Accuracy Calculator for Frequency Counters

The following assumptions have been made:

• Total Measurement Error = Systematic Uncertainty ± s * RMS Resolution Measurement Error has been computed to within 2-sigma confidence (ie s = 2).

• A 1 year Time Base Error, assuming the instrument is operating within the specified temperature range and a 1 year specifications for the aging rate (ie Time Base Error = Temperature Stability + Daily Aging Rage * 30 days + Monthly Aging Rate * 11 Months). A lower time base error can be used for the time leading up to the calibration and just after calibration. See Tips for making more accurate measurements with a frequency counter.

• The formulas for Systematic Uncertainty and RMS Resolution are given in the manuals and data sheet. The typical values for tres, tacc, and tjitter provided in the manuals and data sheet have been used in this calculator.

• It has been assumed that the trigger error is negligible compared to the total measurement error. If the input signal is noisy, the trigger points that define the beginning and end of a measurement may be advanced or delayed. The resulting timing uncertainty is a function of the slew rate of the signal and the amplitude of spurious noise spikes.

• It is assumed the trigger is set to auto trigger at a 50% level.

• It is assumed the instrument is calibrated and operated in accordance to good metrology standards.

Please press the Calculate button!