In message <[email protected]>, Bob Camp writes: >Hi > >By far the most common approach to optimizing these is the "measure >it and see" approach. > >1) measure the noise out of the GPS ( must be done no matter what) >2) measurer the noise of the specific OCXO (again must be done) >3) *guess* at a cross over >4) try it and measure the result. >5) step and repeat 3 and 4 until exhaustion sets in
Indeed. What I've done is to automate that, using the zero-crossing frequency of the residual as input. >If you simply try a dynamic tune approach, you never really get >to an optimum point. For the stuff I did, hitting the optimum point exactly from the beginning, was not nearly as important as getting close to the optimum point when circumstances changed. But with that being said: Even in the "ideal scientific" setting, I think my approach is not only valid, I think it is one of the most efficient ones, because you don't need a 3rd reference to measure against. If you have a 3rd (& better) reference, by all means use it, but if all you have is a GPSDO, my method delivers better results than I have seen from anything else. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 [email protected] | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. _______________________________________________ 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.
