1. Large number of the applications such as filtering, correlation analysis, spectrum analysis require calculation of DFT. But direct computation of DFT require large number of computations and hence processor remain busy. Hence special algorithms are developed to compute DFT quickly called as Fast Fourier algorithms (FFT).

2. The radix-2 FFT algorithms are based on divide and conquer approach. In this method, the N-point DFT is successively decomposed into smaller DFT‘s. Because of this decomposition, the number of computations are reduced.

Radix-2 Fft Algorithms

1. DECIMATION IN TIME (DITFFT)