[time-nuts] M12 100 Hz vs. 1PPS measurements

[WarrenS]

Ulrich

Thanks, I'd forgot about that, I'll certainly check it out better this time.
The PSR10 being a Rb and not a OCXO, I would expect the best type of tracking filter used there to be somewhat different, and I mean in more ways than  just a longer time constant. Last I looked, I  thought that I saw was that they just set their simple filter to about 20 hrs.

WarrenS
**************
----- Original Message ----- 
From: "Ulrich Bangert" <df6jb at ulrich-bangert.de>
To: "'Discussion of precise time and frequency measurement'" <time-nuts at febo.com>
Sent: Saturday, December 06, 2008 9:06 AM
Subject: Re: [time-nuts] M12 100 Hz vs. 1PPS measurements


> Warren,
> 
> if you consider Stanford Research as a producer of a "better GPSDO" you
> can download their PRS10 manual from their web pages. It contains all
> the math that you are asking for.
> 
> Best regards
> Ulrich
> 
>> -----Ursprungliche Nachricht-----
>> Von: time-nuts-bounces at febo.com 
>> [mailto:time-nuts-bounces at febo.com] Im Auftrag von WarrenS
>> Gesendet: Samstag, 6. Dezember 2008 16:04
>> An: Discussion of precise time and frequency measurement
>> Betreff: Re: [time-nuts] M12 100 Hz vs. 1PPS measurements
>> 
>> 
>> 
>> Tom, 
>> This is great work and Information to see.
>> I do think that this will inspire, and make if not a giant 
>> leap, at least a small step to better GPSDO performance. 
>> 
>> 1st question:
>> Does anyone have or can they tell me where to get a copy of 
>> the actual raw data Tom used for these plots? 
>> http://www.leapsecond.com/pages/m12-adev/
>> 
>> The Link on his leapsecond site to the raw data seems to be 
>> missing. www.LeapSecond.com/logs/ - Logbook and raw data (ask) 
>> A request to Tom, so far has gone unanswered.
>> 
>> 2nd question 
>> Can anyone provide me with the filter formula or algorithm or 
>> any information 
>> regarding that is used by any of the better GPSDO units to 
>> calculate the ECV 
>> Dac output voltage.
>> 
>> I know about the simple basic 1st order averaging  filter 
>> used in some of the units, 
>> and the even more basic but effective over under check to 
>> increment / decrement 
>> an accumulator.  BUT it would seem to me there has got to be 
>> filters that give much 
>> better result than either of these available and being used out there.
>> 
>> Allan deviation (ADEV) and Modified Allan deviation (MDEV) 
>> http://www.mail-archive.com/time-nuts@febo.com/msg07211.html
>> 
>> 
>> 
>> 
>> I'm looking for just the basic formula used to process the 
>> phase error data before 
>> being applied to the DAC. I am not looking for anything 
>> secrete or with all the extra 
>> things some use to verify that the data is valid or 
>> appropriate before being applied 
>> or thrown away.
>> 
>> Thanks, for any information you can provide me.
>> WarrenS
>> 
>> **********************
>> 
>> 
>> ----- Original Message ----- 
>> From: "Tom Van Baak" <tvb at LeapSecond.com>
>> To: "Discussion of precise time and frequency measurement" 
>> <time-nuts at febo.com>
>> Sent: Friday, December 05, 2008 12:32 AM
>> Subject: [time-nuts] M12 100 Hz vs. 1PPS measurements
>> 
>> 
>> >I know a number of you have been waiting for the results of  
>> this M12 
>> >experiment. I compared the performance of a 100 Hz  output 
>> vs. a 1PPS 
>> >output vs. a 1PPS with sawtooth correction.
>> > 
>> > http://www.leapsecond.com/pages/m12-adev/
>> > 
>> > I think it came out quite well and it may surprise some of you.
>> > 
>> > /tvb
>> > 
>> > 
>> > 
>> > 
>> >
>> 
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> 
> 
> 
>