A sparing SC filter design approach with reduced transmission zeros

摘要

A systematic switched-capacitor (SC) filter design method that satisfies a set of frequency specifications while its implementation requires less total capacitance than the conventional design using the bilinear mapping is presented. The design approach is based on: (i) a prewarping scheme for different mappings of the 1/s and 1/s/sup 2/ terms of each biquadratic factor forming the transfer function; (ii) strategic addition of zeros at z=-1; and (iii) iterative modification of the frequency responses rendering different transfer functions that eventually satisfy the original frequency design specifications. A detailed algorithm is discussed together with an examples showing the attractive properties of the proposed method.