[time-nuts] GPSDO design articles

Charles Steinmetz csteinmetz at yandex.com
Sun Jul 31 17:34:36 EDT 2016

Finally for today, I posted two white papers from PTF, Inc. that discuss 
the basics of GPSDO design.  These are the best accessible discussions 
of "how it's done" at the professional level that I'm aware of, and 
(IMO) should be required reading for anyone attempting a DIY GPSDO design.

Note that some of the ADEV graphs show the use of local oscillators that 
are less stable at short tau than most time-nuts would use, so the 
corresponding crossover frequencies are lower (PLL bandwidths are 
higher) than would be appropriate for a time-nuts grade GPSDO by a 
factor of ~10.

The file names are:


(Didier's system will convert the underscore characters to spaces for 

Once again, these are still in quarantine, but will be searchable when 
Didier moves them into the general population (which could take several 

When that happens, "PTF" will be a good search term.

Best regards,


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