Poul-Henning Kamp wrote: > In message <[EMAIL PROTECTED]>, Dr Bruce Griffiths writes: > > >>> A quantum of 1ns is not a concern if the attack point for the PLL >>> is on the order of hours. >>> >>> >> This statement is only true when one is disciplining or monitoring >> relatively with sufficiently large frequency and/or phase instabilities. >> When one wishes to discipline an Oscilloquartz 8607 OCXO for example >> every nanosecond or fraction thereof matters. >> > > As far as I can see on TVB's site, the 8607 is about [EMAIL PROTECTED] sec, > so 1ns/1h sounds perfectly good to me. > > Only true when one only considers the data available on Tom's site. Quartzlock have a GPS disciplined BVA OCXO that achieves considerably better stability, admittedly their carrier phase tracking GPS receiver has a resolution of a few picoseconds for an integration time of 1 second. >> Its not the coherence of the sawtooth but the coherence between the >> oscillator clocking the timer used to position the PPS signal and the >> frequency of the PPS signal itself. >> > > Yes, those are non-coherent, that is why we need the negative sawtooth > in the first place. If they were coherent, we could just have > used a formula. > But they are not sufficiently incoherent as hanging bridges and the quasi periodic form of the sawtooth error amply demonstrate.
Bruce _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
