The Calibration Unit is delivered with factory characterization data which ensure an accurate calibration for all standard applications. For specific modifications of the test setup, e.g. the connection of additional adapters to a calibration unit, a modified set of characterization data (suitable for the cal unit with adapters) may be desirable. The analyzer provides a Characterization Wizard for performing a guided characterization of (modified) R&S calibration units. The acquired characterization data is stored to a characterization file, so that it can be used for automatic calibration whenever needed.
A cal unit characterization can be performed in a frequency sweep. The network analyzer must be properly calibrated for the test setup, with the reference plane at the input ports of the (modified) cal unit to be characterized. The procedure involves the following steps:
Perform a calibration of your network analyzer, using the test setup and calibration type you wish to perform with your (modified) calibration unit (see description of the Characterization Wizard).
Connect the modified calibration unit to the reference plane (see Connection and Installation)
Click Channel – Calibration – Characterize Cal Unit to access the Characterize Cal Unit dialog and start the wizard.
Step through the wizard, following the instructions in the dialogs.
The Characterize Cal Unit dialog displays the properties of the connected cal units, provides control elements for characterization file management, and starts the characterization wizard.
In the dialog, you can:
Select a cal unit from the list of connected units (Select Cal Unit, relevant if several units are connected). Refresh Representation initiates a new hardware detection and updates the list.
Set a password to prevent the characterization dialog and the Start Characterization wizard from unauthorized operation and access. Set Password opens a dialog to enter the password and activate password protection at the next time the Characterize Cal Unit is opened. Enter an empty string (no password) to deactivate password protection.
View the list of available characterization data sets and their Properties.
Select a characterization from the list. You can set this characterization active for subsequent calibration processes using the selected cal unit (Set Active), Export the data to a *.s1p Touchstone file (e.g. for comparison with older characterization data or characterization data with/without connected adapters), or Delete the data. Note that Export... will initiate an export of all characterization data to different *.s1p files, each containing the name of the characterization in its file name. Press Save to transfer the active characterization data set to the selected cal unit and complete the characterization procedure.
Start the characterization wizard (Start Characterization).
A cal unit characterization can be performed in a frequency sweep. Start Characterization is unavailable while a power, CW Mode, or time sweep is active. The analyzer always uses a fixed source power of –10 dBm to acquire the characterization data.
Remote control:
[SENSe<Ch>:]CORRection:COLLect:AUTO [SENSe<Ch>:]CORRection:COLLect:AUTO:PORTs [SENSe<Ch>:]CORRection:COLLect:AUTO:PORTs:CONNection?
The Characterization Wizard consists of a series of dialogs which perform a new characterization of the R&S calibration unit. It is opened from the Characterize Cal Unit dialog. Characterization involves the following steps:
Select the calibration type
The calibration unit supports different calibration types. Depending on the desired calibration type, a simpler or more complicated characterization procedure is required. The NWA calibration that you have to perform before connecting the calibration unit also depends on the desired calibration type:
If Full One Port and Full Two Port calibrations are needed, a simple characterization procedure involving only one-port measurements is sufficient. The calibrated ports are connected one after another. A Full One Port or Full Two Port calibration of the analyzer at all ports used for the characterization is recommended.
If a One Path Two Port calibration is needed in addition, the characterization procedure also involves two-port measurements. The calibrated ports are all connected at the same time. A Full N Port calibration of the analyzer (for N calibrated ports), for different connector types and adapters preferably UOSM, is required.
Select the characterized cal unit ports
Perform the necessary characterization sweeps, depending the selected calibration type (step 1)
Save the characterization data
Characterization data are saved in ASCII format with a specified file name and comment. The default file extension is *.calkit; the files are written to a subdirectory of C:\Rohde&Schwarz\Nwa\Calibration (or any other specified directory). The network analyzer automatically creates a file header containing the following information:
Current date and time
Characterized ports, together with their connector types and gender
Operating temperature of the calibration unit
Sweep parameters: sweep type, number of points, frequency range
The created characterization data set is automatically transferred to the active cal unit; the *.calkit file name appears in the list of available Characterization Data.