Keysight N9923A, User Manual, Page: 88 / 276

88 Keysight N9923-90001 User’s Guide
CAT (Cable and Antenna Test) Mode
2-Port Insertion Loss Measurements
14. Use Averaging to remove random noise from high-loss measurements.
Press BW 2 then Average .
The displayed trace shows the Cable Loss values in one direction through the
cable. A Return Loss measurement would show the loss for both down the
cable and back. Therefore, a Cable Loss measurement is the same as a Return
Loss measurement divided by 2.
The average Cable Loss across the specified frequency range is shown on the
screen below the graticules.
2-Port Insertion Loss Measurements
A 2-port Insertion Loss measurement is used to measure the loss through a
DUT (device under test) – or cable – over a specified frequency range. 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, either directly or indirectly using the cable used in the
normalization cal.
‘Insertion’ loss simply means
loss
through a device, usually expressed in dB. It
is exactly the same measurement as “S21 Transmission” in NA Mode.
2-port Insertion Loss measurements are generally more accurate than 1-port
Cable Loss measurements.
How to make a 2-port Insertion Loss Measurement
— Press
Mode
then
CAT
.
— Then
More
then
Insertion Loss (2-Port)
.
— Press
Freq/Dist
and enter
Start
and
Stop
frequency values of the
measurement.
— Press
Sweep 3
, then select a
Resolution
setting.
— Press
Cal 5 , then perform a calibration. Learn more on “How to Perform a
Calibration” on page 104
.
— Connect the DUT and view the insertion loss measurement results.
When measuring very long lengths of cable, it may be necessary to increase
the sweep time. Learn how in
“Sweep Time” on page 82
. Learn why in the
Supplemental Online Help
:
http://na.support.keysight.com/fieldfox/help/SupHelp/FieldFox.htm