Integer FFT with Optimized Coefficient Sets

In this paper, the principle of finding the optimized coefficient set of integer fast Fourier transform (IntFFT) is introduced. IntFFT has been regarded as an approximation of original FFT since it utilizes lifting scheme (LS) and decomposes the complex multiplication of twiddle factor into three lifting steps. Based on the observation of the quantization loss model of lifting operations, we can select an optimized coefficient set and achieve better signal-to-quantization-noise ratio (SQNR). A mixed-radix 128-point FFT is used to compare the SQNR performance between IntFFT and other FFT implementations. A fixed-point simulation environment with the presence of additive white Gaussian noise (AWGN) channel is also constructed for comparison purposes.