Efficiently VLSI-realizable prototype filters for modulated filter banks

FILTER BANKS Tanja Karp Hamburg Univ. of Technology Telecommunications Institute 21071 Hamburg, Germany [email protected] Alfred Mertins University of Kiel Kaiserstr. 2 24143 Kiel, Germany [email protected] Truong Q. Nguyen Univ. of Wisconsin, ECE Dept. 1415 Engr. Dr Madison, WI 53706, USA [email protected] ABSTRACT This paper presents methods for the e cient realization of prototype lters for modulated lter banks. The implementation is based on the lattice structure of the polyphase lters. The lattice coe cients, representing rotations, are approximated by a small number of simple -rotations each of which can be realized by some shift and add operations instead of a multiplication. Since the lattice structure is robust against coe cient quantization we do not loose the perfect reconstruction (PR) property of the lter bank when doing this approximation. Frequency responses of the original and approximated prototype lters are compared in terms of complexity and stopband attenuation.