[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.

These are my opinions.  I hate spam.

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