> > From what I could find so far, one method to go about this is use a > > Lomb/Scargle Periodogram. And specifically the method by Press & Rybicki > > that extirpolates the unevenly timed samples to an regular timed mesh, > > after which a regular DFT is done.
> Just knowing the time of the zero-crossings is very little information > to go by, but you have to make some kind of assumption about the > perfection of curve shape between those points, in order to say > anything meaningful. Correct. And for now the working assumption is that the input signal is sinusoidal, with just a smattering of noise. > The dirty but not necessarily quick way to analyze the data, is to > turn it into a +/- 1 squarewave at 1GHz (1/1ns), low-pass filter > it with a 15-18 kHz cut-off and do the usual FFT. Yeah, I thought of that one. But it becomes prohibitive in terms of resources real fast. ;) > The other option is to normalize your zero-crossings, so you get > signed numbers telling how early/late they happen, and do a FFT > on that. Its too early in the morning for me to be able to see > how you transform the resulting phase-deviation spectrum to a > normal frequency offset plot, but a few tests with synthetic data > should tell you that. There's an idea. I will be doing a curve fit of the time stamps anyway, so I get the time deviations from the fit for "free". Normalize the time deviations into phase deviations, and use that. Worth a try, thanks! Fred _______________________________________________ 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.
