[time-nuts] PRS-10 temperature sensitivity (and Lady Heather support)

Mark Sims holrum at hotmail.com
Wed Jul 19 23:10:21 EDT 2017

I did a simple test run. driving the 1PPS input with a Tbolt..  over 2 hours the reported PRS case temperature varied 0.8 C.  The TT time tag varied 60 ns (75 ns / degree).   The FC frequency control word varied the frequency by  0.231 ppt (0.300 ppt / degree).   All my high res counters are tide up doing other things, so I could not measure the actual freq.

It looks like the PRS10 time tag processor / interpolator is rather crappy.   I need to feed it the 1PPS from a 5071A to eliminate any temperature effects on the Tbolt.

I did modify the message polling code to read the case temperature every second.  That increased the time needed to get all the data values from the PRS10 to 35 seconds... a 10 second increase,   You can only get around 5 values per second from the PRS10 and there are around 50 values it can report.  If three of those 5 values per second are TT, FC, and AD10 that leaves room for getting 2 of those 50 values per second.


> Have you done a least-square fit to determine the sensitivity?

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