Managing The Oscillator; Configuring The Oscillator - Safran VersaSync User Manual

lost again moments later, the Holdover timer starts again with its full value. If its
set to one week in this case, it then gets another week of Holdover operation
before NTP goes to Stratum 16 (if GPS remained unavailable for the entire week).
Holdover mode and the User/User reference
If the only available input reference is a manually set User time, and VersaSync is
subsequently rebooted or power cycled, time sync will be lost when VersaSync
powers back-up. The time will need to be set manually again in order for Ver-
saSync to return to its fully synchronized state. See
on page 177
3.4

Managing the Oscillator

The purpose of the built-in oscillator is to provide VersaSync with an accurate
and very stable internal frequency source. This allows VersaSync to go into a
holdover mode in the event that external time or frequency references are lost or
become invalid. However, the oscillator can also be used as a legitimate 1PPS ref-
erence during normal operation, in conjunction with an external time reference
(for more information, see
VersaSync's internal oscillator is normally disciplined to an input reference (such
as GNSS, IRIG input, 1PPS input, etc.) in order to provide the highest degree of
oscillator accuracy and to account for oscillator drift. While disciplining (with a
1PPS input reference input present and valid), the oscillator's output frequency is
monitored and based on the measured frequency, the oscillator is steered to
maintain a very accurate 10 MHz output. If no valid 1PPS input references are
present (or input references are present but not considered valid), the oscillator
will be in Freerun mode instead.
The Oscillators Settings page provides the user with some control of the dis-
ciplining process. This page is also used to configure the length of time Ver-
saSync is allowed to remain in the Holdover mode when all references are lost.
3.4.1

Configuring the Oscillator

VersaSync is equipped with an internal oscillator. To configure the oscillator set-
tings:
CHAPTER •
3 VersaSync User Manual Rev. 12
and "Manually Setting the Time" on page 161
1. Navigate to MANAGEMENT > OTHER:
2. Click the GEAR icon at the top of the
window will display:
"Configuring Input Reference Priorities" on
Disciplining.
Status
3.4 Managing the Oscillator
"The "User/User" Reference"
for more information.
panel. The Oscillators Settings
page 173.)
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