A New Class of High Performance FFTs

FPGA implementations of block floating point (BFP), streaming, 256-point and 1024-point fast Fourier transform (FFT) circuits are described as examples of a new architectural approach that provides better performance, flexibility, and functionality than commercially available pipelined FFTs. It is based on a matrix formulation of the discreet Fourier transform (DFT) that converts the direct transform into structured sets of arithmetically simple 4-point transforms that are computed on a systolic array. This circuit architecture permits transform lengths that are not a power-of-two, can do 2-D as well as 1-D transforms, is scalable, has low computational latency and utilizes BFP and floating point (FP) features to provide high dynamic range. Circuit comparisons are made with a commercially available pipelined FFT.