Spectracom VelaSync 1225, User Manual

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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
Monitoring .
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 sig-
nificant phase offset, or to automatically failover to a different reference if certain qual-
ity thresholds are no longer met.
VelaSync allows Reference Monitoring by comparing the phase data of references
against the System Ontime Point. The phase values shown are the filtered phase dif-
ferences between each input reference 1PPS, and the internal disciplined 1PPS.
The data is plotted in a graph in real-time. The plot also allows you to display historic
data, zoom in on any data range or on a specific reference. A data set can be exported, or
deleted.
To monitor the quality of references, navigate to TOOLS > SYSTEM: Reference Mon-
itor . The Reference Monitor screen will display:
On the left side of the screen, Status information is displayed for the System and the
References. Note that the Reference Status panel also displays the latest PHASE
OFFSET reading (1) for active references against the System Ontime Point. The read-
ing is updated every 30 seconds.
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3.3 Managing References