[ntp:questions] PPS and NMEA

unruh unruh at invalid.ca
Mon Sep 10 14:55:35 UTC 2012

On 2012-09-09, ksprabha <prabhaka.k at gmail.com> wrote:
> Hi,
> Kindly let me know what is the difference between NTP with PPS and NTP with out PPS.

PPS refers to "pulse per second". IF you have some external source which
delivers a signal once per second (eg a gps receiver with PPS output)
then ntpd will use that to make sure that the clock registers .000000 at
the beginning of that pulse. 
If the PPS is accurately timed, then your system time will be accurately
set as far as the seconds turnover is concerned. 

> Thanks
> Prab

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