Keysight N5221A Service Manual page 44

Tests and Adjustments
Preliminary Checks
Cable Magnitude and Phase Stability Check
1. With the test port cable still connected to Port 1, connect a short to the other end of the cable.
2. Press UTILITY Preset
3. Press TRACE/CHANNEL
and then click OK.
4. Press RESPONSE Format
5. Press RESPONSE Avg
softkey to toggle it ON.
The Averaging Factor box will appear directly above the display. In the Averaging Factor box, type 50 or
click the arrows to select 50, and then press ENTRY
6. To provide a good reference, hold the test cable in a straight line perpendicular to the front panel of the
network analyzer.
7. Press RESPONSE
Avg
8. Wait for the analyzer to average the measurement 50 times (approximately two seconds).
9. To normalize the data trace: press MARKER/ANALYSIS
, then
Data Math Data/Memory
10. Slowly make a 180 degree bend in the middle of the cable and hold it in that position.
11. For each trace: press RESPONSE
The Scale Per Division box will appear directly above the display. Set the Scale Per Division for
optimum viewing as shown in
12. Place a marker on the largest deflection that goes above the reference line and is within the cable's
specified frequency range. For a typical response of cable magnitude and phase stability, see
13. Place a marker on the largest deflection that goes below the reference line and is within the cable's
specified frequency range.
In this S measurement, the displayed trace results from energy being propagated down the cable and
11
reflected back from the short. Therefore, the measured deflection value must be divided in half to reach
the correct value.
3-16
.
Traces , then New Trace...
, then Phase , then ENTRY
Average ON/off
. Verify that
, then
Averaging Restart
, then ENTRY
Scale , then
Figure 3-6.
PNA Series Microwave Network Analyzers
. In the New Trace dialog box, click the S11 box,
Enter .
is ON. If not, press the
.
Enter
.
Memory , then
.
Enter
.
Scale
N5221A/22A
Average on/OFF
, then
Data Trace
Figure
Service Guide N5222-90001
3-6.