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3738A IF Path Description and Checks:
As shown in Figure D-3, there are four separate IF paths in the 3738A.
Each path is composed of an ampifier (gain is approximately 13 dB)
and a GaAs switch. The signal through these paths is fixed at
270 MHz, which is the down-converted signal from the 3742A mod-
ules.
Regardless of sweep direction, the GaAs switches and the IF amplifi-
ers are biased ON (pass RF) when the system frequency is above
65 GHz, and are OFF when the system frequency is below 65 GHz.
Correct bias voltages at TP3, TP9, and TP10 are shown on the chart
above.
System Dynamic Range Problem:
Ensure that both MG369XX synthesizers have Option 3 installed and
that the IF Power Level tests pass.
RF Overload Messages Appear:
This may be caused by the 374XA modules being moved from one
ME7808B/C system to another due to normal variations in amplifier
gains between different systems. To solve the problem, install a 3 dB
pad between the 37XXXD rear panel and the appropriate RF cable (a1,
a2, b1, b2).
APPENDIX D
TROUBLESHOOTING
37XXXD MM
D-27/D-28
Содержание 37 D Series
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Страница 14: ...1 2 37XXXD MM Figure 1 1 Series 37XXXD Vector Network Analyzer System...
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Страница 35: ...REPLACEABLE PARTS PARTS ORDERING INFORMATION 37XXXD MM 2 9 2 10 Figure 2 2 Signal Source Parts Location Diagram...
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Страница 143: ...REMOVE AND REPLACE SIGNAL SOURCE MODULES 37XXXD MM 8 23 Figure 8 11 Signal Source Module Assemblies Removal Details...
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Страница 160: ...D 4 37XXXD MM ME7808 BLOCK DIAGRAM ME7808 BROADBAND SYSTEM MAINTENANCE Figure D 1 ME7808B C Block Diagram...
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