Spectracom VelaSync 1225, User Manual, Page: 168 / 272

Reported TFOM Value Estimated Time Error (ETE)
8 1 msec < ETE <= 10 msec
9 10 msec < ETE <= 100 msec
10 100 msec < ETE <= 1 sec
11 1 sec < ETE <= 10 sec
12 10 sec < ETE <= 100 sec
13 100 sec < ETE <= 1000 sec
14 1000 sec < ETE <= 10000 sec
15 ETE > 10000 sec
Example
TFOM is a value between 1 and 15. TFOM can never exceed the default MaxTFOM value
of 15.
Typically the MaxTFOM requires no adjustment, but in some instances it may be advis-
able to decrease MaxTFOM so that TFOM can potentially exceed it: For example, by
lowering the MaxTFOM to “5” it is now possible for TFOM to be always higher than the
MaxTFOM value:
Assuming the MaxTFOM is set to 5 and the TFOM happens to go to a 6, i.e. TFOM is
now exceeding MaxTFOM. This condition will cause a 1PPS out of specification alarm
to be asserted and the oscillator disciplining will change in order to speed-up the
alignment of the system 1PPS to the selected reference (causing it to take less time
getting closer into alignment with the reference):
This will cause the TFOM to start to decrease faster. Once TFOM no longer exceeds
MaxTFOM because the System 1PPS is now much closer to the reference 1PPS , the
disciplining slows back down again as the system 1PPS continues to be brought into
alignment with the selected 1PPS input.
3.4.2 Monitoring the Oscillator
The Oscillator Management screen provides current and history status information on
disciplining state and accuracy.
To access the Oscillator Management screen:
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VelaSync User's Manual Rev. 3
3.4 Managing the Oscillator