If you want a more intuitive feel for what the FFT *does* (not just "do this math to the signal; the resulting output means..."), may I suggest (disclosure: My article, pretty old, would benefit from being more interactive or a video—maybe some day I'll get to it):se729 wrote:I'm on to FFT now, it's a quagmire, the first decomposition type that has the potential to make the student decompose.
http://www.earlevel.com/main/2002/08/31 ... o-the-fft/
