Pll Range Alarm; Pll Jitter Alarm - Symmetricom TimeSource 2700 Manual

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PLL Range Alarm

A range event should not occur in a normally operating system
after the first minute from a cold power-up. The PLL range event is
processed through a leaky-bucket alarm manager, to control
escalation to a minor alarm. The leaky-bucket manager is set so
that a single isolated event will not escalate to an alarm. The
nominal time to escalate to an alarm is 750 ms. The maximum
time to retire an alarm is 40 seconds.
Maintenance action required - If the system is in warm-up, no
action is required. If a PLL range alarm occurs without
simultaneous input alarm activity, the VCXO may be at the end of
its pull-in range, and the shelf requires immediate replacement. If
the range PLL alarm occurs with some inputs operating alarm
free, there is no immediate problem, but the shelf will soon require
replacement.

PLL Jitter Alarm

If the jitter level exceeds 10 counts at 10 bits for nominally
100 ms, a PLL jitter alarm is reported.
Maintenance action required - Replace the shelf.
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Troubleshooting
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