144 Keysight NFA Series Noise Figure Analyzers Service Guide
RF Section Troubleshooting (N8973B, 74B, 75B Analyzers)
Troubleshooting
Connect A13J7 output to a functioning spectrum analyzer and verify the
322.5 MHz intermediate frequency is measuring −28.5 ± 3 dB using the same
analyzer settings as in Figure 4-3.
Figure 4-3 322.5 MHz Intermediate Frequency
If this power level is correct the RF assembly from the A9 50 MHz Reference
signal input port to A13J7, 322.5 MHz I.F. Output is operating correctly using a
50 MHz input calibrator signal. Reconnect the W15 or W36 cable to A13J7.
Flatness issues or power level problems at other input frequencies below
3600 MHz may exist. This type of problem can be diagnosed using the
suspect RF input frequency.
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