Nonrecursive digital filtering using cascade fast Fourier transformers
Gerald C. O'Leary · IEEE Transactions on Audio and Electroacoustics · 1970
The organization of a special-purpose digital processor for performing nonrecursive digital filtering is described. The processor uses two complementary cascade fast Fourier transformers. Each transformer can simultaneously transform two independent data blocks of lengthNwords using\log_{2} Narithmetic units and3/2 Ncomplex words of digital storage. Continuous filtering is achieved by sectioning the input signal, performing a fast transform on each section, multiplying by the frequency characteristics of the desired filter, and inverse transforming. The cascade organization of the processor allows processing at very high speeds. Word rates in excess of 3 MHz are possible with currently available hardware.