Structures for digital filter banks

Signal processing structures, incorporating one and two digital filter banks (DFB´s), are examined with the aid of a polyphase transform that is defined. Convenient matrix descriptions for DFB structures and the short-time Fourier transform are obtained. A condition for decimation in DFB´s without aliasing is obtained and shown to be equivalent to shift invariance. Certain commonly employed filter banks with real and complex structures age seen to admit realization with the low noise, memory efficient SIDO filter structure.