Keysight N9038A, Service Manual

Page: 183 / 745

Keysight N9038A MXE Service Guide 183
RF Preselector Section
RF Preselector Section Troubleshooting
16. Tune the spectrum analyzer to a start frequency of 1 MHz and a stop
frequency of 6 GHz.
17. Tune the instrument to a frequency of 1 GHz with a span of 0 Hz by
pressing FREQ , 1 GHz , and SPAN , Zero Span .
18. Verify that the signal level on the spectrum analyzer is at
−
20 dBm (±2 dB),
as shown in Figure 5-10 , allowing for any additional test cable loss.
If the signal level is incorrect the most likely cause of the problem is the
A21 RF Preselector Input assembly itself.
Figure 5-10 A21 RF Preselector Input Assembly - Radiated Band Pre-Filter
Pre-Filter Shape Verification - Radiated Band
19. Placing one of the active traces on the spectrum analyzer into its Max
Hold function.
20. Slowly vary the frequency of the signal generator between 1 MHz and 6
GHz to draw out the shape of the radiated band pre-filter on the spectrum
analyzer display, as shown in Figure 5-10 .
21. Verify that the filter shape on the spectrum analyzer display is similar to
that shown in Figure 5-10 .
If the filter shape is incorrect the most likely cause of the problem is the
A21 RF Preselector Input assembly itself.