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172 Keysight N9923-90001 User’s Guide
VVM (Vector Voltmeter) Mode - Option 308
A/B and B/A Measurements
A/B and B/A Measurements
These measurements allow you to use the FieldFox A and B receivers, along
with an external source, to make ratioed measurements.
The image below shows a typical configuration for a B/A magnitude and phase
measurement of a 2-port DUT. This DUT can be an antenna / probe setup.
Using network analyzer terms, the image shows the A receiver as the reference
receiver which measures the signal that is applied to the DUT. The B receiver is
the test port receiver which measures the DUT response.
Figure 11-4 B/A Transmission measurement with external source
Procedure
1. Connect the external source’s frequency reference output to the FieldFox
Freq Ref IN on the top panel. If you are unable to use a common frequency
reference, then increase the IFBW to ensure you are measuring the peak of
the correct signal. After locating and tuning to the signal, you may be able
to lower the IFBW to reduce noise.
2. On the FieldFox, select System 7 , then System Configuration , then
Frequency Ref , then Freq Ref Source then Ext .
3. Press Mode , then VVM , then B/A or A/B
4. For highest accuracy, set the FieldFox output power to Low. Press Meas
Setup 4 , then More , then Output Power Low .
5. To calibrate, replace the DUT with a THRU connection, preferably by
connecting together the two Power Splitters (shown in green in the
graphic above). For low frequency measurements, TEEs can be used.
6. Press Meas Setup 4 , then Zero .
7. Connect the DUT and measure.
These measurements require the “Full 2-port S-parameters” option.