[time-nuts] GPSDO Alternatives

Hal Murray hmurray at megapathdsl.net
Thu Dec 6 23:16:52 UTC 2012


albertson.chris at gmail.com said:
> 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 

Do some of the counter/timer modules have an option to run the counter off an 
internal clock and copy the value into another register on an external signal?

That avoids any interrupt latency.




-- 
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