FFT computation is less complex as compared to the DFT algorithm.
DFT Transform
FFT Transform
Fig: FFT Transform of 8 Point DFT
In the above figure, it is shown that the basic idea of a fast Fourier transform is to
break up a transform of length N into two transforms of length N/2.
To compute the DFT of an N-point sequence it take O(N2) multiplies and adds. The FFT algorithm computes the DFT using O(N log N) multiplies and adds.
The fast Fourier transform (FFT) is a discrete Fourier transform algorithm which reduces the number of computations needed for N points from 2N2 to 2Nlog2N.
.png)
.png)