Provisioning The Operating Mode Of The Clock Module - Symmetricom TSG-3800 Series User Manual

Locked Mode
In Locked mode, the tau increments until the Clock Module is phase locked and final
tau is achieved, which maintains the output frequency with respect to the input
reference. The processor continues to measure the phase of each input. It adjusts
the control value based on phase changes of the selected reference.
Holdover Mode
When an acceptable input reference is not available, the TSG-3800 automatically
enters Holdover mode. In Holdover, all outputs continue to be present without
interruption, but the TSG-3800 stops updating the control value to the oscillator and
uses the average control value of the last 24 hours. Changes in output frequency
are now due to aging and environmental variations only.
When the TSG-3800 leaves Holdover, it compares the phase of the Clock modules
to the reference. If the two phases agree, the TSG-3800 resumes operation in the
phase-locked loop (Locked mode) using the pre-holdover phase setting. If the
phase differs significantly (>110 ns), the TSG-3800 enters Acquire mode before
returning to Locked mode.
Holdover mode may also be entered into manually. When entered into manually, the
Clock module stays in Holdover until the operator changes operating modes.

Provisioning the Operating Mode of the Clock Module

The operator can check the type of Clock modules installed in the shelf, its
operating state and loop time constant. To display this information, type:
then press Enter
CLK
A typical display is:
TSG->CLK
CLK A, Stratum 2E Rubidium
Status
Reference
CV: -168
WarmUp Time:
900
Clk B, Stratum 2E DDS
Status: OK
CV: -1510
WarmUp Time:
1800
TSG->
12778474-002-2 Revision F – March 2004
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Mode: Acquire Tau: 592
%CV: 49.21 Freq Off:
3.73e-10
Min Tau: 500 Final Tau: 2500
Mode: Acquire Tau: 423
%CV: 49.38 Freq Off:
3.35e-09
Min Tau: 100 Final Tau: 1500 Max Tau:
Operating the TSG-3800
Provisioning the Clock Modules
Sigma
3.2e-14
Range:+5.76e
-0 8
Max Tau:
10000
Sigma:
8.96e-13
Range:
+-8.95e-0
5000
TSG-3800 User's Guide 97