[time-nuts] Discipline an oscillator with NTP?

[Chris Albertson]

This is exactly what an NTP server does.  It adjusts the rate of a
local clock so that the local clock advances at the same rate is the
set of Internet servers that have passed a clock selection test.   NTP
does this very well considering the uncertainly of the lag over the
internet.   There is a good argument the NTP is optimal but the best
you can get using Internet time servers is "about a milli second" or
0.001 second.

It would be nearly trivial to write software to produce a PPS output
on one of the control line of a serial port.   SO you NTP disciplined
computer can produce PPS with about .001 second error

Send this PPS to the "normal" GPSDXO in place of the GPS' PPS.  The
computer is "only" about 1000 times worse than a GPS and might work OK
if you drastically increase the time constant on the GPSDXO's control
loop.

 I think your "NTPDXO might be as good as GPSDXO is measured over a
long enough period, like months.  Short term it might be about as good
as the TTL can oscillator inside the PC.

On Fri, Jul 22, 2011 at 11:27 AM, Jason Rabel
<jason at extremeoverclocking.com> wrote:
> I was just thinking (dangerous I know)... Has anyone attempted to build a stand-alone oscillator that is disciplined via NTP?
>
> i.e. NTP keeps it on-frequency... And I'm not talking about NTP that is locked to a local GPS, I'm curious about purely syncing to
> other NTP servers over a network. (The presumption is that you have no access to GPS, WWVB, Cellular, or similar.)
>
> Is it even possible or am I just day dreaming?
>
>
>
>
>
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-- 

Chris Albertson
Redondo Beach, California