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.