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Further Isolating RF Failures
NOTE
Test Sets with firmware revision A.04.5X and above operate only at RF
frequencies from 800 to 1000 MHz and 1700 to 2000 MHz. A text only error
message "Input value out of range" , will be displayed if invalid
frequencies are set.
Isolating failures in the RF assemblies of the Test Set can be difficult. One problem
occurs when the diagnostics use the built-in RF analyzer to test the built-in RF
source, and vice versa. This is necessary to make the diagnostics self-contained,
that is, they run without external equipment.
Some general-purpose, RF test equipment will be needed:
• RF signal generator
• RF modulation analyzer or spectrum analyzer.
Isolating the RF Analyzer
The RF Analyzer function uses the following assemblies. Refer to
the block diagrams in
• Downconverter
• Receiver
• Receiver Synthesizer
• Spectrum Analyzer (optional)
Figure 2-19
Isolating the RF Analyzer
ANT
IN
RF
IN/OUT
DUPLEX
OUT
chapter 8, "Block
Input
OPP*
Attenuator
Power
Detector
Splitter
RPP†
Output
Attenuator
RF I/O
FROM RF SOURCE
Manual Troubleshooting Procedures
Diagrams".
Down
Demod
Receiver &
Conversion
(FM, AM, SSB)
IF
Receiver
Synthesizer
LO/IF
RF Analyzer
Reference
*OPP = Over Power Protection
†RPP = Reverse Power Protection
Troubleshooting
figure 2-19
and
Spectrum
Analyzer
(optional)
75
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Troubleshooting
