[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?


>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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