Orolia Spectracom VelaSync 1232, User Manual

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referred to as “Local System” time.
In order for this to happen, VelaSync requires an external Time, or 1PPS reference. In other
words, "Local System" cannot be both Time,
and 1PPS. This makes "Local System" a legit-
imate, traceable reference.
Therefore the "Local System" does not have to be manually set ("validated") by the User
after VelaSync was power cycled (as would be the case with a “User/User” reference).
Since “Local System” cannot be both Time , and 1PPS input together, in this example the
GNSS input will be set as the 1PPS reference (other use cases may require using different
references, e.g. IRIG.)
As there is no default entry for “Local System” and “GPS”, a new entry needs to be added
to the
Reference Priorities table in order to use this combination of references.
Step-by-step procedure:
1.
Add a reference to the Reference Priority by clicking the PLUS icon. Use the fol-
lowing settings, then click
Submit :
In the Priority Level text box, enter 1 . This will give this reference the highest
priority.
In the Time field, select “Local System”.
In the PPS field, select “GPS”.
Check the Enabled checkbox.
2.
Confirm that the first reference in the Reference Priority table has “Local System”
as the Time input and "GNSS" as the 1PPS input.
3.
After a power cycle or reboot, as soon as GNSS is declared valid, the System Time
will automatically be used as-is, with no manual intervention required.
3.3.2 Reference Qualification and Validation
3.3.2.1 Reference Monitoring: Phase
The quality of input references can be assessed by comparing their phase offsets against
the current system reference, and against each other. This is called
Reference Mon-
itoring .
Reference Monitoring helps to understand and predict system behavior, and is an inter-
ference mitigation tool. It can also be used to manually re-organize reference priorities e.g.,
by assigning a lower reference priority to a noisy reference or a reference with a significant
phase offset, or to automatically failover to a different reference if certain quality
thresholds are no longer met.
3.3 Managing References
CHAPTER
3
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