[time-nuts] Setting up PRS10 with M12+T GPS

Magnus Danielson magnus at rubidium.dyndns.org
Wed May 2 20:11:25 UTC 2012


On 05/02/2012 10:03 PM, Azelio Boriani wrote:
> You don't have a Cs reference but you have a GPS: in the long term it is
> the same. By using a TIC (your preferred: HP5370B, HP5372A, SR620, PM6680,
> PM6681, HP53132A, Racal 2351, Yokogawa TA720, PICTIC II, Wavecrest DTS275
> [SIA3000?] and others) keep track of the GPS PPS vs. the PRS10 PPS.

Considering the M12+T PPS noise, you won't need anything stellar. A 
PICTIC II will do just fine... or if you trust the PRS-10 readings, run 
from that.

What would make this better would to use a sawtooth-correction to PPS 
delay setup, as the PRS-10 measurement resolution will be about on par 
with that. Would lower the effects of hanging-bridges, even if one 
suffers less when dealing with a rubidium.

Adjust the PRS-10 PLL bandwidth/time-constant, the default value is most 
probably not optimum, you can go further up in time. Do check the manual.

Cheers,
Magnus

> On Wed, May 2, 2012 at 9:46 PM, Jerry Mulchin<jmulchin at cox.net>  wrote:
>
>> I need some guidance from the collective.
>>
>> I just finished rebuilding my PRS10 lab standard and it is now using a
>> M12+T GPS module.
>> I have completed my site survey and it is now in "hold position mode",
>> TRAIM is enabled
>> with 500ns alarm setting and the 1PPS is enabled during non-TRAIM alarm
>> conditions.
>>
>> The PRS10 is set for default 1PPS steering, but all of the other
>> parameters are just as
>> I received the unit 5 years ago.
>>
>> My questions are these;
>>
>> 1.) Should I reset the PRS10 to its Default settings or just adjust
>> selected parameters to
>> align the unit for proper operation with the M12+T unit? And if that is
>> the case, what parameters
>> need adjusting?
>>
>> 2.) Are there any special settings, other than what WinOncore sets, that I
>> should make to the
>> M12+T unit?
>>
>> 3.) After all this is completed, how do I know that the PRS10 is properly
>> tracking GPS and
>> maintaining frequency accurately? I don't have a Cesium reference, but I
>> do have an un-disiplined
>> LPRO-101, but I don't think that really helps me determine frequency
>> accuracy.
>>
>> I will be adding the sawtooth correction eventually to the M12+T 1PPS
>> output, but observed
>> negative sawtooth with WinOncore shows +/- 14ns changes with some bridging
>> occasionally.
>>
>> While I don't ever want to claim NIST traceability, I would like to be a
>> close as possible, and I
>> guess that is the bottom line need here. So what else do I need to do to
>> get as close as possible?
>>
>> Thanks for any help.
>>
>>
>>
>>
>> Jerry Mulchin
>>
>>
>>
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