Efficiently VLSI-realizable prototype filters for modulated filter banks

This paper presents methods for the efficient realization of prototype filters for modulated filter banks. The implementation is based on the lattice structure of the polyphase filters. The lattice coefficients, representing rotations, are approximated by a small number of simple μ-rotations each of which can be realized by some shift and add operations instead of a multiplication. Since the lattice structure is robust against coefficient quantization we do not loose the perfect reconstruction (PR) property of the filter bank when doing this approximation. Frequency responses of the original and approximated prototype filters are compared in terms of complexity and stopband attenuation.