Introduction - If you have any usage issues, please Google them yourself
Discrete Fourier transform calculation of a fast algorithm, referred to as FFT. Fast Fourier Transform in 1965 by JW Cooley and TW map out Kormakiti. This algorithm enables calculation of discrete Fourier transform computer required a significant reduction in the number of multiplication, in particular by changing the sampling points N more, FFT algorithm for calculating the amount of savings will be significant.