Discipline Source Phase Measurement
11. Close the Phase Graph and verify that the
Disciplining Status
gets into
Locked
mode.
At this point the test set’s internal “Atomic 10MHz” frequency and “Atomic 1PPS” timing reference signals can be considered accurate and
stable.
The Phase Graph (above) can be used to monitor the short-term stability of the raw GPS clock, which can be used to determine the Discipline
Threshold for a particular site or scenario. Zoom in to the 50ns grid and estimate how dispersed the 1PPS samples are (in ns), then use a
larger value as a threshold. A vertical variation of <30ns is OK.
Clock Disciplining - Using External 1PPS from a PRTC (Cs or Rb)
The TX300s can also be disciplined, faster and more accurately, using a 1PPS reference signal from a traceable time standard (PRTC), which
can be connected to the test set’s ToD port (RS232).
An RJ11-to-BNC cable is required (RJ11 pin 2 to the BNC’s center pin and RJ11 pin 4 to BNC shield/GND). Keep in mind that the same RJ11
form factor comes in 4 and 6-pin versions and this document refers to the 6-pin version.
RJ11 to BNC
1. Go to
>Utilities >Settings >More >High Precision Clock >Atomic Clock.
2. Set
Discipline Source = Ext. 1PPS (RJ11)
.
3. Verify that
1PPS Signal Health = Valid.
TX300s_Platform_Manual_RevB01
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