[ntp:questions] Driver Help?

Hal Murray hal-usenet at ip-64-139-1-69.sjc.megapath.net
Wed Jun 13 18:08:35 UTC 2007


>The resolution of 1 second is a killer.  This is going to make the 
>jitter a function of exactly when each poll is received.  I doubt that 
>ntpd cares very much exactly when a poll is sent.  If this device has a 
>PPS output, it might be useable. . . .

Some GPS units can be put into a mode where they send a report
on each second tick.  So although the resolution in their
data format is only one second, you get the message close
to that second tick.

There might be an option in the polling mode where it
waits until the second ticks before answering.

You might be able to fake it by polling every few ms until you
see the answer change.  Then you know that the second ticked
between two polls so your time resolution is the poll interval.
Skipping the useless polls is left as an exercise ....

-- 
These are my opinions, not necessarily my employer's.  I hate spam.




More information about the questions mailing list