[ntp:questions] Something for distributing a PPS signal?
David J Taylor
david-taylor at blueyonder.co.uk.invalid
Sat Jul 2 05:51:27 UTC 2011
"E-Mail Sent to this address will be added to the BlackLists"
<Null at BlackList.Anitech-Systems.invalid> wrote in message
news:iulje3$ahd$1 at dont-email.me...
[]
> Unless I'm off by a magnitude somewhere;
>
> Copper wire is about 0.3m/ns? 100m ~= 333+ns?
>
> The differences in e.g. PC serial port implementations
> between different PPS recipients may easily cause a
> difference of that much.
You are missing the velocity factor of typical cable, which slows the
signal down to 5ns/m (round figure). But it doesn't affect your basic
argument that cable delays are insignificant compared to different
hardware implementations, not to mention differences in OS interrupt
latency and response times.
Cheers,
David
More information about the questions
mailing list