A polyphase and FFT realization of modulation sub-band adaptive filter with minimum sampling rate

In this paper, a polyphase and FFT realization of a sub-band adaptive filter is proposed. In the polyphase and FFT realization for the transmultiplexer, the sampling rate reduction is the same as the number of the sub-bands. In the proposed method, however, they are different, so the conventional method cannot be applied. In the new realization, the polyphase filters are divided into a tapped delay line and an FFT part so as to be shared by all the sub-bands. Computational complexity is well reduced compared with the direct realization