[LinuxPPS] Offset and jitter of GPS/DCF PPS signals

[Thorsten Mühlfelder]

Hi,

Linux 2.6.28 on the DCF server
Linux 2.6.28rc6 on the GPS server
both with LinuxPPS patch.

ntp 4.2.4p5 was built with the glibc nano patch.

All running on a Slackware based distribution.

Thorsten

PS:
The PCI cards:
Meinberg GPS170PCI v1.10
Meinberg PCI511 v1.00 (dcf)


On Thu, 22 Jan 2009 16:25:41 +0100
Heiko Gerstung <heiko.gerstung at meinberg.de> wrote:

> Thorsten,
> 
> which OS?
> 
> Regards,
>   Heiko
> 
> 
> Thorsten Mühlfelder schrieb:
> > Hi everyone
> >
> > I just wanted to ask what you guys think about my graphs. I'm using 2 servers with Soekris AMD Elan (133MHz) boards: Number one has a Meinberg PCI DCF77 card, number two has a Meinberg PCI GPS card. Both Meinberg cards have a PPS output, too. The servers get their timecode by DCF/GPS and are synchronized by the PPS signal of their own cards.
> >
> > Here you can see how the ntpd on the DCF server sees the PPS signal of the DCF card:
> > http://img-up.net/img/dcf-ppsURM2775K.png
> >
> > Here you can see how the ntpd on the GPS server sees the PPS signal of the GPS card:
> > http://img-up.net/img/gps-ppsoNL9T8F4.png
> >
> > Do you think these values are OK?
> > I think the DCF PPS can't get any better because of the technical specification of DCF77.
> > But I don't know about the GPS server? Is it OK or should it be better? Also I wonder about the constant 15 us jitter value.
> >
> > Greetings
> > Thorsten Mühlfelder 
> >