They have their own cross-correlation system; it's not highly automated but claims -190 dBc/Hz capability: http://www.wenzel.com/pdffiles1/PNTS%201000/BP-1000-CC.pdf
John On Aug 4, 2012, at 7:31 PM, Azelio Boriani <azelio.bori...@screen.it> wrote: > In your opinion, how the Wenzel company got the data for the ULN > specifications? > > On Sat, Aug 4, 2012 at 11:02 PM, Bruce Griffiths <bruce.griffi...@xtra.co.nz >> wrote: > >> John Ackermann N8UR wrote: >> >>> Magnus inspired me to try my own cross-correlation experiment with the >>> TimePod today. I used two fairly normal OCXO frequency standards as the >>> reference, and a Wenzel 5 MHz ULN as the device under test. >>> >>> By doing single-reference measurements of each OCXO versus the ULN, I was >>> able to plot their noise. Since the ULN has performance near the noise >>> floor of the TimePod, I could then test how well the correlation works to >>> allow measurements below the noise of either reference. >>> >>> Conclusion: it works *really* well. Plots and a little write-up are at: >>> http://www.febo.com/pages/cross-correlation/index.html >>> >>> John >>> >>> _______________________________________________ >>> 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. >>> >>> Even a pair of Trimble 34310T ocxos appear to work well as the dual >> reference oscillators. >> >> If one could use a pair of ocxos to drive the other pair of ADCs it should >> be possible to evaluate the contribution of the Timepod itself to the noise >> floor. >> >> Using an interferometric technique with a Timepod allows a PN noise floor >> of -200dBc/Hz or less to be achieved (with a test source noise floor of >> around -175dBc/Hz or worse) when measuring the additive PN of components >> such as amplifiers. >> >> Bruce >> >> >> _______________________________________________ >> 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. _______________________________________________ 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.