Yes, I am wondering what sort of reference would be ten times better than a good OCXO at tau=0.1 second and stay good to tau=10^4 seconds. I am looking at the very first plot of http://www.leapsecond.com/pages/fury/. Also, what do you mean by " to avoid having to subtract background noise from the ADEV plot"? Is there a standard recipe for this type of operation? Thanks again, Javier
On Fri, Oct 17, 2008 at 11:17 AM, Tom Van Baak <[EMAIL PROTECTED]> wrote: > Hi Tom, >> I've been looking at some ADEV plots in your website, like >> the ones for the Fury, and I was wondering if there is a page >> in the site that explains your measurement setup. I am >> specifically interested in the reference oscillator you use. It >> should in principle be much better than the Fury's OCXO for >> short tau and better than GPS for medium tau, right? >> Thanks, >> Javier >> PS. Feel free to answer to the list. I was not sure I should post >> this since it's a direct question to you. >> > > Javier, > > That's a good question and it sort of depends on which year I > made the measurement or what performance level I'm expecting > out of the unit being tested. > > I also found out the hard way that it also depends on the tau, > since different references have different "sweet spots". Now > that I have quite a range of oscillators here, from BVA to ULN, > from cesium to maser, I can usually pick one that will give the > most accurate ADEV or PN plot for the range of tau that I'm > interested in. Not surprisingly I have no one standard that has > both the best PN and the best ADEV. For a lot of work I use > an unlocked Z3801A as the PN ref and a cesium or a locked > 58503B as the ADEV ref. But it varies according to need or > what's not in use at the moment. > > There's a good chance for any given plot that I have a record > here of which instrument generated the plot and what reference > was used. If it's important, either I mention it, or just ask me. > > On your GPSDO question, yes, to avoid having to subtract > background noise from the ADEV plot, one needs to use a > reference (and measurement system) that is several times, > maybe even 10x, better than what's being tested. > > /tvb > http://www.LeapSecond.com <http://www.leapsecond.com/> > > > _______________________________________________ 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.
