[time-nuts] A question about GPS pps quality.
Poul-Henning Kamp
phk at phk.freebsd.dk
Thu Jul 26 11:46:29 EDT 2007
In message <46A8C00D.50603 at kudra.com>, Robert Sexton writes:
>); SAEximRunCond expanded to false
>1. If I interface one of these to my closet-based server, do I really
>have a Stratum-1 source? 1us accuracy doesn't sound all that great, but
>I'm nut so sure that the server can take advantage of a pulse with
>greater accuracy.
Stratum-1 - certainly. 1us accuracy ? Highly unlikely.
The clock crystal in your computer is far too temperature sensitive
for that.
>2. Would I get significantly better performance if I shelled out $75
>for one of the new trimble timing GPS modules, or found an old oncore
>timing module on ebay?
No.
>I know that the oscillator on my old AMD based UNIX machine isn't all
>that great, but I'll leave that question for another time.
That is where you should spend your money first.
Any GPS with a PPS output is sufficient to what you can do with a
normal clock crystal.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
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