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

[Thorsten Mühlfelder]

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