Technical data

Chapter 7 7-31
Source Troubleshooting
Source Group Troubleshooting Appendix
Phase Lock Diagnostic Routines
Perform the following steps to determine at what frequencies and bands the phase lock
problem occurs.
1. Press to
switch off the automatic phase-locked loop. Normally, when the phase-locked loop
detects lock problems, it automatically aborts the sweep and attempts to recalibrate the
pretune cycle. Switching off PLL AUTO defeats this routine.
2. Press to switch on the phase-locked loop diagnostic service mode. In
this mode, the phase lock cycle and subsweep number are displayed on the analyzer
display. (See “Service Modes Menu” on page 10-16 for more information.)
3. Press to pause the phase lock sequence and determine where the source
is trying to tune when lock is lost.
Refer to “Source Theory Overview” on page 12-14 for additional information regarding
band related problems. Then use the procedures in this chapter to check source functions
at specific frequencies.
Preset System
SERVICE MENU SERVICE MODES PLL AUTO OFF
PLL DIAG ON
PLL PAUSE