An architecture for a radix-4 modular pipeline fast Fourier transform

We present a radix-4 modular pipeline architecture for computing the discrete Fourier transform (DFT). For an N-point DFT, two conventional pipeline √N-point fast Fourier transform (FFT) modules are joined by a specialized center element. The center element contains memories, coefficient ROMs, multipliers, and control logic. Compared with a standard N-point pipeline FFT, the modular FFT significantly reduces the number of delay lines to 2√N. Further, the coefficient storage is concentrated within the center element, thereby reducing the ROM requirement within the pipeline FFT modules. The centralized memory and address generator provide data storage and reordering. The architecture has been analyzed through simulation and compared to the conventional pipeline FFT. The throughput of a standard radix-4 pipeline FFT is maintained with a slightly higher end-to-end latency. A reduction in power is achieved because the modular pipeline exhibits N/2 bit transitions on each clock as compared to y bit transitions in the conventional pipeline.