There are lots of tutorials about Fourier Transforms, Discrete Fourier Transform, and Fast Fourier Transform online... google found these for me: http://mathworld.wolfram.com/DiscreteFourierTransform.html http://ccrma.stanford.edu/~jos/mdft/mdft.html http://en.wikipedia.org/wiki/Discrete_Fourier_transform http://grus.berkeley.edu/~jrg/ngst/fft/fourier.html no homework...