Orolia Spectracom EC20S - Page 30

EPSILON CLOCK MODEL EC20S Spectracom
User’s Manual 30
• Holdover : The oscillator disciplining has been suspended because there is no valid
synchronization source to synchronize to. The oscillator control remains steady on the last valid
value.
• Forced Holdover: The oscillator disciplining has been suspended upon user request (see 13.7.3
Force Holdover). The oscillator control remains steady on the last valid value.
• Degraded : Hidden status occurring when all synchronisation sources are lost (and so the
oscillator disciplining is suspended) while the oscillator disciplining was in ‘Locked’ status. If no
synchronization source is selected before the end of a latency delay (factory programmable), an
urgent alarm is raised and the oscillator disciplining transits to the ‘Holdover’ status. But if a
synchronization source is selected before the end of the latency delay, the oscillator disciplining
resumes (no alarm will be raised).
The SFN conditions are defined by the SFN Status (SFN ‘On’: the EC20S meets the SFN conditions; SFN
‘Off’: the EC20S doesn’t meet the SFN conditions) as follows:
Disciplining Status as defined just above
SFN Status (Ref. 4)
‘Warming up’
SFN Off
‘Tracking Search’
SFN Off
‘Locked’ (see just above for the definition of the ‘Locked’ conditions)
SFN On
‘Holdover’ coming from the ‘Tracking Search’ status
SFN Off
‘Holdover’ coming from the ‘Locked’ status
and the phase accuracy is below the ‘Alarm Phase Threshold’ (see 13.7.3) AND
the frequency accuracy is below the ‘Alarm Frequency Threshold’ (see 13.7.3).
SFN On
‘Holdover’ coming from the ‘Locked’ status
and the phase accuracy is above the ‘Alarm Phase Threshold’ (see 13.7.3) OR
the frequency accuracy is above the ‘Alarm Frequency Threshold’ (see 13.7.3).
SFN Off
‘Forced Holdover’
SFN On