Forcing A Clock Module Out Of Holdover; Establishing Nominal Phase Setting; Frequency Comparison - Symmetricom TSG-3800 Series User Manual

Maintenance and Troubleshooting
Troubleshooting Guidelines
To further test the synchronization of the suspected clock or input signal, compare
that signal to an independent signal reference. To compare, apply the suspected
signal to channel A to an oscilloscope and the independent reference, of the same
frequency, to the external trigger (see
stationary, or traverses the oscilloscope display, it is defective.
Figure 4-1.

Frequency Comparison

Forcing a Clock Module Out of Holdover

In some situations the Clock module cannot exit Holdover. This occurs when a bad
reference causes an accumulation history of large frequency and MTIE offsets and
the Frequency/MTIE mode is set to Fail. This history is held even though a good
reference is now available. The stored accumulation error causes the new
reference to fail the 10,000 second measurement interval. It can take up to two
10,000 second intervals (over five hours) to establish a new history.
To prevent accumulated MTIE or frequency data from affecting the current
measurement, use the MTIE or Frequency Inhibit command with the syntax:
MTIE | FREQUENCY {input} INHIBIT
Example
Purpose: Prevent previous MTIE data for the INP1.1 input from causing an MTIE
fault at the end of the measurement cycle.
Command:
MTIE INP1.1 INHIBIT
Response:
>MTIE INP1.1 INHIBIT
05APR2004 10:20:42.130 User A temporarily inhibited MTIE
faults for Inp1.1

Establishing Nominal Phase Setting

The TSG-3800 tracks the phase offset between the input references and the
selected clock oscillator. Upon entry into Acquire mode, the TSG-3800 uses the
phase between the reference in use and the selected clock oscillator, as a reference
phase. The TSG-3800 then attempts to maintain this phase relationship.
120 TSG-3800 User's Guide
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Figure 4-1). If the signal on channel A is not
12778474-002-2 Revision F – March 2004