Keysight N9038A, Service Manual, Page: 234 / 745

234 Keysight N9038A MXE Service Guide
RF Downconverter Section
RF Downconverter Section Troubleshooting
before any other troubleshooting is performed. The most probable causes for
this type of a problem would be that the A11 RF Switch / High Band Preamp
assembly itself is defective.
Signal Path Verification
There are three different signal paths through the A11 RF Switch / High Band
Preamp, each of which will be verified in this section. The frequency range of
each signal path and the expected signal loss or gain for each path is listed in
Table 6-6 and Table 6-7 .
Since the instrument communicates with the A11 RF Switch / High Band Preamp assembly
through the A15 Front End Control assembly, be sure that the A15 Front End Control assembly is
initializing properly before replacing an A11 RF Switch / High Band Switch assembly for not
initializing properly.
Table 6-6 A11 RF Switch / High Band Preamp Signal Paths - Option 508 & 526
Signal Path Frequency Range Loss / Gain
Value Condition
Low Band 20 Hz to 3.6 GHz − 1.2 dB 20 Hz to 2.5 GHz
− 1.4 dB 2.5 GHz to 3.6 GHz
High Band Thru
a
3.6 GHz to 26.5 GHz − 8.0 dB 3.6 GHz to 22 GHz
− 12.0 dB 22 GHz to 26.5 GHz
High Band Preamp
a 3.6 GHz to 26.5 GHz
+30.0 dB
b
3.6 GHz to 26.5 GHz
a. Option 508 and 526 only
b. Relative to thru path
Table 6-7 A11 RF Switch / High Band Preamp Signal Paths - Option 544
Signal Path Frequency Range Loss / Gain
Value Condition
Low Band 20 Hz to 3.6 GHz
−
1.0 dB 20 Hz to 0.5 GHz
−
1.6 dB 0.5 GHz to 3.6 GHz
High Band Thru 3.6 GHz to 44.0 GHz
−
7.0 dB 3.6 GHz to 15 GHz
−
5.0 dB 15 GHz to 35 GHz
−
7.0 dB 35 GHz to 44 GHz