Agilent Technologies N5241A, Service Manual

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3-16 Service Guide N5242-90001
Tests and Adjustments PNA Series Microwave Network Analyzers
Preliminary Checks N5241A/42A
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 .
3. Press TRACE/CHANNEL , then . In the New Trace dialog box,
click the S11 box, and then click OK .
4. Press RESPONSE , then , then ENTRY .
5. Press RESPONSE . Verify that is ON . If not, press the
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 , then .
8. Wait for the analyzer to average the measurement 50 times (approximately two
seconds).
9. To normalize the data trace: press MARKER/ANALYSIS , then ,
then , then , then ENTRY .
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 , then .
The Scale Per Division box will appear directly above the display. Set the Scale Per
Division for optimum viewing as shown in Figure 3-6 .
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
Figure 3-6 .
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
11
measurement, the displayed trace results from energy being propagated
down the cable and reflected back from the short. Therefore, the measured deflection
value must be divided in half to reach the correct value.
Preset
Traces New Trace ...
Format Phase Enter
Avg
Average ON/off
Average on/OFF
Enter
Avg Averaging Restart
Memory Data Trace
Data Math Data/Memory
Enter
Scale Scale