Keysight N9038A, Руководство по обслуживанию

Страница: 238 / 745

238 Keysight N9038A MXE Service Guide
RF Downconverter Section
RF Downconverter Section Troubleshooting
Figure 6-9 A11 RF Switch / High Band Preamp - Low Band Signal Path
If the signal is:
— The correct level
Proceed to the next step
— Lower than expected
Switch the A11 RF Switch / High Band Preamp assembly
to the high band signal path by pressing FREQ , 6 GHz .
If the signal level decreases further, the most probable
cause is a bad A11 RF Switch / High Band Switch
assembly.
If the signal does not decrease any further, verify that the
switch control lines from the A15 Front End Control
assembly are working properly. Refer to Chapter 8, “Front
End Control.” for instructions on how to verify the control
lines.
13. Tune the signal generator and spectrum analyzer to any other frequency
up to 3.6 GHz and verify that the loss through the low band signal path
remains within a few dB of the values outlined in Table 6-6 or Table 6-7 .
The isolation from the input port to the low band output port of the A11 RF Switch / High Band
Preamp when the input is switched to either of the high band paths is less than 20 dB. Because
of this, if the signal path appears to be less than 20 dB too low it could be that the switch control
lines from the A15 Front End Control assembly are at fault.