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

[jimlux]

On 2/8/11 6:32 AM, Mark Kahrs wrote:
> The Goertzel algorithm is only useful when you want a few frequences
> (i.e., it evaluates specific frequencies on the unit circle).  For
> general all purpose slicing and dicing, the FFT is what you want.  See
> the ancient book by Rabiner for the details.
>

The Chirp-z transform (Bluestein) is also useful when you want a small 
range of frequencies at higher resolution, but since it relies on a fast 
convolution of the whole data set, it's more computationally intensive 
than a straight FFT.

I ran across a nice explanation of how it works and why it's useful the 
other day
http://www.katjaas.nl/chirpZ/chirpZ.html

(if you want some ancient FORTRAN IV code for this, I've probably got a 
listing in a box out in the garage from the 70s)