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 NetClock’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 NetClock
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 page215
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 History panel
on the right, while graphs for board and CPU temperature can be
found under TOOLS > SYSTEM: System Monitor.
Note that a temperature sensor started being added to NetClock Model 9483s in 2012
(the Model 9489s do not have this sensor installed). Model 9483s purchased prior to
this hardware change being implemented will not be able to report the internal tem
perature, even with software update versions 5.2.0 or above installed.
For more information, see "Temperature Management" on page288.
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
The Oscillator History Panel offers real-time graphical monitoring of NetClock’s internal tim
ing. The following graphs plot key oscillator-relevant data over time::
220
CHAPTER 3 • NetClock User Reference Guide Rev. 16
3.5 Managing the Oscillator
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