Spectracom PRISMA VelaSync User Manual page 159

The Oscillator History Panel
The Oscillator History Panel offers real-time graphical monitoring of VelaSync's internal timing.
The following graphs plot key oscillator-relevant data over time::
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3 VelaSync User's Manual Rev. 1
value over time is desirable and suggests steady oscillator performance (see also the
graph in the History Panel).
DAC Step : Step size for adjustments to the internal oscillator, as determined by the oscil-
lator disciplining system. Larger steps = quicker, but coarser adjustments. The step size is
mainly determined by the type of oscillator.
TFOM : The Time Figure of Merit is VelaSync's estimation of how accurately the unit is syn-
chronized with its time and 1PPS reference inputs, based on several factors, known as
the Estimated Time Error or ETE. The larger the TFOM value, the less accurate VelaSync
believes it is aligned with its 1PPS input that is used to perform disciplining. If this estim-
ated error is too large, it could adversely affect the performance of oscillator dis-
ciplining. The available TFOM range is 1 through 15.
Max TFOM for Sync : Value, as set under "Configuring the Oscillator" on page 143
Temperature(s) : Three temperatures are displayed:
Oscillator temperature, which has an effect on oscillator accuracy, and therefore
can be used to interpret oscillator performance.
Board temperature (measured on the main board, sometimes also referred to as
'System temperature')
CPU temperature
Note: Oscillator temperature is plotted over time in the
on the right, while graphs for board and CPU temperature can be
found under
Last Time Reference Change
Last 1PPS Reference Change
Last TFOM Change : [Timestamp: Last occurrence]
Last Sync State Change : [Timestamp: Last occurrence]
Last Holdover State Change
Phase Error Magnitude : See
10_MHz_Frequency_Error
Frequency Error : See
DAC Step
Scaled DAC Value : See
Oscillator Temperature , which has an effect on oscillator accuracy, and therefore can be
used to interpret oscillator performance.
TOOLS > SYSTEM: System Monitor
: [Timestamp: Last occurrence]
: [Timestamp: Last occurrence]
: [Timestamp: Last occurrence]
1PPS Phase Error
3.4 Managing the Oscillator
History panel
.
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