[time-nuts] GPSDO Alternatives

Chris Albertson albertson.chris at gmail.com
Thu Dec 6 22:57:19 UTC 2012

You'd have to seriously divide down the output from the 10MHz OCXO if you
were going to use it as an interrupt.  Maybe to divide by 10,000? and even
at the higher clock rate you'd still have poor resolution.

I image each interrupt handler would sample some internal counter and the
background task would look at the delta between the two and adjust the DAC
to drive the OCXO to close the difference.   The resolution would be
(maybe?) a "handful" of clock cycles.   Given enough time, say a 1000
second period it might wrk well enough.  I can't know without doing a more
detailed design

On Thu, Dec 6, 2012 at 1:59 AM, Don Latham <djl at montana.com> wrote:

> Chris:
> > The question I have again is about a simple phase detector.
> I did ask if the arduino interrupt ports could be used as a phase
> detector; one on the GPS and one on the OXCO. Too much jitter? If the 12
> MHz clock is too slow, would an 80 MHz clock ARM arduino style processor
> work? I'm simply too new at this to decide.
> Don
> --
> "Neither the voice of authority nor the weight of reason and argument
> are as significant as experiment, for thence comes quiet to the mind."
> De Erroribus Medicorum, R. Bacon, 13th century.
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> Dr. Don Latham AJ7LL
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Chris Albertson
Redondo Beach, California

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