count	10
Repeat Average	Off
Fast Average	Off
Update Rate	10
Trace Layout	Stacked 2
Apply Corrections to Data (Calibration)	On
Spectrogram	Off
Buffer Depth	1000
Color Count	64
Enhance	50
Map Color	Color Normal
Threshold	0


Preset State Defs

Menu Path: File > Preset

The binary representations of the ideal states in a Constellation diagram are normally established by the demodulation standard your signal is intended to meet. Sometimes you may wish to alter the expected bit patterns. By clicking Preset State Defs, you return any such alterations to the states required by the standards.

For default values, see View State Definitions.


Preset User Color Map

Menu Path: File > Preset

Presetting the User Color Map sets the user color map to a pre-defined set of colors for spectrogram displays.


About Customizing Menus and Toolbars

Menus and toolbars can be made invisible, or they can contain any combination of selections that you wish to provide for end-users.  For example, you may want to set things up so that users cannot access a particular set of capabilities (e.g., the Edit menu). The menu and tool bars are fully customizable using the familiar Windows interface.  To modify the menus or toolbars, open the Menu/Toolbars dialog box by clicking Display, Menu/Toolbars (or by right clicking in the menu bar or tool bar).

When the Menu/Toolbars dialog box is open, you can edit menus and toolbars and add individual items by dragging and dropping them from a list onto a toolbar or menu. You can also remove items from existing toolbars and menus by dragging them out of the 89600 window.

Specifying which toolbars to display

From the Toolbars tab, you can specify which toolbars you want to display in the 89600 window.  If the checkbox for a toolbar is checked, the toolbar will be displayed.  If the checkbox is unchecked, the toolbar will not be displayed.

Adding a new toolbar

You cannot place individual tools directly in the toolbar.  You must either add them to an existing toolbar or first create a new toolbar.

You will find a step-by-step example, "Customizing Toolbars," in Customizing the Interface tutorial.

Adding a tool to a toolbar

1.	Click Display, Menu/Toolbars to open the Menu/Toolbars dialog box.

2.	Click the Tools tab.

3.	Click the category containing the tool you want to add.

4.	Click the tool you want to add and drag it to the toolbar.

5.	A dark vertical bar indicates the tool's position.  Locate the bar where you want to place the tool and drop the tool.

Adding a tool to a menu

1.	Click Display, Menu/Toolbars to open the Menu/Toolbars dialog box.

2.	Click the Tools tab.

3.	Open the menu you want to modify.

4.	On the Tools tab, click the category containing the tool you want to add.

5.	In the tools list, click the tool you want to add and drag it to the menu.

6.	Highlight the menu item above which you want to insert the new tool and drop.

Removing menus or menu items

You can remove entire menus or individual items from menus.

1.	Click Display, Menu/Toolbars to open the Menu/Toolbars dialog box.

2.	Open the menu.

3.	Click the item you want to remove and drag it out of the 89600 window.  If you want to remove the entire menu, click the menu title and drag it out of the 89600 window.

Note

If in customizing the menus you inadvertently remove the File menu or the entire menu bar, you can recover.  Close the analyzer application.  If you are in the Vector Signal Analyzer, delete this file:  C:/Program Files/Agilent/89600 VSA/Vector/Data/current.tol.  If you are in the Spectrum Analyzer, delete this file: C:/Program Files/Agilent/89600 VSA/Spectrum/Data/current.tol.  Restart the analyzer, and the default menu will be restored.

Moving menus and toolbars

To move toolbars, click the handle on the left, and drag the toolbar to a new location

When the Menu/Toolbars dialog box is active, click the menu title in the menu bar and drag the menu to a new location.

Saving and Recalling menu/toolbar setups

When you exit the 89600 application, the analyzer saves the current menu/toolbar state.  When you restart the analyzer, it will use the menu/toolbar state that was active when you last closed the application.

You can return the original menus and toolbars by clicking File, Preset, Preset Menu/Toolbars.

If you have customized the menus and toolbars, it is a good idea to save your changes. Then if someone does a preset or changes the menus and toolbars, you can return to your preferred setup simply by recalling the menu/toolbar state.

To save the menu/toolbar state:

1.	Click File, Save, Save Menu/Toolbars.

2.	Type a name for the file and click Save.

To recall a menu/toolbar state:

1.	Click File, Recall, Recall Menu/Toolbars.

2.	Locate the appropriate file and click Open.


Menu/Toolbars Dialog Box

Path: Display, Menu/Toolbars, or right-click on the menu bar

Clicking Display, Menu/Toolbars displays the Menu/Toolbars dialog box (you can also access this dialog box by right-clicking on the menu bar).  The Menu/Toolbars dialog box lets you set up menus and toolbars and then save the setup as a "tool set". These tool sets are stored under the name you assign. Tool sets are always available anytime you are running the application.  (Note that the tool sets are saved separately for the Vector Signal Analyzer and for the Spectrum Analyzer application.)

The Menu/Toolbars dialog box includes three tabs:

•	Toolbars, from which you can specify which menus and toolbars are displayed.

•	Tools, from which you can select items to add to toolbars and menus.

•	Options, from which you can apply some global options to the whole 89600 application.

See also

About Customizing Menus and Toolbars


Options Tab (Menu/Toolbars)

Path:  Right-click in menu or toolbar area, Options

The Options tab on the Customize dialog presents global options that you can apply to the entire application. This tab provides check boxes to choose normally sized icons or large ones, whether to show Screen Tips for the toolbars, and whether to display keyboard shortcuts in Screen Tips.

The tab also provides a selection for menu animations. By default, menu animations are disabled (None), but this can be changed to show menu items unfolding or sliding as you open the menus, or the animations can be made to occur randomly.

See also

About Customizing Menus and Toolbars

Menus/Toolbars dialog box


Toolbars Tab (Menu/Toolbars)

The Toolbars tab lists the available toolbars, with a check mark beside those that are currently active. To remove a toolbar from the display, uncheck it.

New

To add a toolbar, click New.  Type the name of the new toolbar and click OK.  You can add items from existing menus and toolbars to the new toolbar.  Click the desired option and drag it to the toolbar.

Rename

To change the name of an existing toolbar, highlight the toolbar in the list, then click Rename.  Type in the new name and click OK.  You cannot rename the standard toolbars created by the analyzer.

Delete

To delete a toolbar, highlight the toolbar in the list, then click Delete.  You cannot delete the standard toolbars created by the analyzer (but you can choose not to display these toolbars by unchecking them in the toolbar list).

See also

About Customizing Menus and Toolbars

Menus/Toolbars dialog box


Tools Tab (Menu/Toolbars)

Path:  Right-click in menu or toolbar area, Tools

The Tools tab on the Customize dialog box lists all the categories of tools that can be added to menus and toolbars. Each time you click a category from the list on the left, the available tools in that category are listed on the right.

To add a tool to the user interface, select the tool by clicking it and then drag it to the location you wish.  If you want to add a tool to an existing menu, you must open the menu before you select and drag the tool.

See also

About Customizing Menus and Toolbars

Menus/Toolbars dialog box


About Demodulation Setup

(Vector Signal Analyzer application only.)

The analyzer demodulation setup process consists of two steps:

1.	Selecting (turning on) the desired demodulator by clicking MeasSetup > Demodulator and choosing from the list.

2.	Configuring the modulator parameters. Each demodulator type has a unique set of associated properties that you access by clicking MeasSetup > Demod Properties.

See also

Selecting a Demodulator


Selecting a Demodulator

(Vector Signal Analyzer application only.)

Menu Path: MeasSetup > Demodulator

The MeasSetup > Demodulator menu lets you select a demodulator or turn off demodulation.

•	Demod Off:  Turns off (disables) the demodulation function.

•	Analog Demodulator

•	Digital Demodulator (Available only with Opt AYA)

•	3G Cellular modulations formats:

−	W-CDMA (3GPP) Modulation Analysis (Available only with Opt. B7N)

−	cdma2000 Modulation Analysis (Available only with Opt. B7N)

−	1xEV-DO Modulation Analysis  (Available only with Opt. B7N)

−	TD-SCDMA Modulation Analysis :  Adds TSM "TD-SCDMA System for Mobile" and N-TDD "ULTRA TDD - Low Chip Rate (or Narrow TDD)" vector modulation analysis. (Available only with Opt. B7N)

•	Wireless Networking modulation formats:

−	OFDM 802.11a and HIPERLAN/2 Modulation Analysis (Available only with Opt. B7R)

−	WLAN-DSSS  802.11b and 802.11g Modulation Analysis  (Available only with Opt. B7R)

Selecting the demodulator is the first step of a two-step process required to configure the analyzer to demodulate and analyze a modulated signal. You can read more information about demodulation setup in the About Demodulation Setup topic.

See also

About Demodulation Setup

Analog Demodulation Measurement Tutorials


About Analog Demodulation

Analog demodulation lets you demodulate the following analog-modulated signals.

•	Amplitude modulated (AM)

•	Frequency modulated (FM)

•	Phase modulated (PM)

Turning on Analog Demodulation

You turn on analog demodulation by selecting the analog demodulator (click MeasSetup > Demodulator > Analog Demod). You then open the demodulation properties dialog box and set the analog demodulation parameters (click MeasSetup > Demod Properties).

Overview

Analog Demodulation lets you characterize amplitude modulated, frequency modulated, and phase modulated signals in both the frequency domain and the time domain. The analyzer determines the amplitude, phase, or frequency deviation of the modulating signal relative to the carrier.

If averaging is on, the carrier amplitude obtained by averaging across the current time record is fed into an exponential average of estimates from prior time records. The resulting averaged carrier amplitude estimate is used for the above AM calculation.

PM and FM demodulation let you select automatic carrier-frequency estimation algorithms. For PM and FM demodulated traces, you can display the estimated carrier frequency using demod carrier. Averaged measurements also average the estimated carrier frequency for FM, and estimated carrier amplitude for AM.

Modulated signals commonly consist of a high frequency carrier-signal modulated by lower frequency audio, video, or data signals. These may also be contaminated with unintentional sources of modulation.

Analog Demodulation recovers the baseband-modulating signal, which is contained in the sidebands of the carrier signal. One example is a VCO turn-on transient, in which the stable oscillating frequency can be considered a carrier, and overshoot an FM or PM modulation of the carrier.

See also

Reasons to use Analog Demodulation

Analog Demodulation Block Diagram

Special Considerations for Analog Demodulation

AM Demodulation

FM Demodulation

PM Demodulation

Auto Carrier

Analog Demodulation Measurement Tutorials


Analog Demodulation Block Diagram

(Vector Signal Analyzer application only.)

The following block diagram shows how the analyzer demodulates analog signals.


Reasons to use Analog Demodulation

(Vector Signal Analyzer application only.)

AM, PM, and FM signals commonly consist of a high-frequency carrier signal modulated by a lower-frequency audio, video, or data signal. For these signals, analog demodulation removes the carrier frequency leaving the modulating signal which is contained in the sidebands of the carrier signal.

The most obvious use for analog demodulation is analyzing intentionally modulated signals as noted above. However, analog demodulation is also useful in analyzing signals which are not intentionally modulated. For example, you may choose to:

•	Apply phase and frequency demodulation to oscillator or synthesizer designs to examine phase and frequency trajectories during frequency hops or to establish phase-lock-loop lock-up time.

•	Demodulate a burst signal to evaluate wait time to determine when a signal stabilizes.

•	Amplitude and phase demodulate sidebands to determine the type of modulation present in phase noise.

•	Demodulate bearing noise in mechanical measurements to examine frequency instability.

•	Examine frequency versus time of chirp signals.


Special Considerations for Analog Demodulation

(Vector Signal Analyzer application only.)

Analog demodulation requires certain conditions and has certain constraints, as described in the following paragraphs:

•	The analyzer automatically selects zoom mode if you select analog demodulation. Analog demodulation requires zoom mode in order to identify the carrier. The center frequency should be set as close to the carrier frequency as possible. The center frequency is programmed into the digital local oscillator, and represents the initial estimate of the carrier frequency.

•	Analog demodulation requires a positive start frequency.

•	The visible demodulated span contains only half the number of points that were contained in the original signal−the complex waveform is transformed into a real waveform which cuts spectral information in half. Analog demodulation operates only on double sideband signals. Therefore, the information in one sideband is redundant and the analyzer mixes the signal down to baseband (zero Hertz start), eliminates the carrier, and eliminates the lower sideband.

•	The resulting time record displays amplitude versus time (AM demodulation), frequency versus time (FM demodulation), and phase versus time (PM demodulation).

•	Only one demodulator per channel can be selected at a time.

•	The span must be set to include the carrier and all of its sidebands. Setting a span which is too narrow will cause distortion.

•	The bandwidth of the demodulator is approximately equal to the span.

•	When using Analog Demodulation, features such as gating, band power markers, and averaging work as described for vector measurements. When demodulating, the entire time record is demodulated.


Corrections and Analog Demodulation

(Vector Signal Analyzer application only.)

Corrections compensate for magnitude and phase errors in the analyzer's input circuitry. Corrections compensate for these errors before the Analog Demodulation process. Left uncorrected, these errors introduce errors in the demodulated signal and also introduce cross modulation products such as PM-to-AM conversions.

Corrections compensate only for distortion over the selected frequency span, which is the bandwidth going into Analog Demodulation. Sidebands or other signals that fall outside of the frequency span but have not been completely attenuated by the analyzer's digital filter are subject to distortion and can create errors in the demodulation measurement. Frequencies between the ends of the frequency span [CF ± (Span/2)] and approximately [CF ± (Span × 1.50/2)] should not contain any signals.

A larger factor, 1.50, is used than the usual 1.28—a factor of 1.28 is used for computing the guard band on spectrum displays. For time displays, 1.50 is used to assure alias protection from signals above Fs/2 folding into the guard band as a result of tossing every other point in the last step of decimation.

Spectrum displays avoid showing alias errors by not showing frequencies in the guard band. However, time results are globally affected by any signals with frequencies in the guard band, or frequencies above the guard band not yet fully attenuated by the digital filters aliasing back into the guard band.


The Importance of Span Selection

(Vector Signal Analyzer application only.)

Analog demodulation is performed on the displayed span. Therefore, it is very important to select your span carefully for the best results. If your display truncates your signal's sidelobes, distortion will result as you can see in the illustrations below.

Note

The following illustrations were created with an Agilent 89400-series analyzer. You can make the same measurements with the Agilent 89600-series analyzers. The concepts demonstrated in the illustrations apply to all analog demodulation measurements.

The next illustration shows the spectrum of a phase modulated signal. Notice that the span does not include all of the sidebands.

The next illustration shows PM demodulation applied to the above signal. Because the span truncated some sidebands, the demodulated signal contains distortion.

The next illustration is the spectrum of the same phase-modulated signal, but this time the span includes all sidebands.

The next illustration shows the results of PM demodulation. There is no distortion because the span includes all sidebands.

Checking for interfering signals

Signals slightly outside the displayed span may interfere with demodulation. Because of filter roll-off, the selected span may be influenced, during demodulation, by signals within the guardband. You should check for such signals with a wider span (1.28 times the desired span) before selecting your measurement span for a demodulation measurement.

The two illustrations below illustrate the results of demodulating a signal with an interfering signal nearby. The first illustration contains what seems to be an ideal span. However, the second illustration shows that another signal (this one FM) appears in the guard band outside the desired span

The following illustration shows interference caused by demodulating the 40 kHz span above, which is affected by the signal present in the guard band.

The demodulated signal below shows the result if the interfering signal did not exist or existed outside the guard band.


Bandwidth Concepts for Analog Demodulation

(Vector Signal Analyzer application only.)

Analog Demodulation produces a baseband result (the start frequency is 0 Hz), at half the selected frequency span.

The input bandwidth to the Analog Demodulation algorithm equals the frequency span. The output bandwidth of the Analog Demodulation algorithm is half the frequency span.

The output bandwidth is half the input bandwidth because Analog Demodulation operates only on double sideband signals. With double sideband signals, the information in one sideband is redundant.

Therefore, the Analog Demodulation algorithm produces a baseband result (start frequency of 0 Hz) to eliminate the need to show the lower sideband on a spectrum display. The result is that the Demodulation algorithm produces a visible span that is half the selected frequency span and contains half as many frequency points.


Triggering With Analog Demodulation

(Vector Signal Analyzer application only.)

The analog demodulator is located after the triggering circuits, so it is not possible to trigger on the demodulated signal. However, if the signal is AM modulated or pulsed, IF trigger can be used to obtain a stationary time waveform. External triggering (or triggering on second input channel) can be used if the original modulating signal is available.

Triggering either coherently with the demodulated waveform, or directly on the demodulated waveform in the case of IF Magnitude Triggering on the envelope, can provide stable waveforms for stationary signals, or synchronization to transient events.

One key benefit to triggering on the demodulated AM, PM, or FM signal is that very high dynamic range measurements can be achieved when using time averaging on stationary modulation signals−in excess of 30 dB beyond non-triggered demodulation measurements when power-of-2 spans are used.

Triggering on a stationary demodulated signal enables use of time averaging, which is a true, time-domain average. While rms averaging shows the demodulated signal plus noise power, time averaging gradually averages to zero any time components not coherent with the demodulated signal, such as noise.

You must select Auto Carrier Frequency to use Time Averaging. For PM, you can also select Auto Carrier Phase, which is generally best.

Channel triggering is performed before digitizing the signal. Analog demodulation is performed after digitization, preventing use of Channel triggering on the demodulated signal.

Thus, two options are available for triggering on the demodulated signal:

3.	IF Magnitude Triggering You can use IF magnitude trigger to provide a stable AM waveform for carriers that are AM modulated with a periodic signal. IF magnitude trigger is a digital envelope detection and can be set to trigger on the AM envelope. Triggering on a pulsed carrier is also possible with IF magnitude trigger. Many digital communication signals have a non-constant envelope characteristic. If your signal has envelope fluctuations, you must set the trigger level below the envelope fluctuations to prevent multiple triggers during a pulse.

4.	External Triggering You can use external triggering to acquire stable AM, PM or FM demodulated waveforms for carriers that are modulated with a periodic signal. In this case, the modulating signal must be available and connected to the external trigger (or, under some measurement circumstances, to a second input channel, in which case channel triggering can be used in the same manner as external triggering). If a trigger signal is available that is synchronous to a transient event on the carrier, connecting it to the external trigger will provide demodulation synchronization.


Selecting Analog Demodulation

(Vector Signal Analyzer application only.)

Menu Path: MeasSetup > Demodulator,

MeasSetup > Demodulator > Analog Demod turns on the analog demodulator.

After selecting the analog demodulator you need to configure the analog demodulation parameters.

See also

About Analog Demodulation

Selecting a Demodulator

Analog Demod Dialog Box

Analog Demodulation Measurement Tutorials


Analog Demod Dialog Box (MeasSetup)
Analog Demod Dialog Box

(Vector Signal Analyzer application only.)

Menu Path: MeasSetup > Analog Demod

The Analog Demod dialog box lets you select the type of analog demodulation to be applied to your signal. You can select AM, PM, or FM demodulation. In addition, you can enable Auto Carrier Phase and/or Auto Carrier Frequency. Auto carrier controls how the analyzer determines your carrier frequency.

Note

You must enable Analog Demodulation before you can select AM, PM, or FM demodulation. To do this, click MeasSetup > Demodulator > Analog Demod.

See also

Analog Demodulator

Analog Demodulation Block Diagram

PM Demodulation

AM Demodulation

FM Demodulation

Auto Carrier


AM Demodulation

(Vector Signal Analyzer application only.)

Menu Path: MeasSetup > Analog Demod

The analyzer uses the following algorithm to perform AM demodulation:

As shown in the following illustration, AM demodulation averages the carrier amplitude to derive the modulation index from the envelope.

AM Demodulation and Averaging

Carrier amplitude estimates are always performed on AM calculations, as an estimate of the carrier amplitude is required to produce units of modulation depth.

For AM measurements, the carrier-amplitude estimate from the current time record is fed into an exponential average of estimates from prior time records. The resulting averaged carrier-amplitude is used as the carrier amplitude in the current time record's AM calculation.

See also

AM Demodulation Measurement Tutorial


FM Demodulation

(Vector Signal Analyzer application only.)

Menu Path: MeasSetup > Analog Demod

For FM demodulation, auto carrier frequency determines how the analyzer identifies your carrier frequency. If auto carrier frequency is off, FM is the derivative of PM. If auto carrier frequency is on, FM is still the derivative of PM, but now the phase offset differentiates to 0 and auto carrier frequency removes the frequency error,ωΔ.

Selecting auto carrier frequency performs carrier frequency estimation. The carrier frequency estimate is used to remove frequency offsets from the FM time result. If averaging is on, the carrier frequency estimate from the current time record is fed into an exponential average of estimates from prior time records. The resulting averaged carrier frequency is used to remove the frequency offset from the current FM time result.

The estimated carrier frequency can be displayed by turning on demod carrier.

Hopping carriers are best viewed without auto carrier frequency, because the estimate of carrier frequency is made as an average over each time record. See Auto Carrier Frequency with FM Demodulation for more details.

The analyzer performs FM demodulation by differentiating a PM demodulated waveform. This differentiator is very accurate (± 0.005 dB deviation from ideal) over the selected frequency span.

The following illustration is an example of a carrier FM modulated by a sine wave. The illustration shows the effects with and without auto carrier frequency.

See also

FM Demodulation Measurement Tutorial


PM Demodulation

(Vector Signal Analyzer application only.)

Menu Path: MeasSetup > Analog Demod

PM demodulation is computed as an arc tangent of the complex time record.

For PM demodulation, auto carrier frequency and auto carrier phase determine how the analyzer handles frequency and phase errors between your carrier frequency and the analyzer's LO.

Selecting auto carrier phase subtracts the mean phase across the time record, moving the mean phase to zero. No frequency estimation is performed. Thus, this type of auto carrier is useful when the analyzer is locked to an external reference which is coherent with your carrier.

Selecting auto carrier frequency performs carrier frequency estimation, as well as moving the mean phase to zero. To display the estimated carrier frequency, turn on demod carrier.

The following illustration shows how the analyzer detects the carrier phase and frequency.

The following illustration is an example of a carrier PM modulated by a sine wave.

See also

PM Demodulation Measurement Tutorial


Demod Carrier

(Vector Signal Analyzer application only.)

Menu Path: Markers > Calculation

Demod carrier displays the carrier frequency for the active trace if the trace is the result of PM or FM demodulation. Click Markers > Calculation, and the Demod Carrier checkbox to display the carrier frequency.

Note

When you save a demodulated trace, the carrier frequency is saved with the trace. After recalling the trace, it can be viewed by turning on demod carrier.

Typically, you use demod carrier with auto carrier frequency

When no carrier frequency estimates are performed, the center frequency is used in the demodulation algorithm as the carrier frequency. Hence, the center frequency is displayed instead. No carrier frequency is involved in AM, and hence, no display is given for AM results.

Averaging

When either time or rms averaging is selected, the carrier frequency for FM or carrier amplitude for AM is estimated for the current time record and fed into an exponential average. This provides an effect similar to loop bandwidth on a phase locked loop. Increasing the number of averages is equivalent to narrowing the loop bandwidth.

The current, averaged carrier estimate is used in the AM and FM algorithms.

See also

AM Demodulation

FM Demodulation


Auto Carrier

(Vector Signal Analyzer application only.)

Menu Path: MeasSetup > Analog Demod

When analog demodulation is selected, you can select two different types of auto carrier depending on the type of demodulation, as shown in the following table.

For this demodulation:	You can use this auto carrier:
AM	None
FM	Auto Carrier Frequency
PM	Auto Carrier Frequency and Auto Carrier Phase
Note

You cannot select auto carrier frequency with AM demodulation. This is because carrier amplitude estimates are always performed. AM demodulation does not require carrier frequency estimation because the AM calculation is based on the carrier envelope. The carrier amplitude estimate is based on data within a single time record and is updated on a record-by-record basis.

Auto Carrier Frequency

Accurate angle demodulation (FM or PM) depends on precisely identifying the carrier frequency. Errors result in phase ramping. The arc tangent of the complex time record is the basis of both PM and FM demodulation. Hence, correcting for the phase ramp is the goal of auto carrier frequency.

Without auto carrier frequency, the analyzer uses its center frequency to determine the carrier frequency of your signal. When auto carrier frequency is selected, the analyzer uses an algorithm to estimate the carrier frequency. If you can lock the analyzer to an external reference which is coherent with your carrier, no carrier frequency estimation is needed, and you do not need to select auto carrier frequency.

When auto carrier frequency is selected, the carrier frequency estimate is calculated independently for each time record, and is used in the demodulation calculation to take out FM offsets, or PM phase ramps due to error between your carrier frequency and the analyzer's LO (center frequency).

Hint

If auto carrier frequency is selected, you can select demod carrier to display the estimated carrier frequency for FM demodulation. Cross channel results show the estimates for both channels. For PM demodulation, you must select both Auto Carrier Frequency and Auto Carrier Phase to display the estimated carrier frequency.

Auto Carrier Frequency and Averaging

The operation of auto carrier frequency is modified if averaging is turned on. For FM measurements, the carrier frequency estimate from the current time record is fed into an exponential average of estimates from prior time records. The resulting, averaged carrier-frequency is used to compensate the current time record for carrier-frequency offsets from the center frequency.

Considerations When Using Auto Carrier Frequency

The following situations can bias the phase ramp estimation:

•	Low frequency modulation, such as a periodic signal with fewer than 10 cycles over the time record.

•	Phase discontinuities present in digital communication formats.

•	Transients, such as carrier turn-on in the middle of the time record.

In cases where biases are unavoidable, auto carrier frequency should be turned off. Where possible, lock the analyzer's external reference to a reference coherent with the carrier to eliminate frequency errors.

Auto Carrier Phase

PM demodulation also has the option of correcting for phase offsets. A phase offset does not affect FM results, because the offset differentiates to zero.

See also

FM Demodulation

PM Demodulation


Zero Span Measurements

If you are accustomed to making zero span measurements, you can use AM demodulation to make similar measurements. The information bandwidth of other analyzers is limited by the resolution bandwidth filters, but in the Agilent 89600 series analyzers the information bandwidth is limited only by span. Therefore, AM demodulated signals appear similar to zero span measurements with a wider choice of information bandwidth.


Disconnecting from Hardware
Disconnecting from Measurement Hardware

Menu Path: Control > Disconnect

You can temporarily stop all communication between the VSA software and any measurement hardware by clicking Disconnect. Communication begins again when you start or continue a measurement. The analyzer reconfigures the hardware before starting or resuming the measurement.

Note

Disconnect does not affect the source. To allow front panel control of the source, click Source, Control, and clear the Enable check box.


Pausing and Single-Stepping a Measurement

Menu Path: Control > Pause/Single
Or: Pause/Single button on the Control toolbar

If continuous sweep is selected, Pause/Single functions as a pause/continue button. Click it to pause the measurement; click it again to continue the measurement.

If single sweep is selected, Pause/Single functions as a single-sweep button. Click it to perform a single sweep. If a sweep is in progress, Pause/Single waits until the sweep is finished before beginning a new sweep.

Note

If external trigger is selected and you click Pause/Single, the analyzer waits for the external trigger signal before it performs the single sweep.

Viewing paused data

When a measurement is paused, the most recent measurement data is preserved in RAM. Because of this, you can view the "paused" data in different ways. In fact, you can still perform these operations:

•	All operations under the Display menu.

•	Any time-gating operation.

•	Most marker operations.

For example, you can select a different trace calculation (from the main menu, click Trace > Data), different coordinates (click Trace > Format), or change the scaling or units (click Trace > Yscale or Trace Xscale).

Or, you can turn on markers and perform any marker operation. For example, you can turn on the band- power markers and select band power to compute the power between the band-power markers.

Changing measurement parameters

When a measurement is paused, you should be aware of the following when changing measurement parameters (measurement parameters are located under MeasSetup on the main menu):

•	Measurement changes take effect immediately, which may make the measurement data questionable. Because of this, the analyzer displays DATA? when you change most measurement parameters.

•	Some measurement changes clear any existing data.

•	Changes to time-gating parameters are permitted--these changes take effect immediately and yield a valid answer.

Averaged measurements

The operation of Pause/Single remains the same for averaged measurements:

•	If continuous sweep is selected, pauses (or resumes) the averaged measurement.

•	If single sweep is selected:

−	performs the next average or

−	does nothing if an average is in progress.

For non-exponential averages that stop when the number of averages (N) are completed, the operation of Pause/Single differs slightly, as shown in the following table:

If the average is non-exponential, and the number of averages (N) are completed:

If repeat  averaging is:	and the  sweep is:	Clicking Pause/Single does this:
OFF	single	Adds another average to the total (N + 1).
OFF	continuous	Performs another "N" averages (includes the results from previous averages).
ON	single	Performs the 1st average of a new, averaged measurement
ON	continuous	Pauses or resumes the averaged measurement.
See also

About Averaging.

Selecting an Averaging Type


Setting up a Swept Measurement

Menu Path: Control > Sweep

The analyzer lets you control the sweeping operation of the analyzer. You can select:

•	Continuous, which performs consecutive sweeps without stopping.

•	Single, which stops after each sweep.

Continuous sweep

By default, the analyzer selects continuous sweep to perform consecutive sweeps without stopping. To initiate sweeping, click Restart. To pause and resume a sweep at any time, click Pause/Single.

Single sweep

Single sweep configures the analyzer to stop after it completes a sweep. To initiate the sweep, click Pause/Single. If you click Restart, the analyzer clears existing data and displays a message informing you to click Pause/Single to initiate the sweep. If averaging is on and single sweep is selected, clicking Pause/Single performs the next average.


Starting and Stopping a Measurement

Menu Path: Control > Restart
Or: Restart button on the Control toolbar ( [image] )

Note

Restart is available from the Control menu or as a button, [image] in the Control toolbar.

Pause/Single is available from the Control menu or as a button, [image] in the Control toolbar.

Stop is available only from the Control menu.

Clicking Restart clears existing data and starts a new measurement. Clicking Stop stops the current measurement and clears existing data.

If the analyzer is already making a measurement, clicking Restart clears all measurement data from the analyzer's buffers and starts the measurement over again. This differs from the action of Pause/Single, which does not clear the buffers.

Operation With Single Sweep

If Single sweep is selected (Control menu), then clicking Restart clears measurement data and initiates a measurement. To initiate a measurement without clearing measurement data, click Pause/Single.

Operation With External Arm & Trigger

Clicking Restart does not provide a trigger signal. If you want to select a trigger signal, click Input, Trigger. Select an appropriate trigger option from the dialog box.

Operation With Averaged Measurements

The operation of Restart remains the same for averaged measurements. If the averaged measurement is collecting averages, clicking Restart starts a new averaged measurement, beginning with the first average. Clicking Pause/Single does not reset the number of averages. If Single sweep is on during averaging, use Pause/Single to initiate a new trace and average it.


Undo

Menu Path: Edit > Undo

Click Undo to reverse the last action performed on a trace.


Copy Text

Menu Path: Edit > Copy Text

Click Copy Text to write the unscaled version of the current text box or text area to the clipboard, along with the associated base units. For example, if you right click on the Center Frequency text area of a Spectrum trace, then select Copy Text, the value "1000000000 Hz" is copied to the clipboard (assuming default setup).


Copy Trace Data

Menu Path: Edit > Copy Trace Data

Click Copy Trace Data to write the current trace data to the clipboard. Then you can paste the data into another Windows application, such as Microsoft Excel, for analysis, manipulation, or documentation.


Copy Markers

Menu Path: Edit > Copy Markers

Click Copy Markers to write the current marker readouts to the clipboard. Then you can paste the information into another Windows application, such as Microsoft Excel or Microsoft Word.

If markers are off for the active trace, Copy Markers is not available.


About Input Channels

Menu Path: Input > Channels

From the Input Channels menu you specify whether the analyzer should use 1 channel, 2 channels, or I+jQ inputs. For single channel analyzers, only 1 channel is valid.

•	Select 1 Channel to measure data from Channel 1.

•	Select 2 Channels to measure data from Channels 1 and 2.

•	Select I+jQ(Ch1+j*Ch2) to measure data from both channels, where Channel 1 data is Real and Channel 2 is Imaginary. (For Digital Demodulation measurements, selecting I+jQ(Ch1+j*Ch2) lets you input your I signal on Channel 1 and your Q signal on Channel 2.)

For two-channel measurement hardware, when you change from the input selection between one channel and either two channels or I+jQ inputs, the analyzer changes the Frequency Band and frequency settings to their preset values.

For information on input channels with non-VXI measurement hardware, see Set up Other Measurement Hardware for a link to your specific hardware.

See also

Input menu

Two-Channel Measurements

Ch1+j*Ch2 Measurements


Two Channel Measurements

Menu Path: Input > Channels > 2 Channel

Some 89600 analyzers support two input channels. The second input channel is optional and depends on your measurement hardware.

For VXI measurement hardware, a second ADC module is required, and you must specify the ADC by selecting the second module from the ADC2 list. For other measurement hardware, you specify only one ADC and activate the second channel by selecting 2 Channels or I+jQ from the Input Channels menu.

Note

The Spectrum Analyzer application does not support I+jQ(Ch1+j*Ch2) measurement.

See also

Ch1+j*Ch2 Measurements


About Ch1+j*Ch2 Measurements

Menu Path: Input > Channels > 2 Channel > I+jQ(Ch1+j*Ch2)

For analyzers with two input channels, you can click Input > Channels > I+jQ(Ch1+j*Ch2) to measure data from both channels, where Channel 1 data is Real and Channel 2 is Imaginary. Or, if you're using Digital Demodulation, Channel 1 is the "I" signal and Channel 2 is the "Q" signal.

Note

The Spectrum Analyzer application does not support I+jQ(Ch1+j*Ch2) measurement.

There are several applications for this feature.

•	You are making transmitter/receiver measurements and you want to input the I and Q components directly into the analyzer for analysis.

•	You want to make RF measurements using an external quadrature down converter connecting the I/Q outputs to a 2-channel 89610A for analysis.

•	You use an Agilent E4406 VSA with Baseband I/Q as the measurement hardware with your 87600 software.

Tip

See Setting up a Digital Demodulation Measurement to learn how to use I+jQ for Digital Demodulation Measurements.

Selecting I+jQ(Ch1+j*Ch2) allows you to measure and analyze I and Q data signals directly. The quadrature mixer is removed from the analyzer's signal path as shown in the Vector Signal Analyzer Block Diagram. With this configuration, you must provide the in-phase (called I or Real) signal on Channel 1 and the quadrature-phase (called Q or Imaginary) signal on Channel 2.

You can also make RF measurements using an external quadrature down converter by connecting the I/Q outputs to a 2-channel 89610A. "External" refers to measurement hardware that is not controlled by the analyzer--for example, an Agilent 71910A Wideband Receiver with I and Q outputs. The measurement and configuration settings used by the external quadrature down converter are input to the analyzer using External Frequency Calibration.

If you use an Agilent E4406 with baseband IQ inputs as your measurement hardware, no external down converter is required.

Ch1+j*Ch2 Measurements and Recordings

Signals that are recorded in I+jQ mode should be played back in I+jQ mode. While they can be played back as 2 separate channels, the time corrections will not in general be consistent. 2-channel Baseband recordings, however, can be played back in I+jQ mode and time corrections will be accurate.

See also

I+jQ Frequency Spectrum

I+jQ Span and Frequency Information

I+jQ Measurement Tips

Setting up an I+jQ Measurement with External Quadrature Down Converter


I+jQ Frequency Spectrum

The frequency spectrum you see when you select the I+jQ(Ch1+j*Ch2) input channel contains both positive and negative frequencies. The negative frequencies are a result of the baseband frequency spectrum of the I and Q signals which has energy at both the positive and negative frequencies. The Ch1+jCh2 Spectrum display effectively shows the output spectrum of a mixer whose local oscillator set to 0 Hz (dc) and input is the baseband I/Q signal.

When you use an external converter, set the external center frequency to match the measurement center frequency and enable Use External Down Converter. If you do not enable Use External Down Converter, the displayed frequency axis represents frequencies relative to the center frequency at the down converter and not the measurement's absolute center frequency.

Note

The External Down Converter IF must be set to 0 Hz.

See also

About I+jQ(Ch1+j*Ch2) Measurements

I+jQ Span and Frequency Information

I+jQ Measurement Tips

Setting up an I+jQ Measurement with External Quadrature Down Converter


I+jQ Span and Frequency Information

This topic provides span and frequency information that is unique to 2-channel I+jQ(Ch1+j*Ch2) measurements. The information applies to two different measurement configurations; the first uses only the baseband analyzer and the second uses the baseband analyzer with an external quadrature down converter. See About Frequency for more information about the frequency and span parameters.

Two-Channel I+jQ Measurement Span and Frequency Information.

The following frequency and span information applies to 2-channel I+jQ(Ch1+j*Ch2) measurements for the 89600 baseband analyzer.

The following figure shows the span and frequency interrelationships for a zoomed measurement in the negative frequency side of the analyzers full span.

Span

The span can be adjusted arbitrarily to the maximum span which is equal to double the maximum span of a single channel measurement. For the 89610A VSA using two E1438 ADCs, the maximum span is equal to 78.125 MHz (twice the single channel span).

Max Span = 2 × (Single Channel Bandwidth)

Center Frequency (Fc)

The center frequency can be adjusted arbitrarily within the analyzer's maximum span (Max Span) limits. Trace data will be blanked for measurement spans that exceed the analyzer's Max Span limits. The center frequency (Fc) may be adjusted within the following limits.

Fc Range = ± (Max Span/2)

Two-Channel I+jQ Measurement Span and Frequency Information with External Down converter.

The following frequency and span information applies to two-channel I+jQ(Ch1+j*Ch2) measurements using the 89600 baseband analyzer with an external quadrature down converter. The external quadrature down converter allows you to extend the baseband analyzer I/Q measurement capabilities to include RF signals.

The analyzer's external down converter interface is through the External Frequency dialog box. You provide input data for these external down converter parameters: the external center frequency, the Intermediate Frequency (IF), and the External Bandwidth. You must then select the Use External Down Converter check box to apply the settings to the measurement. If you do not enable Use External Down Converter, the displayed frequency axis represents frequencies relative to the center frequency at the down converter and not the absolute center frequency.

Note

The External Down converter IF must be set to 0 Hz.

The following figure shows the span and frequency interrelationships using the 89610 baseband VSA with external down converter making a zoomed measurement at Fc(zoomed). In this example the external down converter bandwidth is greater than the analyzer maximum span.

Span

The span can be adjusted arbitrarily within the maximum measurement span which is analyzer hardware and external down converter dependent. The maximum measurement span is the smaller bandwidth of the analyzer full span and the external down converter bandwidth. Trace data is blanked for any frequencies outside the maximum measurement span. For example, if an external down converter with an external bandwidth (ExtBW) of 100 MHz is used with the 89610A baseband VSA (with an Max Span of 78.125 MHz), the maximum span for a 2-channel I+jQ measurement would be 78.125 MHz.

Max Span = 2 × (89600 VSA Single Channel Bandwidth) or
External Converter bandwidth, whichever is smaller

Center Frequency (Fc):

The center frequency (Fc) can be arbitrarily adjusted within the maximum measurement span, which is analyzer hardware and external down converter dependent. To show the absolute center frequency you must enter the down converter center frequency and enable Use External Down Converter. Otherwise the displayed frequency axis represents frequencies relative to the center frequency at the down converter and not the absolute measurement frequency.

•	Center frequency (Fc) range when the External Down converter bandwidth (Ext BW) is greater than or equal to analyzer full span

(ExtFc − Full Span/2) ≤ Fc Range ≤ (ExtFc + Full Span/2)

•	Center frequency (Fc) range when the analyzer full span is greater than or equal to External Down converter bandwidth (ExtBW)

(ExtFc − ExtBW/2) ≤ Fc Range ≤ (ExtFc + ExtBW/2)

See also

About I+jQ(Ch1+j*Ch2) Measurements

I+jQ Frequency Spectrum

I+jQ Measurement Tips

Setting up an I+jQ Measurement with External Quadrature Down Converter


I+jQ Measurement Tips

The following information applies for I+jQ(Ch1+j*Ch2) measurements.

•	The maximum frequency span the baseband analyzer can measure is double the single channel span.

•	For accurate results, you MUST use the same configuration for the Channel 1 and Channel 2 inputs. In other words, the Range and Input settings MUST be identical for both channels.

•	Selecting I+jQ(Ch1+j*Ch2) automatically selects DC coupling for both input channels. You want to use DC coupling because AC coupling creates a notch in the middle of your spectrum. Furthermore, AC coupling causes larger errors in most digitally demodulated measurements.

•	When using an external quadrature down converter you must set the External Intermediate Frequency to 0 Hz (Utilities > Calibration > External Frequency tab).

See also

About I+jQ(Ch1+j*Ch2) Measurements

I+jQ Frequency Spectrum

I+jQ Span and Frequency Information

Setting up an I+jQ Measurement with External Quadrature Down converter


Setting up an I+jQ Measurement with External Quadrature Down Converter

The I/Q external quadrature down converter allows you make I and Q measurements on RF signals.

The measurement setup requires a 2-channel 89600 baseband analyzer in I+jQ(Ch1+j*Ch2) input mode with the Ch1 and Ch2 inputs connected to I and Q outputs of an external I/Q quadrature down converter.

For the procedure for setting up an I+jQ measurement using the 2-channel 89610 VSA and external quadrature down converter, see Calibrating a Two-Channel 89610 with External Quadrature Down Converter.

See also

Digital Demodulation Block Diagram

I+jQ Frequency Spectrum

I+jQ Span and Frequency Information

I+jQ Measurement Tips

About I+jQ(Ch1+j*Ch2) Measurements

Setting Up an 89611 with External Down Converter

Setting Up an 89640 with External Down Converter


About Windowing

Windowing solves the problem of leakage when converting signals from the time domain into the frequency domain. Windowing is the process of multiplying the time record by a weighting function, or a window, to force a signal to be periodic in the time record. Windowing weights the data in the time domain to improve accuracy in the frequency domain.

Note

To learn more about Windowing concepts, see Windowing in the VSA Concepts online help.

Tip

When time gating is enabled, there are two time records: a main time record and a gate time record. You can select the same window or different windows for both of these time records. To select a window for the main time record, click MeasSetup > ResBW. To select a window for the gate time record, click MeasSetup > Time.

See also

Window Types

Window Shapefactor and Equivalent Noise BW

Windowing Frequency Response

Window Bandwidth


Window Types

Menu Path: MeasSetup > ResBW (for the main time record)
Or: MeasSetup > Time (for the gate time record)

The analyzer provides the following types of windows.

Window	Common Uses
Uniform	Transient and self-windowing data.
Hanning	General purpose.
Gaussian top	High dynamic range.
Flat top	High amplitude accuracy.
Uniform Window

The uniform window (also called the rectangular window) has the same effect as that of not applying a window. Use this window when leakage is not a concern, such as observing an entire transient signal.

The uniform window has a rectangular shape and does not attenuate any portion of the time record. It weights all parts of the time record equally. Because the uniform window does not force the signal to appear periodic in the time record, it is generally used only with functions that are already periodic within a time record, such as transients and bursts.

For sine waves that are exactly periodic within a time record, the uniform window measures the amplitude exactly (to within hardware specifications).

The uniform window is sometimes called a transient or boxcar window. The uniform window is not suitable for Scalar measurements.

Hanning Window

The Hanning window attenuates the input signal at both ends of the time record to zero. This forces the signal to appear periodic. The Hanning window offers good frequency resolution at the expense of some amplitude accuracy.

This window is typically used for broadband signals such as random noise. This window should not be used for burst or chirp source types or other strictly periodic signals. The Hanning window is sometimes called the Hann window or random window.

Gaussian Window

The Gaussian (high dynamic range) window offers less amplitude accuracy, slightly higher frequency resolution, and much lower sidelobes than the Hanning window. The Gaussian window provides higher dynamic range than other windows because it has much lower sidelobes. It is used for general-purpose measurements and when high dynamic range is required (such as when time averaging).

FlatTop Window

The Flattop window is the default window for FFT measurements. The flat top window provides better amplitude accuracy with a tradeoff in frequency resolution. Typically, this window is used for narrowband signals when you must measure the amplitude of a particular frequency component with great accuracy--for example, when using a fixed-sine source. This window should not be used for burst or chirp source types or other strictly periodic signals. The flat top window is sometimes called a sinusoidal window.

See also

Windowing Overview

About Windowing

Window Shapefactor and Equivalent Noise BW

Windowing Frequency Response

Window Bandwidth


Window Shapefactor and Equivalent Noise BW

The following table shows a performance summary of the different types of windows supported by this analyzer. Following the table is a section that describes the terms shapefactor and equivalent noise bandwidth.

WINDOW SUMMARY

Parameter	Uniform	Hanning	Gaussian Top	Flat  Top
Leakage Performance	Poor	Relatively Good	Best	Good
Frequency Resolution: main length fixed	Poor**	Relatively Good	Good	Poor
Frequency Resolution: RBW fixed	Poor**	Good	Good	Best
Normalized Equivalent Noise BW	1.00 Hz-sec	1.50 Hz-sec	2.215 Hz-sec	3.8194 Hz-sec
3 dB BW	0.8844 Hz-sec	1.438 Hz-sec	2.091 Hz-sec	3.767 Hz-sec
Window ShapeFactor	716:1	9.1:1	4.0:1	2.45:1
Maximum Amp. Error*	3.92 (dB)	1.42 (dB)	0.68 (dB)	< 0.01 (dB)
Highest Sidelobe	−13 (dB)	−31 (dB)	−125 (dB)	−95 (dB)
Sidelobe Fall Off	−20 dB /decade	−60 dB /decade	−20 dB /decade	−20 dB /decade
*	The maximum amplitude error occurs when a signal is halfway between frequency bins.
**	Frequency resolution is best for equal amplitude signals (for example, two closely spaced sine waves), but poor in general because of the large sidelobes.

Window Shapefactor & Equivalent Noise BW

Two terms in the above table may be new to you:

•	Window shapefactor.

•	Equivalent noise bandwidth.

Window shapefactor is a frequency ratio. It is the ratio of the frequency at −3dB to the frequency at −60dB. Window shapefactor is sometimes called window selectivity.

Equivalent noise bandwidth (ENBW) compares the window to an ideal, rectangular filter. It is the equivalent width of a rectangular filter that passes the same amount of white noise as the window. The table shows the normalized ENBW. To compute the ENBW, divide by the time-record length. For example, a Hanning window on a 0.5 second time record would have an ENBW of 3 Hz (1.5 Hz−sec/0.5 sec). Notice that the ENBW is slightly larger than the 3 dB bandwidth.

Note

This analyzer uses the value of the equivalent noise bandwidth for its resolution bandwidth (RBW).


Windowing Frequency Response

This analyzer functions as if the input signal were applied to a parallel bank of narrow-band filters (the number corresponding to the number of frequency points). The illustrations below show the frequency-domain response of a single filter when using uniform, Hanning, Gaussian top, or flattop windows.

Tip

To learn more about Windowing concepts, see Windowing in the VSA Concepts online help.

The left side of each illustration represents the center of each filter. Because the filters are symmetrical, we've shown only one side of each filter response (the other side is a mirror image). The horizontal axis is normalized to 1/T.

Think of each drawing as a template. If you position a sine frequency at the exact center of the filter, more of a sine wave's energy appears in the center bin. Some of its energy also appears in other bins. The amount of energy that spills into adjacent bins depends on the type of window you use. Frequency resolution is determined by the width of the main lobe. The Hanning window provides better frequency resolution for a fixed time record length while the Flattop window has good frequency resolution for a fixed resolution bandwidth.

Frequency Response of Uniform Window

Frequency Response of Flattop Window

Frequency Response of Gaussian Window

Frequency Response of Hanning Window

Window Comparison (for a fixed time-record length)


Window Bandwidth

In most analyzers the final IF filter determines the resolution bandwidth. In the Agilent 89600 series analyzers the window type you select shapes the resolution bandwidth filter shape. And the window type, along with the time record length, determines the width of the resolution bandwidth filter. Therefore, for a given window type, a change in resolution bandwidth will directly affect the time record length. Conversely, any change to time record length will cause a change in resolution bandwidth.

Window Bandwidth

Flattop	3.8193596
Gaussian top	2.21534968
Hanning	1.5
Uniform	1.0
Important relationships

Window bandwidth represents the noise equivalent bandwidth of a window's filter shape and affects the resolution bandwidth and time record length.

Some useful equations help explain the relationship between time record length and time record size:


About Spectrograms

A spectrogram display provides another method of looking at trace data. In a spectrogram, each trace occupies a single, horizontal line (one pixel high) on the display. The Y-axis value is indicated by color. For the Spectrum Analyzer application, each line in the spectrogram represents a single sweep.

The following actions clear the spectrogram buffer and start a new spectrogram:

•	Restarting a measurement

•	Turning averaging on or off

•	Changing the average type

•	Selecting new measurement data

•	Changing the number of points in the measurement data

•	Changing the buffer depth of the spectrogram

Note that changing the Trace Format (coordinates) or Scaling does not clear the buffer.

Note

In Spectrum Analyzer application only, the spectrogram buffer is cleared when you resize application's window if the number of frequency points is determined by display size. This is the default operation; to prevent this happening, clear the Same as display check box next to Frequency Points on the ResBw tab of the MeasSetup Properties dialog box.

A spectrogram flows from the bottom to the top of the display. The most recent trace is the 1st row of pixels at the bottom of the display, the previous trace is the 2nd row of pixels on the bottom of the display, and so forth.

The number of traces required to fill the display depends on the size of the display area. To maximize the number of traces displayed, maximize the 89600 window and set the Display Layout to Single. To further increase the display area, turn off the marker and menu displays.

Note

For any trace data that includes two Y-axis values for one X-axis value, the spectrogram assigns the color associated with the larger of the two values. For example, a spectrogram in the Spectrum Analyzer application always displays the max for each min/max pairs.

The following display shows a spectrogram in trace A. For this example, the spectrogram displays approximately 150 traces. Click on the fields to the left of the spectrogram for information on what each field means.

For instructions on setting up a spectrogram display, see Spectrogram Displays in the tutorial section.

For reference information, see Spectrogram Properties Dialog Box.

Colors in a Spectrogram

With spectrogram displays, colors indicate vertical displacement. Different colors represent different y-axis values. The color bar at the left side of the display indicates the color scheme used.

The analyzer displays the current scale next to the color bar. The top color in the color bar represents Y Top; the bottom color represents Y Bottom.

Trace data for spectrograms

You can display a spectrogram for all trace data except Error/Symbol Table.

Trace formats for spectrograms

The spectrogram display does not allow these formats:

•	I-Q and Constellation

•	Eye Diagrams

•	Trellis Diagrams

If you turn on spectrogram for these trace formats, the analyzer stores the information in the buffer, but displays only the latest trace. You can pause the measurement and use the Trace Select marker to see previous traces. Or you can select a trace format that does allow the spectrogram display.

Saving and recalling spectrograms

Use Save Trace and Recall Trace to save and recall spectrograms. Save Trace saves whatever is displayed in the active trace. When you recall a spectrogram, it is put in a data register.

Math functions with spectrograms

For a math function to produce a spectrogram that contains multiple traces, the math function must be dynamic. A math function is dynamic if any operand is dynamic. An operand is dynamic if it is updated with each measurement.

For example, a data register or math constant is not dynamic, because they are not updated with each measurement. Measurement data (such as spectrum ch1) is dynamic, because it is updated with each measurement.

Therefore, if your math function includes, for example, the spectrum ch1 operand, and you display the math function with spectrogram turned on, you will see a spectrogram display that contains multiple traces. However, if your math function includes, for example, only data registers and math constants, and you display the math function with spectrogram turned on, you will see a spectrogram display that contains only a single trace.

For additional details, see online help for creating math functions.


Optimizing Spectrogram Performance

You can increase the speed of spectrogram displays by doing one or more of the following:

•	Use 16-bit color rather than 24-bit color.

•	Decrease the width of your display (resize the 89600 analyzer window).

•	Increase the memory on your video card.

•	Increase the amount of virtual memory in your computer.

If you change the number of frequency points or the buffer depth, the amount of memory required for the spectrogram also changes. If the amount of memory required exceeds the available memory, swapping occurs--the analyzer must access the disk during the measurement, slowing the measurement.


Spectrogram Properties Dialog Box

Menu Path: Trace > Spectrogram

From this dialog box you set up the spectrogram display. The parameters include:

•	Buffer Depth

•	Color Count

•	Enhance

•	Map Color Scheme

•	Show Spectrogram

•	Threshold

For information about spectrograms, see About Spectrograms.

See also

About Spectrograms


Buffer Depth (Spectrogram)

Menu Path: Trace > Spectrogram

Buffer depth specifies the maximum number of individual traces that will be:

•	stored when you save the spectrogram.

•	displayed when you refresh the display.

When you change the value for buffer depth, the analyzer empties the buffer and the currently displayed spectrogram is deleted.

The buffer depth is limited by the amount of memory available on your computer.

The trace buffer stores traces from the last N measurements (where N is the buffer depth) or, if fast averaging is on, from the last N average updates. Trace 1 is the oldest trace in the buffer. Trace N is the newest trace in the buffer.

Note

The spectrogram display can show more traces than are stored in the buffer, but when you save the spectrogram, only the number of traces you specify with Buffer Depth are saved. And you can set markers only for traces in the buffer.

To fill the trace buffer with spectrogram data and display the spectrogram, select the Show Spectrogram check box in the Spectrogram dialog box or the icon [image] in the spectrogram toolbar.


Color Count (Spectrogram)

Menu Path: Trace > Spectrogram

Color Count specifies the number of colors used for the spectrogram display. The number of colors determines the resolution of the trace. For finer resolution, increase the Color Count. For coarser resolution, decrease the Color Count.

The maximum (and default) value is 64. When you specify a value less than 64, the display uses that number of colors distributed across the active color map.

The following figure shows the color bar with Color Count set to 64, 16, and 8.

The best way to see the effect of Color Count is to look at a spectrogram with Color Count set to different values. With a spectrogram displayed, follow these steps:

1.	Pause the measurement (click [image]).

2.	Click Trace, Spectrogram.

3.	Click in the Color Count box, type 8, and click OK.

4.	Notice the change in the displayed spectrogram.


Enhance (Spectrogram)

Menu Path: Trace > Spectrogram

The value set for Enhance determines how colors are distributed in the color bar for spectrogram displays. The default value is 50% (even distribution of colors in the color bar).

You can improve some spectrogram displays by changing the enhancement. By changing the enhancement, you may be able to highlight obscure signals or obscure highlighted signals.

You specify enhancement as a percentage, from 0% to 100%. The percentage you specify is used to redistribute the colors in the color bar, as shown in the following illustration. (For this example, all 64 colors are used.)

Notice from the previous illustration that a percentage of 50% evenly (linearly) distributes the colors in the color bar. A percentage less than 50 exponentially compresses the colors into the top of the color bar, whereas a percentage greater than 50 exponentially compresses the colors into the bottom of the color bar.


Map Color (Spectrogram)
Map Color Scheme (Spectrogram)

Menu Path: Trace > Spectrogram

The color map determines the spectrum of colors used for the spectrogram display.

The standard color maps consist of 64 colors. The number of colors used by a spectrogram display is set by Color Count. For example, if Color Count is 64, all colors in the color map are used; if Color Count is 10, the display uses 10 colors spread across the active color map.

Different color maps offer different perspectives. Essential information may be buried, or obscure, in one color map but prominent in another.

You can select from four standard color maps or define your own map. The following illustration shows the four standard maps:

1.	Color Normal

2.	Color Reverse

3.	Grey Normal

4.	Grey Reverse

Color Normal is the default color map. This color map consists of a spectrum of 64 colors. The peak amplitude is red; the minimum amplitude is blue. The remaining 62 colors are generated by linearly changing the hue between red and blue.

Color Reverse is identical to color normal, except the colors are reversed. In this case, the peak amplitude is blue; the minimum amplitude is red.

Grey Normal consists of 64 shades of grey. The peak amplitude is the lightest shade of grey; the minimum amplitude is the darkest shade of grey.

Grey Reverse is identical to grey normal, except the shades of grey are reversed. In this case, the peak amplitude is assigned the darkest shade of grey, the minimum amplitude the lightest shade of grey.

User lets you use a custom color map. You can recall a previously-defined map or define a new one. To define a new map, either click Edit in the Spectrogram Properties dialog box or click Display, Appearance, and select the User Map Color tab.


Show Spectrogram

Menu Path: Trace > Spectrogram

The Show Spectrogram check box enables or disables the spectrogram display for all active traces. Select the check box to turn on spectrograms; clear the check box to turn off spectrograms.

When you enable the spectrogram display (select the check box), the currently trace becomes trace 1 in the spectrogram.

When you disable the spectrogram display (clear the check box), the analyzer clears the trace buffer of all data.

Note

Disabling a spectrogram display clears any measurement data in the trace buffer.


Threshold (Spectrogram)

Menu Path: Trace > Spectrogram

Sets the threshold for the currently selected spectrogram display. This feature is useful for removing noise-floor clutter from the spectrogram display.

When you specify a threshold, the analyzer displays colors at or above the threshold; below the threshold, the analyzer uses the bottom color in the color bar.

You specify the threshold as a percentage of the height of the color bar. Thus, with a threshold of 50%, the analyzer displays only those colors in the upper half of the color bar. Note that a threshold of 100% displays no spectrogram, because the spectrogram never exceeds the threshold.

The following illustration shows the color bar with threshold set at 0, 25, 50 and 75 (from left to right).

The next illustration shows two displays of a pulsed signal. The display on the left has threshold set at 0. For the display on the right, threshold was set to 50. The threshold setting removed the noise that cluttered the left display.


Spectrogram duration

This field displays the time difference between the beginning of the top trace and the end of the bottom trace in the spectrogram display.

Note that if you pause a measurement, the time that the measurement is paused is included in the duration.

If you are playing back a recording with looping turned on, the analyzer approximates the total time for the measurement by adding the times for each repeat or partial repeat of the recording.


Color bar

The color bar displays the colors in the color map. The top color corresponds to Y Top. The bottom color corresponds to Y Bottom,


Y Top

This field indicates the y-axis maximum value.


Y Bottom

This field indicates the y-axis minimum value.


Spectrogram toolbar

This toolbar allows you to turn the spectrogram display on or off, set the enhance level, and change the map color scheme.


About Source

(Vector Signal Analyzer application only.)

The Source feature links the analyzer to a supported external signal generator. The principal purpose is to allow you to record a time domain signal using the analyzer, then reproduce it using a signal generator that supports arbitrary IQ modulation. A few convenience features were added to supplement this capability.

From the 89600 interface, you can do these things with the signal generator:

•	Enable or disable control of the generator by the 89600

•	Change the carrier frequency and the amplitude level

•	Turn the arbitrary IQ modulation on or off

•	Create a named Arbitrary Waveform, encapsulating all or a portion of a recorded waveform, which may be played back by the source. The source need not be present to create the waveform.

•	Choose a previously created Arbitrary Waveform to download to the source for playback

•	Cause the source carrier frequency to track the analyzer center frequency

Note

Supported sources have many other capabilities. To use these capabilities, disable 89600 source control.

When you enable 89600 source control, the source state is reset, which may destroy any setup you have made. Be sure to save any source setup that you wish to go back to after using 89600 source control. The source control defaults to disabled when you start the Vector Signal Analyzer application.

The arbitrary source capability can reproduce any signal recorded using zoom mode, but it cannot reproduce baseband signals. This is because the arbitrary waveform generator is not routed directly to the source output, but is used to modulate a carrier. In zoom mode, the analyzer translates the frequency span being measured to 0 Hz by mixing it with a complex digital local oscillator, producing complex time data. The complex data is downloaded via the source link to the dual arbitrary modulation generators of the source, where the signal modulates a carrier at a chosen RF frequency.

This method of reproducing arbitrary signals allows you to record a signal at one center frequency and reproduce the signal using any carrier frequency you choose. The signal spectrum remains the same relative to the new carrier frequency, and demodulating the signal produces the same results. For example, you can record a portion of a live, digitally modulated signal at one channel frequency and replay it at another. This is useful if the device you wish to stimulate has different frequency requirements than a conveniently available signal generator.

Tip

When playing back arbitrary waveforms using a supported vector signal generator, you can connect the "Event 1" output on the back of the generator to the "Ext Trigger" input of the E1438 or E1439. Then set triggering to external and your measurement will be synchronized with the start of the arbitrary modulation data. Use Trigger delay to see different parts of the played-back signal.

See also

Supported Hardware Configurations

Time Data

Creating an Arb Waveform from a Recording

Creating an Arb Waveform from a Data Register


Arbitrary IQ Modulation

The 89600 source link enables reproduction of a recorded waveform by a source that supports arbitrary IQ modulation, for example, the Agilent ESG-D series generators with the Dual Arbitrary Waveform Generator (option UND).

Arbitrary IQ modulation is performed by a modulator that conceptually consists of a sine and a cosine generator at the same frequency, both of which are amplitude modulated, and are then combined. The amplitude modulation is done in each case by an arbitrary waveform generator, or arb. The arb that modulates the sine is called the in-phase, or I modulation, and the arb that modulates the cosine is called the quadrature, or Q modulation. The complete modulated waveform can reproduce any band-limited signal, centered on the carrier frequency.

An arbitrary waveform generator consists of a digital-to-analog converter (DAC) and a data source. The data source is clocked into the DAC using a variable-rate clock. You generally want to clock the data source at the sample rate used to record the data. This produces a signal with the same spectrum as the original signal, but also containing images of the spectrum centered at multiples of the sample rate. (For DAC-driven IQ modulation, the images are offset from the carrier at multiples of the sample rate.) These images are caused because the DAC produces a stair-step connecting successive samples, instead of smoothly interpolating between them.

The following illustrations show the original signal (I or Q), samples of the signal that form the DAC data source, the stair-step signal at the DAC output, and the spectrum of the carrier modulated by the I and Q DAC outputs. The bandwidth of the reconstruction filter is wide enough to include the higher-frequency images. Note that the sample period for the original signal and the DAC output are equal.

You must use a reconstruction filter to eliminate the unwanted, higher-frequency portion of the signal. Arbitrary waveform generators may only have a small set of reconstruction filters to choose from. Usually, you choose the one with the smallest bandwidth capable of passing the frequencies of interest. In most cases this still allows some unwanted spectral images to pass. To reproduce the recorded signal with highest fidelity, you can resample the data, mathematically producing an equivalent data record at a higher sample rate. The sample rate chosen is a little greater that twice the bandwidth of the reconstruction filter, so that the images now fall outside the filter's passband. The filter now passed only the interesting portion of the spectrum. The cost of this greater signal fidelity is that it requires more memory to store the DAC data. The following illustrations show the resampled signal and the spectrum of the resampled signal. Note that the sample period is significantly smaller than that in the previous illustrations and that the higher-frequency images have been filtered out.

The 89600 source feature allows downloading data to an arbitrary IQ modulation source either with the original sample rate to conserve memory, or resampled for higher signal fidelity.

Note

Any of the newer Vector Signal Generators (such as the Agilent E4438C or E8267C), equipped with a baseband generator, performs resampling and filtering internally, so the data can be downloaded at the original sample rate and still be replayed with high signal fidelity.

Another distortion caused when you replay signal samples using a DAC is that the spectrum of the DAC output droops in amplitude at higher frequencies, compared to the spectrum of the original signal. This amplitude droop follows the shape of the function sin(pf)/(pf) and is more pronounced at frequencies farther from the carrier. The source data is predistorted before downloading to the source to correct for this droop.

See also

About Source


Connecting an External Source

For information on connecting and configuring a source, see the Installation and Service Guide.

At startup, the 89600 VSA application will automatically locate all supported sources on the GPIB bus. If more than one source is available, specify a source by clicking Utilities, Hardware, Source and the source you want to use.

It is highly recommended that you lock the source reference frequency to the measurement hardware frequency reference.


Creating an Arb Waveform from a Recording

These are the basic steps to create a new arb waveform.

1.	Display the desired signal in the analyzer display.

2.	Record the signal.

3.	During playback, set the start and stop time to mark the portion of the signal you wish to have the source reproduce.

4.	Click Source > Control > New.

5.	Click Recording > Chan 1. Enter a name for the file. Click Ok.

6.	Click Input/Data from/Hardware.

7.	In the Source Control dialog box, click Enabled. Click the box labeled Arb Waveform and select your filename from the list.

8.	Set the amplitude and carrier frequency as desired.

Steps 1 through 6 do not require that a source be present.

You can replace steps 1 and 2 by recalling a recording.

Here are some things to remember when you are creating an arb waveform:

•	You can use only the currently active recording. If you want to use a previously recorded signal, you must first recall the recording.

•	The portion of the recording you want to use is delimited by the start and stop time in the Player. If you do not set these times, the whole recording is used.

See also

Creating an Arb Waveform from a Data Register


Creating an Arb Waveform from a Data Register

If you have a time record that is periodic (the end of the time record ties cleanly back to the beginning without discontinuities) you can copy it to a data register and use that to create an arb source data file. Then when you download it, use the minimum memory sampling model, and the playback will be periodic. Here's an example:

1.	Make sure the analyzer hardware setup includes a source.

2.	Set analyzer center frequency to 18 MHz, span to 5 MHz, and range to 0 dBm.

3.	Set up these ResBW parameters:

ResBW mode: Arbitrary
Window: Uniform
Frequency points: 801

4.	Set a sine-wave source to 0 dBm output, frequency 17.375 MHz, and connect to input channel 1. (This works better if the source frequency reference is locked to the analyzer.)

5.	Click in the Ch1 Main Time trace area to activate it, then click File > Copy Trace > D1.

6.	Click Source > Control.

7.	In the Source Control dialog, click New. In the Define New Arb dialog, set the name to Sine 1, select Register D1 as the data source, and click OK.

8.	Back in the Source Control dialog, click on the Arb tab and choose minimum memory. Be sure that the Window ends box is cleared. Click on the Control tab again.

9.	Select the Enable box. Choose output Arb > Arb waveform Sine 1 > Carrier Frequency 18 MHz > Amplitude 0 dBm.

You can now see the sine wave created by the carrier being modulated by a 625 kHz complex exponential. This produces a single-sideband suppressed-carrier tone at 17.375 MHz. Because the modulator is not perfect, you will see a small amount of the carrier and the upper sideband leaking through. The modulation is periodic so there is no spectral splatter from discontinuities.

See also

Creating an Arb Waveform from a Recording


Source Error Messages

Downloading data to the source may result in these error messages.

•	There was insufficient arb source memory to complete the download. Data was truncated.

The amount of arb source data that can be downloaded to the source depends on how much memory the source has and if it has other, protected arbitrary data in memory. If the remaining memory is insufficient to hold the downloaded arb data, the software will download as much as possible and truncate the rest. To download more of a waveform, use minimum memory mode. Also, sources like the ESG-D allow you to view the arb data memory (as if it were a directory) and to eliminate files of arb data. Cleaning out unwanted files allows bigger downloads.

•	Arb source is unfiltered.

The sample rate of the arb source data precludes using the widest reconstruction filter in the source, or the spectrum would be truncated. Therefore, no filter is used. In this case there is no difference between maximum fidelity and minimum memory when downloading. Some sources allow you to add an external analog filter.

•	Arb waveform bandwidth was reduced due to the maximum arb source sample rate.

You attempted to download arb source data whose sample rate exceeds the maximum sample rate available in the source that is being used to play it back. If the data sample rate is less than twice the maximum source sample rate, the data is filtered and resampled to the maximum source sample rate. This eliminates some of the spectrum, but the rest plays back accurately. (Resampling is done during download; the original data is left as it was.)

•	Arb waveform requires unsupported arb source sample rate.

You attempted to download arb source data whose sample rate exceeds twice the maximum sample rate available in the source that is being used to play it back. The download is aborted, and this error is displayed.


Output Menu (Source)

(Vector Signal Analyzer application only)

Menu Path: Source > Output

This menu lets you select a waveform and control the signal generator output. The menu includes three selections: Off, Sine, and Arb waveform.

Off turns the signal generator's RF Output to Off.

Note that this does not enable the front panel keys. You must clear the Enable box on the Control tab to return the signal generator to local control and enable the front panel keys.

Sine specifies that a sine waveform be generated and turns on the signal generator's RF Output. The Amplitude and Frequency are set to the values specified in the Source Control dialog box.

Arb waveform performs one of three actions:

•	If the field lists "New Arb Waveform…", clicking it brings up the Define New Arb dialog box.

•	If the field lists any other waveform name, clicking it specifies that waveform be generated and turns on the signal generator RF output.

•	If you click the arrow at the right side of the field, it displays a list of available arbitrary waveforms. When you click an item in the list, that waveform is downloaded to the signal generator. If you have not previously created waveforms, the only item in the list is "New Arb Waveform…".

Note that these controls (except New Arb Waveform) are inactive unless the Enable check box is selected in the Source Control tab.


Arb Waveforms Dialog Box (Source)

(Vector Signal Analyzer application only)

Menu Path: Source > Arb Waveforms…

Use the Arb Waveforms dialog box to manage your user-defined arbitrary waveforms. You can view, select, create, and delete waveforms from this dialog box.

New	Create a new arbitrary waveform.

Delete	Delete the highlighted waveform from the list.

See also

Define New Arb dialog box


Define New Arb dialog box (Source)

(Vector Signal Analyzer application only)

Menu Path:	Source > Arb Waveforms > New

Or	Source > Output > New Arb Waveforms

Or	Source > Output > New Arb Waveforms > New Arb Waveforms

Or	Source > Control > New

From this dialog box you can define and save arbitrary waveform data.

Note that the OK button is available only if the data for the selected recording or data register is valid. If the data is invalid, the OK button is greyed and nothing happens when you click it.

Note

The arbitrary source capability can reproduce any signal recorded using zoom mode, but it cannot reproduce baseband signals.

Name

Enter a file name for your new arbitrary waveform. The analyzer saves the file with the extension ARB.

Recording

Select a recording as the source for the arbitrary waveform data.

If you specify Recording, the waveform will be taken from the analysis region that you set in the Player. The length of the waveform may be limited by the capabilities of the source at the time the data is used.

Register

Select a data register as the source for the arbitrary waveform data.

When specify Register, the data register box becomes active so that you can specify which data register you want to use.

The length of the waveform is limited by the capabilities of the source at the time the data is used.


Arb Tab (Source)

(Vector Signal Analyzer application only)

Menu Path: Source > Control

The Arb tab lets you configure the signal generator's arbitrary waveform generator playback options, select a sampling model, and turn Window Ends on or off.

Sampling Model

You can choose between two sampling models, Maximum Fidelity or Minimum Memory. These selections determine how much memory is required in the signal generators data registers to reproduce the arbitrary waveform.

Note

For the newer Vector Signal Generators (such as the Agilent  E4438C or E8267C), there is no difference between Minimum Memory and Maximum Fidelity.

Maximum Fidelity requires more signal generator memory than does Minimum Memory. The spectrum of the reproduced waveform is limited to the span at which it was recorded. For long time records, Maximum Fidelity may overflow the data capacity of the signal generators memory. In these cases, you should use Minimum Memory.

Minimum Memory requires less signal generator memory than does Maximum Fidelity. Minimum Memory will reproduce the waveforms spectrum accurately within the recorded bandwidth, but there can be other significant spectral energy outside this bandwidth.

Window Ends

Window Ends limits spectral splatter that would result from the discontinuity as the source wraps from the end of the arb data back to the beginning.

If the Window Ends check box is selected, the beginning and end of the active ArbSource data is amplitude-modulated by a half-cycle of a raised cosine.

Use Window Ends if the recorded signal amplitudes at the ends are significantly different. If the data is self-windowing or periodic (with period equal to the time record length) then you may turn this feature off.

See also

Arbitrary IQ Modulation


Control Tab (Source)

(Vector Signal Analyzer application only)

Menu Path: Source > Control

The source control tab allows you to do the following things:

•	Amplitude sets the signal generator RF output signal level.

•	Arb Waveform lets you select an arbitrary waveform.

•	Enabled determines whether the signal generator is controlled from its front panel or the analyzer interface. If the check box is selected, control is from the analyzer interface, and the signal generator front panel is locked. If the check box is cleared, control is from the signal generator front panel.

Note

When you select the Enable check box, the source is reset. Any previous setup may be lost. Be sure to save any setup state that you wish to preserve (using the source's own front panel) before enabling 89600 source control. The source control defaults to disabled when you start the Vector Signal Analyzer application.

•	New brings up the Define New Arb dialog box so that you can define a new arbitrary waveform.

•	Output duplicates operation of the Source Output menu. You can turn the signal off or specify a sine wave or arbitrary waveform output. If you select Sine or Arb, the analyzer turns on the signal generator's RF output. If you select Sine, you can specify the amplitude and frequency settings for the signal generator from other areas of this dialog box. If you select Arb, you must also specify a file name in the Arb Waveform box.

•	Frequency lets you set up the frequency parameters for the sine wave output. These parameters include:

−	Carrier

−	Step

−	Auto Frequency Step

−	Set to Center Freq

−	Offset from Center Freq

−	Track Frequency

See also

Define New Arb dialog box

Arb Waveforms dialog box


Frequency (Source Control dialog box)
Frequency (Source Control)

(Vector Signal Analyzer application only)

Menu Path: Source > Control

From the Frequency area of the source control dialog box you set up the frequency parameters for the signal generator sine wave output.

Carrier

The carrier value specifies the frequency for a sine wave output from the signal generator. You can set the frequency in these ways:

•	Enter a value directly by double clicking the Carrier box and typing the value.

•	Increment or decrement the value using the keyboard arrow keys or the mouse wheel. The increment size is set in the Step box.

•	Click Set to Center Freq. Each time you click this, it sets the carrier frequency to match the analyzer center frequency.

•	If the Track Frequency check box is selected, the source tracks changes in the analyzer's center frequency. When you select the check box, the source's center frequency is changed (if necessary) to maintain the offset specified by the Offset Frequency. This offset is maintained for any changes in the analyzer's center frequency.

When the box is cleared, changing the analyzer's center frequency does not affect the source's center frequency.

Set to Center Freq

Click Set to Center Freq to set the carrier frequency to match the analyzer center frequency.

Step

Changing the value in the Step text box changes the effect of the arrow keys when you change the source frequency. By default, the step is set to Auto, and the arrow keys change the center frequency by steps equal to 1/10 the Frequency Span. When you clear Auto Frequency Step, you can edit the value to any desired frequency. On Preset or startup, Step is set to 25 kHz.

Note

If you change the frequency step value, then later select Automatic Frequency Step, the step size reverts to the default value, even though the value you previously entered is visible. Its greyed appearance indicates that it is not the value actually being used.

Auto Frequency Step

If Auto Frequency Step is selected, the Frequency Step is unavailable, and the analyzer calculates the best step size for the current configuration.

Offset from Center Frequency

If Track Frequency is selected, you specify the sine wave frequency as an offset from the analyzer center frequency. For example, if the analyzer center frequency is 1 GHz and you set Offset from Center Frequency to 10 MHz, the signal generator sine wave frequency is set to 1.01 GHz. If Track Frequency is selected and you enter a carrier frequency directly, the offset frequency is changed so that (carrier frequency minus center frequency) equals offset frequency.

If Track Frequency is cleared, you cannot set Offset From Center Freq.

Note

If Track Frequency is selected and changing the center frequency would cause the carrier frequency to a value out of the source's range, the carrier frequency is set at the limit and the offset is permanently changed to (carrier frequency minus center frequency).

Track Frequency

If Track Frequency is selected, you set the signal generator frequency as an offset from the analyzer's center frequency. If Track Frequency is cleared, you set the signal generator frequency directly from the Carrier box.


About Display Appearance

A major advantage of using the 89600 VSA software is that it uses the Microsoft Windows operating system and follows standard Windows practices. Many of the things you've learned using Microsoft Windows you can apply directly to the 89600 VSA software.

The Getting Started online-help contains an overview of how the 89600 VSA software uses the Microsoft Windows interface, plus the following topics:

•	Activating Traces

•	Viewing Traces

•	Display Layout

•	Dialog Boxes

•	Display Hotspots

You can also customize the display appearance. For reference information, see Display Appearance dialog box. For instructions on how to customize the interface, see Customizing the interface in the tutorial.


Display Appearance Dialog Box

Menu Path: Display > Appearance

The Display Appearance dialog box provides the interface to manipulate the overall look of the display: colors, fonts, and the visibility of menus, the grid, annotations and so forth.

The Display Appearance dialog box has four tabs, each of which control some aspect of the display's appearance. For specific information on the tabs, refer to one of the following:

•	Window tab

•	Trace tab

•	Color tab

•	User Map Color tab

•	Font tab

You can set up the display appearance differently for the Vector Signal Analyzer and the Spectrum Analyzer.


Color Tab (Display Appearance)

Menu Path: Display > Appearance

The Color tab on the Display Appearance menu sets the colors of the items on the display: traces, markers, symbols, the grid, trace background, and annotation background. With the WCDMA option, you also can specify colors for WCDMA symbols.

To change a color, select the item from the list, and click the Color button. A standard Windows color selection dialog box opens, permitting you to select a standard color or to define a custom color for that display feature.

Trace color applies only to the specified trace and its annotation.

Marker, Spectrogram Marker, and Trace Select color applied only to the specified marker for the specified trace.

Symbol color applies only for digital\WCDMA\cdma2000\OFDM demod symbol results displayed in the specified trace.

CDMA XXksym color applies only for WCDMA\cdma2000 demod to the specified Code Layer in the CDP and CDE trace data displays.

Pilot color applies only for OFDM demod Pilot bits in the specified trace.

Average color applies only for OFDM demod RMS EVM results for the specified trace.

Color settings for the other items in the list, Grid, Trace Background, Marker Annotation, Annotation Background, and Indicator, apply to all traces and cannot be set independently for each trace.

Colors are saved as DAP files. (From the File menu, select Save > Save Display Appearance).

Note that you can set up the appearance differently for Vector Signal Analyzer and Spectrum Analyzer because the DAP files are saved in separate directories for the two applications.


Font Tab (Display Appearance)

Menu Path: Display > Appearance

The Font tab on the Display Appearance menu sets the font size and style for Annotations, Status messages, and Marker values. These selections are global; that is, they apply to the entire display, not to the individual traces.


Trace Tab (Display Appearance)

Menu Path: Display > Appearance

The Trace tab on the Display Appearance menu allows you to turn on and off the display grids, annotation, and to choose to display all frequency points. The default setting is checked for grids and annotation and cleared for display all frequency points.

When you clear Show Annotation, all the trace annotation is turned off and the trace grid expands accordingly.

When Show All Frequency Points is cleared, only alias-protected data is displayed. When the check box is checked, all data including aliased frequency points is displayed.


User Map Color tab

Menu Path: Display > Appearance

From this tab you can set up the colors for the user-defined spectrogram map.

User Map Color parameters

Color displays the color palette from which you can select.

Color Count specifies the number of colors in the map. If you reduce the number of colors in a color map, the analyzer uses the number of colors you specify from the bottom of the map. for example, if you set up a user map of 10 colors, then change Color Count to 8, the analyzer discards the top 2 colors in the map and uses the bottom 8 colors.

The count you specify here for a user map is the maximum number of colors that can be used for that map. If you set Color Count in the Spectrogram Properties dialog box to a number greater than the color count specified here, the analyzer uses only the number of colors specified here. If you reduce Color Count in the Spectrogram Properties dialog box, the analyzer uses the top and bottom colors and spreads the remaining colors evenly between the top and bottom.

Color Index indicates the current color in the map. Number 1 is at the bottom of the map. You can define or change a color by specifying its color index.

Copy From lets you copy the map color from another trace to the active trace.

Sample Color shows you the color assigned for the color index.

Sample Map shows the color bar for the currently defined user map.

For instructions on defining a new user map, see Setting up a New User Map.

User Map Color is saved and recalled as part of the display appearance, or you can save and recall the maps individually.


Window Tab (Display Appearance)

Menu Path: Display > Appearance

The Window tab on the Display Appearance dialog box sets the visibility of the Menu and Status bars. By default, both are visible.

Clearing Show Menu makes the menus, toolbars, and macro icon bars invisible. When menus are not visible, the Title bar includes the reminder, "Press ESC for menu".

Clearing Show Status turns off the status bar at the bottom of the display, and allows the grid area to expand.


Setting up a New Map
Setting up a New User Map

To define a new map, follow these steps:

1.	Specify the Color Count (the number of colors in the map).

2.	Set Color Index to 1.

3.	Click Color and select the desired color for the lowest color in the color bar.

4.	Increase the Color Index by 1.

5.	Repeat the previous 2 steps until you have defined all the colors in the map.


About Extended Calibration

(Vector Signal Analyzer application only.)

The Agilent 89600 Extended Calibration Wizard can enhance the measurement accuracy of selected 89600 systems for wide-span measurements. Using an external source, it measures the frequency response of the system at a particular center frequency and range setting. The analyzer then uses this data to correct the time data, digitally filtering the data to compensate for the measured frequency response (both amplitude and phase).

Extended calibration measures amplitude flatness and phase linearity (not the absolute amplitude or phase) of the measurement system, thus improving the accuracy of relative amplitude or relative group delay measurements across the span. This improves the accuracy of any measurement that depends on the measurement system having flat amplitude and linear phase, such as code domain power, error vector magnitude, channel frequency response, am-to-pm conversion, CCDF, or adjacent channel power.

Extended calibration measures the response at the maximum measurement span. After extended calibration, you can change the measurement span without recalibrating, but if you change the center frequency or the range, you may need to recalibrate. This depends on the system you are calibrating.

The Extended Calibration Wizard guides you through the steps of connecting the calibration source to the analyzer hardware, choosing a source level, and specifying a file in which to store the data. It then performs calibration measurements, stores the data, restores the 89600 to the state it was in before calibration, and enables the 89600 to include this IF calibration data in the time data correction.

You can create separate data files for different hardware setups. Then when you change your measurement hardware you can recall the calibration data for a previously calibrated setup.

Extended Calibration Wizard uses the External IF calibration feature of the 89600. See the 89600 online help for External IF calibration for more information. You can view the data produced by Extended calibration by recalling it as a trace. (Click File, Recall, Recall Trace and select the calibration data file.)


Supported Hardware
Supported Hardware for Extended Calibration

The Extended Calibration Wizard requires an external source under the control of the VsaVector application. You must click Utilities >  Hardware >  Source and select one of the supported sources. (See the 89600 help text for more information about setting up the 89600 to control a source.) The supported sources are:

•	ESG Vector Signal Generator E4438C (requires option 001 or 002)

•	PSG Vector Signal Generator E8267C (requires option 001 or 002)

•	ESG-D Series Digital RF Signal Generator (requires option UND)
E4433B, E4432B, E4431B or E4430B

•	ESG-DP Series Digital RF Signal Generator (requires option UND)
E4437B, E4436B, E4435B or E4434B

The Extended Calibration Wizard calibrates only the following 89600 hardware configurations:

•	89611 with Agilent PSA option H70

•	89611 with customer-supplied down converter (tuner)

•	89640 or 89641 with or without external down converter.


Setting up Hardware for Extended Calibration

These are typical hardware setups.

89611A with PSA Option H70

89611A with external down converter

89640/41A with external down converter


Setting up the Source for Extended Calibration

To obtain the greatest accuracy, perform the extended calibration with the source set close to the maximum level for your measurement range. You want to maximize the signal-to-noise ratio for the calibration measurements but avoid distortion. The Extended Calibration Wizard suggests a source level and allows you to change it.

If you are calibrating an 89611 with an Agilent PSA option H70 as a down converter, or an 89640 or 89641 without a down converter, the default source level is equal to the analyzer's range.

If you are using an external down converter, and have properly set up the Utilities > Calibration > Frequency tab, the default source level is the current source output setting. In this case, it is a good idea before calibrating to set the source level to the maximum specified level for your external down converter (but not so high a level as would produce significant distortion).

The maximum source level is 10 dBm. Source levels above this do not produce good calibrations because of non-linearities in the source.


Saving Extended Calibration Data

The Extended Calibration Wizard asks you to specify a file in which to store the data. If you give the name of a file that already exists, the file will be overwritten with the new data. If External IF Calibration is enabled, the default file name is the one currently in use by External IF calibration ; otherwise, the default file name is "ExtendedIf.cal." To change the file name click on the […] button next to the file name, navigate to the directory desired, and either choose an existing file or type in a new name.

The 89600 External IF calibration feature uses the file created by the Wizard. After running the Wizard, you may verify this by going to the VsaVector application and clicking Utilities > Calibration   External Amplitude. The IF calibration checkbox is selected, and the file name you specified appears in the IF Calibration File text box.

You can perform Extended Calibration for different hardware settings and store the results under different file names. Then, when you change between hardware setups, you can go to the IF Calibration File dialog to recall the previous calibration file that was created for that setup. Click the IF calibration […] button to choose a file name.


Canceling Extended Calibration

You can abort calibration before it is finished by clicking Cancel. The analyzer is restored to the state it was in before you ran the Wizard.

After a successful calibration, the Extended Calibration Wizard stores the calibration data in the file you specified and enables External IF calibration. This allows the analyzer to use the calibration data in the file for correcting its time data. The legend "EXT AMP" that appears in the 89600 status bar. You can manually turn External IF calibration on and off by clicking Utilities > Calibration > Amplitude and then clicking the IF Calibration check box.


Extended Calibration Limitations

The calibration source must be able to tune to the center frequency at which calibration is to be done. The source should also be able to provide a full-scale signal at the range which you wish to calibrate. The quality of the calibration measurement depends on a good signal-to-noise ratio.

After calibration, the correction is most accurate as long as the center frequency or range is not changed. The correction is made relative to the center frequency. You may change the measurement span and the correction will be adjusted appropriately to fit the span. The correction (or the part based on the External IF calibration data) doesn't change if you change center frequency or range, but the hardware characteristics for which you are correcting may change and to some extent invalidate the correction. Nevertheless, the correction may still give better accuracy than no correction at all. Here are some considerations that affect the validity of calibration data being used for correction:

•	Does the frequency response change significantly with a change of center frequency (for example, due to a preselection filter before the first mixer of the tuner)?

•	Does the frequency response exhibit hysteresis (i.e., does it change when you tune away from a chosen center frequency and back again)?

•	Does the frequency response change significantly with a change of range (other than by a constant gain or delay over the span)?

•	 Does the frequency response change over time, and how long has it been since the last calibration?

•	Does the frequency response drift with temperature, and has the temperature changed since calibration?

•	Did you replace any of the hardware with equivalent hardware (which nevertheless may have slightly different characteristics?

You must use the above considerations and knowledge of your required measurement performance to determine how often to calibrate. A quick way to determine the accuracy of the correction is to use the flatness macro included with this software to determine the system flatness. To import the flatness macro, click Utilities >  Macros then click Recall. Navigate to the directory in which your VSA software is installed (usually C:\Program Files\Agilent\89600 VSA\) and then to Examples\Macros. Choose flatness.vbs. You can run the macro from the Macros dialog, or from the Macros toolbar (Right-click in the toolbar area and check Macros.)


Extended Calibration for 89611 with PSA Option H70

Extended Cal above 3GHz

For the 89611 system using an Agilent PSA as a down converter, extended calibration is of great benefit when making measurements above 3 GHz. In this range the PSA employs a YIG-tuned preselection filter whose characteristics change with center frequency and with tuning history. For this reason, to achieve the best accuracy you should perform the Extended Calibration each time you change to a new center frequency above 3 GHz. Hysteresis effects may be mitigated by always tuning to either 3 GHz or 26.5 GHz (whichever is farther away) before tuning to your desired center frequency. This may allow you to reuse calibration data taken previously at that center frequency, but the accuracy will be poorer than if you always recalibrate after a center frequency change.

Extended Cal below 3GHz

For frequencies below 3 GHz, the frequency response at a particular center frequency is repeatable. You can calibrate once at a center frequency, store the results in a uniquely named file, and reuse that file for External IF correction whenever you return to that center frequency.

Source Output Power

For all frequencies it is recommended that you do not calibrate on a range above 10 dBm. Source levels above 10 dBm do not produce good calibrations because of non-linearity in the source. Generally, calibration at 0 dBm will apply on any range between -20 and +30 dBm. For ranges below -20 dBm, it is recommended that you recalibrate any time you change ranges.

See Also

Extended Cal with a user-supplied down converter

Extended Cal using the 89640/89641 VSA


Extended Calibration 89611 with User-supplied Down Converter
Extended Calibration for 89611 with User-supplied Down Converter

When you are using the 89611 with an external down converter, you must correctly set up the parameters on the Frequency tab of the Calibration dialog before performing an Extended Calibration. Note especially that the Intermediate Frequency setting is the frequency at which a sine wave signal would appear at the output of the down converter if a sine wave were input at the External Center Frequency. The calibration will fail if these parameters are not accurately set. For the 89611, the IF must be close to (ideally equal to) 70 MHz.

Ranging is also very important for a good calibration measurement. You must find out the expected full-scale input for your down-converter and the expected output at the IF for a full-scale input. You must adjust the range of the 89611 so that the full-scale output from the down converter does not overload the 89611, but not so high that the noise begins to dominate your measurements.

Set the calibration source close to full scale for your converter. Note that the signal level is limited to below 10 dBm for the ESG or PSG regardless of what you enter into the Wizard. Source levels above 10 dBm do not produce good calibrations.

Please refer to the Limitations section above to determine how often and where you should calibrate your system.


Extended Calibration for 89640/89641

If you are not using an external down converter, single cal provides fully specified accuracy, but extended calibration can enhance the accuracy at some frequencies beyond what the internal calibration can do.

When you use an external down converter, the extended calibration can compensate for the down converter's response. The same considerations apply as for the 89611 with user-supplied down converter.


About Printing

Select Print from the file menu to print the trace display area. This prints the whole window except the title bar, menu bar, and status bar. The trace display area and marker readouts (if any) are printed.

Print …

Click Print to open the standard Windows print dialog box. In this dialog box, you can specify which printer to use, which pages to print, and the number of copies to print.

For help on anything in the dialog box, click the question mark in the upper right corner, then click on areas of the dialog box to get help.

Print Setup

Click Print Setup open the standard Windows print setup dialog box. In this dialog box, you can specify which printer to use, paper size and source, and the page orientation.

For help on anything in the dialog box, click the question mark in the upper right corner, then click on areas of the dialog box to get help.

Print Options

You can set up how you want the trace area to print. All your selections are remembered while 89600 VSA is running. When you stop and restart the 89600 application, all selections reset to their default values.

•	Force white background: If this is selected, the background will be white. Very light colors will print black so that you can see them.

If Force white background is cleared, the trace area is printed using colors exactly as they appear on the screen.

Hint

Large areas of black do not print well on inkjet-style printers. If your printer is an inkjet-type, your print quality will be better if you select Force white background.

•	Limit to top half of page: If Limit to top half of page is selected, the trace area is printed in the top half of the page. This applies for both portrait and landscape page formats.

If Limit to top half of page is cleared, the trace area is printed on the whole page.

•	Stretch to fit page: If Stretch to fit page is selected, the trace area is expanded both horizontally and vertically to fill the whole page or half-page. The font size does not change.

If Stretch to fit page is cleared, the trace area is expanded until it reaches the maximum width or height of the specified area (half page or full page), whichever happens first. The image maintains the same aspect ratio as displayed on the monitor.