Spectracom VelaSync 1225, User Manual

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dow will vary depending upon the type of oscillator installed and the oscillator
adjustment algorithm).
Current DAC Setting : Current DAC value, as determined by the oscillator dis-
ciplining system. The value is converted into a voltage that is used to discipline the
oscillator. A stable value over time is desirable and suggests steady oscillator per-
formance (see also the graph in the History Panel).
DAC Step : Step size for adjustments to the internal oscillator, as determined by
the oscillator disciplining system. Larger steps = quicker, but coarser adjust-
ments. 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 synchronized 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 estimated error is too large, it could adversely affect
the performance of oscillator disciplining. The available TFOM range is 1 through
15.
Max TFOM for Sync : Value, as set under "Configuring the Oscillator" on page 153
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 His-
tory panel on the right, while graphs for board and CPU
temperature can be found under TOOLS > SYSTEM: Sys-
tem Monitor .
Last Time Reference Change : [Timestamp: Last occurrence]
Last 1PPS Reference Change : [Timestamp: Last occurrence]
Last TFOM Change : [Timestamp: Last occurrence]
Last Sync State Change : [Timestamp: Last occurrence]
Last Holdover State Change : [Timestamp: Last occurrence]
The Oscillator History Panel
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CHAPTER
3
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VelaSync User's Manual Rev. 3
3.4 Managing the Oscillator