Patrick, I don't know of an analog approach using the 1 pps divided to 0.5 Hz (for 50% duty cycle) as input to a phase detector. 1 Hz ripple frequency from the phase detector is probably not practical to filter. You would need a low pass filter time constant of at least 1000 seconds and I think capacitors that will work for the long time constant will have poor temperature properties, leading to excess drift. Digital approaches using the 1 pps signal compared to a divided OCXO signal are used by most modern designs. Bob Q. ----- Original Message ----- From: "Patrick Reynaert" <[email protected]> To: "time-nuts" <[email protected]> Sent: Sunday, December 21, 2008 2:13 PM Subject: [time-nuts] Jupiter modules: 1pps or 10kHz to lock an OCXO ?
> Hello, > > > Using the 10kHz output to lock an OCXO is common practice and seems to > give good results. > > Has anyone tried to use the 1pps output? One? could first make a simple > divider to create a 0.5Hz reference with 50% duty cycle, and then use this > signal to lock an OCXO. This would also allow the use of other OEM GPS > modules that don't have the 10kHz but only the 1pps signal. > > Of course, as the 0.5Hz signal is much lower in frequency than 10kHz, the > short-term stability is pushed more to the OCXO, making the requirements > of the OCXO even harder. > > But maybe the 1pps signal has better stability than the 10kHz signal? Or > is this the same since these signals will only influence the long-term > stability of the oscillator and have the same accuracy? > > Any thoughts are highly appreciated. > > Thanks, > Patrick. > > > > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
