John, I think the best of all worlds would be a double-ovenized SC-cut OCXO running at 5 MHz (lower mass). These OCXOs have the lowest phase noise and best Allen variance short term stability (1-100 seconds) of any xtal or Rb. Then have this OCXO disciplined by the GPS, with an ephemeris of variations constantly collected, statically averaged over a long period (at least 1 month), and the calculated average used to adjust the OCXO frequency.
Tom Tom Duckworth 510-886-1396 -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of John Miles Sent: Wednesday, April 23, 2008 8:02 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Disciplining Rubidium Adding to Tom's worthy list: 11) Short-term phase noise; the GPS-Rb sources don't seem to be as clean as the better GPS-OCXO packages. -- john, KE5FX > > More precisely, if I had two black boxes, one containing > > a GPS-Rb-XTAL setup and another containing GPS-XTAL, > > what measurement would you make from outside the boxes > > to distinguish from one another? > > Ah, clever question. Here's ten ways to distinguish them... > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.