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

Azelio Boriani azelio.boriani at screen.it
Wed May 2 20:30:45 UTC 2012


Magnus, you are correct but can I avoid to list our beloved
counters/analyzers? The time-nut main tool is the TIC.
Anyway, to correct the PPS input for the PRS10 the hardware approach is a
must: so a delay line and a microprocessor are needed. Unless the SRS can
develop a suitable software for the PRS10 (an inverted TTL serial line is
already present) to read the M12+.

On Wed, May 2, 2012 at 10:11 PM, Magnus Danielson <
magnus at rubidium.dyndns.org> wrote:

> 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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>
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