Keysight N5221A Service Manual page 46

Tests and Adjustments
Preliminary Checks
Cable Connector Repeatability Check
NOTE The connector repeatability measurement should be done at the test port as well as at the
end of the test port cable.
1. With the test port cable still connected to Port 1, connect a broadband load to the other end of the cable.
2. Press UTILITY
Preset
3. Press RESPONSE Avg
softkey to toggle it ON.
The Averaging Factor box will appear directly above the display. In the Averaging Factor box, type 100 or
click the arrows to select 100, and then press ENTRY
4. Wait for the analyzer to average the measurement 100 times (approximately five seconds).
5. To normalize the data trace: press MARKER/ANALYSIS
Data Math , then Data/Memory
6. To adjust the display scale:
a. Press RESPONSE
The Scale Per Division box will appear directly above the display. Set the Scale Per Division for 0.5
dB. Press ENTRY
b. Press
Reference Level
The Reference Level box will appear directly above the display. Set the Reference Level for 0 dB.
Press ENTRY
Enter
7. Disconnect and then reconnect the cable to the test port. Tighten the connection to the specified torque
for the connector type.
8. Press RESPONSE
Avg
9. Look at the trace for spikes or modes.
10. To re-normalize the data trace of the reconnected cable: press MARKER/ANALYSIS
, then ENTRY
Data->Memory
11. Repeat steps 7 through 9 at least three times to look for modes. Modes appear when a harmonic of the
source fundamental frequency is able to propagate through the cable or connector. It is helpful to print a
plot of the trace each time to compare several connections. If any mode appears each time the cable is
connected and reconnected, measurement integrity will be affected.
For a typical response of cable connector repeatability, see
12. For the Port 2, 3, and 4 Check, connect the cable (with the load attached) to the respective port and
repeat steps 2 through 11.
3-18
.
Average ON/off
. Verify that
, then ENTRY
, then .
Scale Scale
.
Enter
.
.
, then
Averaging Restart
.
Enter
PNA Series Microwave Network Analyzers
is ON. If not, press the
Enter .
, then
Memory Data Trace
Enter .
.
Figure 3-7.
N5221A/22A
Average on/OFF
, then
Memory , then
Service Guide N5222-90001