Anders Time said the following on 01/25/2008 07:23 AM: > What is the best way to generate a very stable 10.001MHz(low E-13 or > -110dBc/1Hz) to be to do high resolution heterodyne(Allan deviation) > measurements? > Using DDS? > Using PTS 500 or 250 synth and divide? Using HP 8662A and divide? > Some smart pll circuit by locking the 1000Hz to the reference in some way? > Thanks > Anders
Rick Karlquist has published a design for a very low noise synthesizer designed for just this application. Unfortunately, I don't have a link to that handy, but it's on his website. I just took a look at some measurements I did on a PTS-250-SX51 (special version with low noise output to 25 MHz via an internal divider) and it looks like it would barely meet your requirements -- around 2x10e-13 at 1 second, and about -115 dBc/Hz at 1 Hz offset: http://www.febo.com/pages/pts_synth/images/pts-250-sx51-adev.png http://www.febo.com/pages/pts_synth/images/pts-250-sx51-spectrum.png However, that was at 10.000... MHz; the performance, particularly with respect to spurs, changes as the decimal dividers kick in for more complex frequencies. 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.