A prime factor FTT algorithm using distributed arithmetic

A time-efficient algorithm for calculating the discrete Fourier transform is developed. It uses a prime factor decomposition of the DFT into multiple short prime length DFT's which are converted into cyclic convolutions by an index permutation based on number theory. The convolutions are evaluated by table look-up using distributed arithmetic. When programmed on a Z80 microprocessor, the algorithm is 2-20 times faster than conventional algorithms. The approach also makes it possible to add simple external logic to a micro-processor system to further increase the speed.