Service Guide E8361-90001 3-33
PNA Series Microwave Network Analyzers Tests and Adjustments
E8361A Performance Tests (Agilent N2721A Software Package)
System Crosstalk Test
Function of the Test: To measure the level of signal leakage between the analyzer’s test
ports.
Specification Tested: Test Port Input–Crosstalk
Equipment Used: A calibration kit and a test cable.
Description of the Test:
1. The analyzer is tested in both directions at various frequency segments.
2. The analyzer sweep is set for the desired frequency and number of points at a 10 Hz IF
bandwidth. The power level is set to the lesser of either the maximum specified power
level for the driving port or the maximum input power level for the receiving port.
3. A test cable is connected between the driving and receiving ports.
4. The analyzer is set for a ratioed through measurement (S21 for example) with log
magnitude display and a sweep is taken and stored to memory (MEM).
5. The trace is set to data divided by memory (DATA/MEM).
6. The test cable is removed and shorts are placed on both ports.
7. The average of 16 sweeps is taken.
8. The resultant log magnitude trace represents the system crosstalk in dB for the
frequency range or segment tested.
If the Analyzer Fails this Test:
• A failure of this test usually indicates one of the following:
• a loose cable connection
• degradation of signal isolation in the receivers
• degradation of signal isolation on the A35 receiver motherboard
• Remove the covers from the analyzer and tighten all test cable connections and tighten
all screws on the receivers and repeat this test. Refer to “Removing and Replacing the
A31, A32, A33, and A34 Receiver Modules and LO Reject Filter Board” on page 7-50 for
instructions on how to remove the covers and for illustrations of the cable and screw
locations.
• If the analyzer still fails this test, replace the receiver associated with the port that is
failing and repeat this test. Refer to “Removing and Replacing the A31, A32, A33, and
A34 Receiver Modules and LO Reject Filter Board” on page 7-50.
• If the analyzer still fails this test, replace the A35 receiver motherboard and repeat this
test. Refer to “Removing and Replacing the A35 Receiver Motherboard” on page 7-52.
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