Smartclock; Bestime - Symmetricom TimeProvider 1000 User Manual

These output formats automatically generate SSMs. The system output quality level
depends on the input quality level of the input signal or the local oscillator's quality
level. During normal operation, when a qualified input is used as the active timing
reference, the TimeProvider copies the input's quality level to all DS1 ESF outputs
and E1 CAS4 outputs. T1 SSM messages are mapped to the corresponding
equivalent E1 SSM message and vice versa.
If the IOC is operating in Holdover mode for any reason, the SSM quality is the
internal level of the oscillator installed in the IOC.

SmartClock

The TimeProvider uses Symmetricom's SmartClock technology, which predicts
frequency changes due to aging of the local oscillator in the IOC; this offsets this
deterministic behavior by steering the output with a corrected deviation.
The TimeProvider begins the learning process as soon as you apply a valid external
reference source. The SmartClock technology is enabled after 24 hours of
continuous lock; the TimeProvider then issues an event message similar to this:
IOC1,EQPT,NA,SCAVAIL,NSA,04-12-14,12:13:14:\"SMARTCLOCK
ALGORITHM, ENABLED\"
If you reset the IOC or if the oscillator becomes less stable (for example, due to
extreme temperature swings), the TimeProvider disables SmartClock and issues an
event message similar to this:
IOC1,EQPT,NA,SCAVAIL,NSA,04-12-17,15:16:17:\"SMARTCLOCK
ALGORITHM, DISABLED\"
The TimeProvider automatically restarts SmartClock, which then begins to
determine a new aging rate for the oscillator.

BesTime

The TimeProvider uses Symmetricom's BesTime algorithm when it is in the PRR
mode to provide enhanced GR-2830-CORE performance during bridging or
holdover situations. BesTime minimizes the effect of transients on the reference
signal on the outputs of the TimeProvider by comparing them against the system
reference to produce the most stable outputs from the TimeProvider.
097-58001-02 Revision C – August 2005
Chapter 1 Overview of the TimeProvider
SmartClock
TimeProvider User's Guide 39