Order of N complexity transform domain adaptive filters

Implementation of the transform domain adaptive filters is addressed. Recent results 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. This is opposed to most of the previous reports that assume order of NlogN complexity for such implementation. In this correspondence, a generalization of the sliding FFT, which introduces a wide class of orthogonal transforms that can be implemented with the order of N complexity is proposed.<
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