A two-pass fixed point fast Fourier transform error analysis

A statistical model is used to predict the output signal-to-noise ratio (SNR) when a two-pass fast Fourier transform (FFT) is computed using fixed-point arithmetic. The results show that the ratio varies essentially as the square root of the number of points in the transform. Also included are the results of the simulation of a fixed-point machine and the variation of the error as a function of the length of the coefficients.