Keysight NFA Series Noise Figure Analyzers Service Guide 207
RF Section Troubleshooting (N8976B)
Troubleshooting
If the power level is not within tolerance, press FREQ, Zero Span, AMPTD,
Attenuation, Mech Atten, 10 dB.
IMPORTANT Turn off auto align by pressing System, Alignments, Auto Align, Auto Align,
Off.
Disconnect the W36 cable from A13J7 on the Front End Assembly IF Out.
See Figure 5-1.
Connect A13J7 output to a functioning spectrum analyzer and verify the
322.5 MHz intermediate frequency is measuring −22 dBm ± 3 dB using the
same analyzer settings as in Figure 5-2.
Figure 5-2 322.5 MHz Intermediate Frequency
If this power level is correct the signal path from the A9 50 MHz Reference
signal input port to A13J7, IF Output is operating correctly using a 50 MHz
input calibrator signal. Reconnect the 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 an external source to verify performance.
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