I know of a DOS program which did this, but I wouldn't know where to find this nowadays, let alone that you can run a DOS program on 'modern' machines without some serious virtualisation :-). (... Oh wait,
here it is. I remembered the author mentioning it being used for studying whale migration data, and then Google can easily find it...) You'll be wanting a software library which does the so-called
fast fourier transform or FFT: there are a few available on Aminet. The FFT generates exactly the same result as a normal FT; the 'fast' stems from the fact that it is a
much faster algorithm.
If you want to code the Fourier transform yourself, then start with the 'slow' algorithm as it is easier to grok by far. For small samples to transform, the difference in execution time isn't really noticable, and the fast algorithm requires a few arcane bookkeeping tricks to make it fast in practice, too.
