[time-nuts] GPS W/10KHz

Tom Van Baak tvb at LeapSecond.com
Sat Feb 8 15:55:21 EST 2014


> you don't need 10kHz to build a GPS disciplined oscillator. GPSDOs are
> build with control loop response times in the range of some hours, so
> the loop will be absolutely happy with a 1PPS input.

This is quite true, but there are practical issues that cause many people to much prefer 10 kHz instead of 1 PPS. Cheap surplus Jupiter 10 kHz GPS boards are still very attractive for a homebrew GPSDO.

GPSDO designs based on 1 PPS typically use a digital time interval counter. The beauty of using 10 kHz is that one can use analog phase comparisons and thus *avoid* the complexity of microprocessors, software, algorithms, voltage references, and DAC.

The classic example of this is James Miller's ultra simple GPSDO: http://www.jrmiller.demon.co.uk/projects/ministd/frqstd0.htm
You can see it performs extremely well: http://leapsecond.com/pages/gpsdo/

There are dozens of DIY GPSDO projects on the web using the same minimalist design. Use google image search to see them:
https://www.google.com/search?q=GPSDO+Jupiter+10kHz&tbm=isch

Alex -- if you need a concise list of URL's let us know. But I think those images will give you an excellent idea what others have built.

/tvb

--------

> Hi
> where is a good source of GPS receiver modules I need one which has 
> 10kHz output to phase lock a quartz oscillator
> 
> Thank you in advance
> Alex




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