[time-nuts] GPSDO Alternatives

Don Latham djl at montana.com
Fri Dec 7 01:48:15 UTC 2012


Chris: yes, dividing would have to be done. Doesn't TVB have a simple
divider block?
You don't really have to "close" the difference, just maintain it?
Don L
Chris Albertson
> 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.
>> "If you don't know what it is, don't poke it."
>> Ghost in the Shell
>>
>>
>> Dr. Don Latham AJ7LL
>> Six Mile Systems LLP
>> 17850 Six Mile Road
>> POB 134
>> Huson, MT, 59846
>> VOX 406-626-4304
>> www.lightningforensics.com
>> www.sixmilesystems.com
>>
>>
>>
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>
>
>
> --
>
> Chris Albertson
> Redondo Beach, California
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-- 
"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.
"If you don't know what it is, don't poke it."
Ghost in the Shell


Dr. Don Latham AJ7LL
Six Mile Systems LLP
17850 Six Mile Road
POB 134
Huson, MT, 59846
VOX 406-626-4304
www.lightningforensics.com
www.sixmilesystems.com





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