Oset from Carrier Most Likely Fault
60 kHz Grounds, connections and shielding,
A16, A17, A18
120 kHz A16, A17, A18
20 or 40 kHz A3, A6 shielding/ltering
Random Low Frequency Fan (B1)
10 or 20 MHz Routing of cables to and from A7.
These problems are very dicult to isolate, and require
patience. Often, the quickest and most economical way
to isolate a problem is to substitute modules.
After taking action, go to the Troubleshooting Foldout,
block 1 (located just prior to the \Special Cases" tab).
ILT.2640
Poor grounds or shielding problems in either the
environment or the measurement system can produce
what looks like a failure in phase noise measurements
.
Another common source of phase noise is physical
vibration. When you are sure that the measurements
accurately reect a failure, refer to the following graph.
Locate the failed frequency on the graph and go to the
paragraph shown for that frequency. Note, if your failure
is between 100 Hz and 1 kHz, check frequencies above
and below the failure. If the frequencies below 100 Hz
are failing or are close to failing, go to A7.9000. If the
frequencies above 1 kHz are failing or are close to failing,
go to A6.9000. In the synthesizer, phase noise is usually
concentrated at one of three carrier osets.Failures
of phase noise at these osets have fairly predictable
causes. Before you change a module, check the phase
noise measurement system.
Agilent 8360 Instrument Level Troubleshooting 1a-45
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