Keysight N9923-90001 User’s Guide 169VVM (Vector Voltmeter) Mode - Option 3081-Port Cable Trimming Measurements1-Port Cable Trimming MeasurementsA 1-Port Cable Trimming measurement is used in a cable fabrication procedureto validate proper electrical length.How to make a 1-Port Cable Trimming Measurement1. Press Mode then VVM then 1-Port Cable Trimming.2. Press Freq/Dist then enter the frequency for the measurement.3. Press Meas Setup 4 then Zero OFF.4. Optionally calibrate the FieldFox. Learn more about VVM calibration in“VVM Calibration” on page 167.— If using an adapter to connect the cables to the FieldFox, press Cal5 then select either QuickCal or Mechanical Cal. Follow the FieldFoxcalibration prompts. During calibration, the measurement(S-parameter) is referred to as S11.— If connecting the cables directly to the FieldFox test port, CalReadyis very accurate.5. To ensure that the calibration is adequate, perform the following optionalMeasurement Verification procedure.a. Connect a short standard to PORT 1 where cables to be trimmedwill be connected.b. Press Meas Setup 4 and press Zero.c. Remove the short standard and connect the open standard.d. Confirm that magnitude measurement is less than –0.1 dB and thatthe phase value reads 180° degrees.— The R receiver measures incidentsignal (green line) out of the source.— The A receiver measures reflectedsignal (red line) from the end of theDUT (black line).— In VVM mode, the display ALWAYSshows ratioed (A/R) measurementswhich is the electrical length of theDUT.This measurement verification procedure is suitable for low frequencymeasurements. However, for high frequency measurements, a moresophisticated procedure is required.
