Keysight N9923A FieldFox User Manual page 107

1-Port Cable Trimming Measurements
A 1-Port Cable Trimming measurement is used in a cable fabrication procedure to
validate proper electrical length.
How to make a 1-Port Cable Trimming Measurement
1. Press Mode then
2. Press Freq/Dist and enter the frequency for the measurement.
3. Press Meas Setup 4 then
4. Calibrate the FieldFox: (Learn more about VVM calibration on page 106.)
5. To ensure that the FieldFox is properly calibrated, perform the following optional
NOTE This measurement verification procedure is suitable for low frequency
measurements. However, for high frequency measurements, a more sophisticated
procedure is required.
6. Attach the shortest cable to the FieldFox PORT 1 connector. This cable is the
7. Press Meas Setup 4 then press Zero.
8. Remove the reference cable from the FieldFox PORT 1 connector.
9. Connect an unterminated, longer cable to the FieldFox PORT 1 connector.
10. Observe the displayed phase difference between the reference cable and the
VVM (Vector Voltmeter) Mode
FieldFox Block Diagram
VVM
If using an adapter to connect the cables to the FieldFox, press Cal 5 then
o
select either
QuickCal
prompts. During calibration, the measurement (S-parameter) is referred to as
S11.
If connecting the cables directly to the FieldFox test port, CalReady is very
o
accurate.
Measurement Verification procedure.
a. Connect a short standard to the PORT 1 calibration plane (the location
where the calibration was performed).
b. Press Meas Setup 4 and press Zero.
c. Connect the open standard to the FieldFox PORT 1 connector.
d. Confirm that magnitude measurement is less than –0.1 dB and that the
phase value reads 180 degrees.
reference cable. Leave the end of the reference cable open (unterminated).
attached cable.
 The R receiver measures incident signal (green line)
out of the source.
 The A receiver measures reflected signal (red line)
from the end of the DUT (black line).
 In VVM mode, the display ALWAYS shows ratioed
(A/R) measurements which is the electrical length of
the DUT.
then
1-Port Cable Trimming.
Zero OFF.
or Cal. Follow the FieldFox calibration
Mechanical
107