E1 card oscillator replace, timing accuracy problem

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Sipos Csaba dchardware at gmail.com
Fri Oct 4 11:32:07 UTC 2013


Hi Guys,

I am working with Nokia InSite and MetroSite units and now it is
obvious, that I have a timing accuracy problem with my E1 dahdi card.
According to "dahdi_test" I have a magnitude worse accuracy compared
to the GSM specs. I can measure 99.995% accuracy compared to the
required 99.99975%.

MY question is what can I do about it? My first idea was to replace
the oscillator on the card, which by default has a 20ppm oscillator on
it. I was able to find some 10ppm oscillators but they are not
matching the required frequency (8.192MHz).

It would be nice to hear some ideas about how can I solve this issue.

Thanks!

BR,
Csaba





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