Safran VersaSync User Manual page 238

3.4 Managing the Oscillator
3. Populate the fields:
Maximum TFOM for Sync: When TFOM (Time Figure of Merit, see also
"Time Figure of Merit (TFOM)" on the facing page) is greater than
Max TFOM, disciplining will still be attempted against the selected ref-
erence to improve the TFOM. If the condition persists, the system will
transition to holdover, and eventually out of sync. When disciplining is
performed such that TFOM is no longer greater than max TFOM, the
system will transition back into sync.
Holdover Timeout(s): The default is 7200 s (= 2 hours).
For more information on holdover timeouts, see "Typical Holdover
lengths in seconds" on page 222. For additional information on hold-
over, see "What is "Holdover Timeout"?" on page 220.
Phase Error Limit: [Default=0 (disables this feature)]. Setting a Limit
(valid for +/-) for the Phase Error between an external 1PPS reference
and the System 1PPS will cause the disciplining tracking to restart
automatically (after a few minutes delay) if that limit is exceeded. This
will help to quickly re-align the System 1PPS with a reference.
When using a Host Reference as a primary or backup reference, for
improved performance it is recommended to set the phase error limit
for NTP to a suggested value of 100000 ns (= 100 µ second). Adjust
this value as needed, based on your accuracy requirements.
Restart Tracking: Check this box, and click Submit if you want to
manually restart disciplining tracking.
This option causes the disciplining algorithm to stop tracking the
input reference and start over (as if it was just acquired). This can be
useful if there is a large phase offset between reference 1PPS and sys-
tem 1PPS, as it may occur when going back into sync to the external
reference after a long holdover. A Restart Tracking will re-align the
system 1PPS with the reference 1PPS very quickly, but may cause the
1PPS output to jump.
Recalibrate: In rare cases, existing calibration data may no longer be
suitable to calibrate the oscillator. This function will delete the
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