[time-nuts] Calculate spectral content from a series of zerocrossing time stamps?

[ehydra]

SpectrumLab uses the Goertzel-Algorithm to trim the time reference to 
the millisecond range. Maybe that is comparable and as algoritm 
transverable?

- Henry


J. L. Trantham schrieb:
> DFT?  Direct Fourier Transform?
> 
> Thanks,
> 
> Joe
> 
> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
> Behalf Of Tijd Dingen
> Sent: Monday, February 07, 2011 9:02 PM
> To: time-nuts at febo.com
> Subject: [time-nuts] Calculate spectral content from a series of
> zerocrossing time stamps?
> 
> 
> 
> 
> Consider the following scenario. We have a signal source of about 10 kHz,
> with unknown phase noise. Let's for simplicity's sake assume for now that
> the phase noise is large enough that it will be detectable by the following
> approach.
> 
> We measure every zero crossing with lets say 1 ns accuracy. So we have a
> signal with a nominal period of 100 us, and we can measure every zero
> crossing to within 1 ns. This gives you ~ 10,000 data points every second.
> 
> Now how does one efficiently calculate the spectral content based on these
> 10,0000 zero crossings? The end result would be the spectral density,
> centered around that nominal 10 kHz frequency.
> 
>>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.
> 
> This is a nice enough approach, but you pay a computational price for the
> fact that this algorithm is able to handle more generic inputs than is
> needed in this particular case. So possibly there is a more efficient
> method, only which one?