Comparison of two methods for realization of multiplierless elliptic IIR filters

Two methods for multiplierless elliptic IIR filter implementation are discussed: cascade realization and parallel connection of two allpass networks. Elliptic IIR filters are selected because they fulfill the requirements with lower order, and, usually, they require fewer coefficient multipliers. The comparison is made on the basis of adder costs, amplitude characteristics in pass and stop bands, coefficient wordlength and normalized product round-off noise variance at the output of the filter. This paper concentrates on the fixed-point arithmetic. The comparison between these different design algorithms for digital multiplierless IIR filters has not yet been reported. In this paper that comparison has been made for the first time. It is very important to point out that different designs have been compared under the same conditions.