2-Port Insertion Loss Measurements - Keysight N9912A User Manual

7. Press Cal 5, then
8. Follow the prompts to perform calibration at the end of the jumper cable or
9. Connect the cable to be tested.
NOTE Low-level standing waves (also known as 'ripple') which may be visible in reflection
measurements, can hide the actual loss of the cable. Steps 10 through 13 can
minimize the ripple. Perform the measurement with and without steps 10 through 13
and choose the method with the least amount of ripple.
10. Connect a LOAD at the end of the cable to be tested. This limits the reflections
11. Press Trace 6 then
12. Remove the LOAD and leave the end of the cable to be tested open.
13. Press
14. Use Averaging to remove random noise from high-loss measurements. Press
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, available with option 110, 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.
NOTE A Normalization Cal is REQUIRED for making accurate 2-port CAT or NA
measurements. Learn how on page 63.
For highest accuracy, when measuring the DUT also attach any cable or adapter that
was used in the normalization cal.
How to make a 2-port Insertion Loss Measurement
1. Press Mode then CAT.
2. Then
3. Press Freq/Dist and enter
4. Press Sweep 3, then select a
5. Press Cal 5, then press Normalization. Perform normalization as explained on
28
QuickCal
adapter. Learn more about Calibration on page 61.
to faults that are located in the cable under test.
Data->Mem
then
Data –
Data Math
These minor imperfections in the cable should not be considered in the Cable
Loss measurement.
BW 2 then Average.
then
More Insertion Loss (2-Port)
measurement.
page 63.
or OSL.
to store the trace into Memory.
Mem. The ripple in the measurement is removed.
.
and frequency values of the
Start Stop
setting.
Resolution
FieldFox User's Guide