2-Port Transmission Measurement - Keysight N9912A User Manual

14. Confirm that magnitude measurement is less than –0.1 dB and the phase is
Perform Cable Trimming:
1. Attach the shortest cable to the FieldFox RF OUT connector. This cable is the
2. Press Meas Setup 4 then press Zero.
3. Remove the reference cable from the FieldFox RF OUT connector.
4. Connect an unterminated, longer cable to the FieldFox RF OUT connector.
5. Observe the displayed phase difference between the reference cable and the
6. Carefully trim the cable until the phase shift reads zero. The attached cable's
7. Repeat steps 4 through 6 for the remaining cables to be trimmed.
2-Port Transmission Measurements
A 2-Port Transmission measurement is used for measuring electrical length,
insertion loss, gain, or isolation of a device. The FieldFox signal source is transmitted
out the RF OUT connector, through the DUT, and into the RF IN connector. Both
ends of the DUT must be connected to the FieldFox.
NOTE Only Magnitude, NOT Phase, is displayed.
In the following image, the gain of an amplifier is being measured.
2-Port Transmission measurement of an amplifier
How to make a 2-Port Transmission Measurement
1. Press Mode then
2. Press Freq/Dist and enter the measurement frequency.
3. Connect the RF Out and RF In test port cables to form a Thru connection. If an
4. Press Meas Setup 4 then Zero.
5. Connect the DUT as in the diagram above.
6. The displayed magnitude value is the gain of the amplifier. To measure isolation
146
within .1 degrees of the value from step 9.
reference cable. Leave the end of the reference cable open (unterminated).
attached cable.
electrical length is now matched to the reference cable.
VVM
adapter is needed to make the connection, the measurement results will be in
error by the amount of loss in that adapter.
of the amplifier, reverse the connection to the amplifier (RF Out to the amplifier
output).
then
2-Port Transmission.
FieldFox User's Guide