Order of N complexity transform domain adaptive filters

Abstract

Implementation of the transform domain adaptive filters is addressed. Recent results [11] [14] have shown that if the input data to a radix-2 fast Fourier transform (FFT) structure is sliding one sample at a time, only N - 1 butterflies need to be calculated for updating the FFT structure, after the arrival of every new data sample. This is opposed to most of the previous reports that assume order of N log N complexity, for such implementation. In this paper the sliding implementation of the other useful transforms, that can also be implemented with the order of N complexity, are worked out in detail.