Re: [chrony-users] Re: Locking PPS refclock with NTP source

[Bill Unruh <unruh@xxxxxxxxxxxxxx>]

And how do you know it is worse. The best way would be for you to have an even
better clock source to compare it to. 
Do you have that?


William G. Unruh __| Canadian Institute for|____ Tel: +1(604)822-3273
Physics&Astronomy _|___ Advanced Research _|____ Fax: +1(604)822-5324
UBC, Vancouver,BC _|_ Program in Cosmology |____ unruh@xxxxxxxxxxxxxx
Canada V6T 1Z1 ____|____ and Gravity ______|_ www.theory.physics.ubc.ca/

On Tue, 29 Aug 2017, Thibaut BEYLER wrote:

> Thanks, this is working indeed, but should i get good results (like, not more than a few of micros
> from my gps time) with these settings ?
> Right now it is locking on PPS (*) but my clock seem worse (offset to utc) than when using only the
> ntp server as source.
>
>
> 2017-08-24 17:38 GMT+02:00 Miroslav Lichvar <mlichvar@xxxxxxxxxx>:
>       On Thu, Aug 24, 2017 at 05:18:08PM +0200, Thibaut BEYLER wrote:
>       > I'm trying to synchronise chrony with a pps signal coming from a bnc output
>       > on a gps timeserver.
>       >
>       > The pulses seems to arrive properly according to ppstest, but i don't
>       > figure out how to combine this pulse with a ntp time source to complete the
>       > samples (according to the documentation, it seems to be possible)
>       >
>       > All the exemples i see on the Internet use NMEA (which i don't think I have
>       > out of my pps output) or another reference clock, any way to do that ?
>
> The lock option can work only with other reference clocks. With an NTP
> source you wouldn't specify the option, e.g.
>
> server foo.example.com iburst
> refclock PPS /dev/pps0
>
> After start, chronyd will synchronize the clock to the NTP server.
> This will allow the PPS refclock to complete the pulses and then it
> can take over as the main time source for synchronization of the
> system clock.
>
> --
> Miroslav Lichvar