Spectracom SecureSync User Reference Manual page 207

Oscillator Management History Panel
The graphs in the History Panel plot key oscillator-relevant data over time. For details, see "Mon-
itoring Oscillator Timing Using Graphs" on page 194.
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3 SecureSync User Reference Guide Rev. 18
disciplining control will gradually reduce the phase error over time. Alternatively, restarting
the tracking (see "Restart Tracking" under "Oscillator Disciplining" on page 188) manually,
or automatically via a Phase Error Limit, will quickly reduce the phase error.
10 MHz Frequency Error : An internal estimated calculation (in Hertz) of the internal oscil-
lator's frequency error, based on the phase accuracy error at the beginning and end of a fre-
quency measurement window (the length of this window 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 disciplining sys-
tem. 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 performance (see also the graph
in the History Panel).
: Step size for adjustments to the internal oscillator, as determined by the oscil-
DAC Step
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 SecureSync'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
SecureSync 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 dis-
ciplining. The available TFOM range is 1 through 15.
Max TFOM for Sync : Value, as set under "Oscillator Disciplining Setup" on the next page
Temperature : System temperature, which has an effect on oscillator accuracy, and there-
fore can be used to interpret oscillator performance. The temperature data is also logged.
Note that older SecureSync units may not be equipped with a temperature sensor yet. (Can
be retrofitted, please contact Spectracom.)
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
Frequency Error
DAC Value
System Temperature (if equipped with a temperature sensor).
: [Timestamp: Last occurrence]
: [Timestamp: Last occurrence]
: [Timestamp: Last occurrence]
3.6 OTHER Setup Pages
191