[time-nuts] Some results of PRS10 and Trimble Resolution

[Poul-Henning Kamp]

In message <20060627134736.6784.qmail at web53702.mail.yahoo.com>, Radio Engineer 
writes:

>  I still don't really understand why the PRS10 Rubidium has such a bad 2s 
>Allan Deviation with a 7-hour 1PPS filter time, also considering this kind of 
>nice low Phase noise. 

If you feed a PRS10 with a 1PPS that has systematic jitter (NB: not
random jitter!) like the Oncore GPS receivers have, then some heavy
duty averaging is called for before the loop is fed.

Unfortunately the 1/256'th exponential filter provided in the PRS10
is not long enough to fill this need.

Newer versions of the PRS10 firmware allows you to set the PPS input
offset, and with a small program you can transmit the negative sawtooth
correction from the GPS to the PRS and that solved the problem for me.

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