[time-nuts] Disciplining Rubidium

SAIDJACK at aol.com SAIDJACK at aol.com
Thu Apr 24 20:09:39 EDT 2008

Hi Antonio, Tom,
recently I had to unplug my PRS10 Rb from GPS for about 3 days. It drifted  a 
couple 100ns in that time frame.

When I plugged the GPS 1PPS back in, I saw a significant  frequency error of 
a couple of parts to the E-10 while the PRS10 was shifting  the 1PPS back onto 
Pretty bad for a Rubidium I thought.
For such a large phase error I would have expected the PRS10 to just reset  
the 1PPS rather than drift it.
I may have to adjust the loop time constants to be more than 7 hours.
To address your question: I would expect the PRS10 to behave in a  similar 
manner when turning it upside down. It would probably take some  minutes or 
longer to re-lock the OCXO to Rb, then correct the OCXO to  1PPS phase error that 
Typical OCXO errors for a turn-over test are parts in E-09, that causes a  
very significant immediate phase drift.
Can't try it in my setup unfortunately.
In a message dated 4/24/2008 15:28:55 Pacific Daylight Time,  
iovane at inwind.it writes:

Why the  XO in a GPS-Rb-XO version should not bear this problem?
I understand that  Rb itself shouldn't, but what about the controlled XO?
(I have an interest  in orientation sensitivity of measuring  instruments).

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