Hi, Wavecrest uses algorithms for this and their software gives a spectrum. They also give some info on their site.
Henk Op 8 feb 2011, om 20:51 heeft [email protected] het volgende geschreven: > 08.02.2011 08:17, Poul-Henning Kamp: >> In message <[email protected]>, Tijd Dingen >> writes: >> >>>> 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. > > As far as I know a bandpass signal is described uniquely by its zero > crossings to within a constant. That is due to the Weierstrass > factorization theorem. A more practical foundation is outlined in > "B.F.Logan: 'Information in the zero crossings of bandpass signals', The > Bell System Technical Journal vol. 56 Number 4, April 1977" and some > other publications by the same author in the same journal. > > Recently these techniques have been exploited in 'zepoc' algorithms for > low power hifi class D amplifiers and the 'click modulation' scheme. > > But there were also publications which were in doubt that a real valued > signal can be reconstructed by its zero crossings. > > Sadly, my mathematical background is not sufficient to follow the > arguments. But nonetheless zero crossing algorithms and nonuniform > sampling are very promising fields. > > Cheers > Detlef > > _______________________________________________ > 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. _______________________________________________ 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.
