[ntp:questions] Re: PPS signal that's not synchronized with second boundaries

Ronan Flood ronan at noc.ulcc.ac.uk
Wed Jun 28 13:42:12 UTC 2006


On Mon, 26 Jun 2006 09:21:22 +0200,
"Maarten Wiltink" <maarten at kittensandcats.net> wrote:

> "Hal Murray" <hmurray at suespammers.org> wrote in message
> news:_--dnTaJHdp4oALZnZ2dnUVZ_vKdnZ2d at megapath.net...
> 
> > Suppose I had something like a Rubidium oscillator that makes
> > a nice PPS signal, but it's not synchronized to a second boundary.
> >
> > Is there any way to take advantage of that?
> 
> If I've understood past news correctly, you can connect it as a
> PPS source and, once you have an idea of its offset, tinker/fudge
> it so it does appear synchronised to the second boundary.
> 
> The bad news is that my recollection of said past news is also that
> this didn't quite work then. I think the offset correction was
> applied at the wrong point, so it still appeared off-beat. But
> perhaps that got fixed in the meantime.

I hope so, as that's how we're planning to hook-up a Rubidium oscillator,
using refclock_atom!  Without kernel/hardpps, i.e. flag3=0.

Note that we expect to have to alter the fudge regularly to track Rb aging.

-- 
                      Ronan Flood <R.Flood at noc.ulcc.ac.uk>
                        working for but not speaking for
             Network Services, University of London Computer Centre
     (which means: don't bother ULCC if I've said something you don't like)




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