Design of Decimation Filter With Improved Magnitude Characteristic and Low Complexity

Abstract

This paper presents a novel multiplierless decimation filter with low complexity, increased aliasing rejection, and a compensated passband. Simple multiplierless filters derived from symmetric polynomials, which introduce four additional zeros into certain comb folding bands, were introduced. As a result, the comb-folding bands are wider and provide improved aliasing rejection. Polyphase decomposition is applied to move this filtering to a low rate, thus decreasing the complexity expressed in the number of adders per output sample (APOS). The improvement in the passband characteristic is achieved with the compensator, which operates at a low rate. The compensator parameters were obtained using particle swarm optimization (PSO), and presented in a signed power of two (SPT) form to obtain a multiplierless design. The compensator design provides flexibility in the trade-off between the required number of adders and the quality of compensation. The superiority of the proposed filter is verified by comparison with the methods recently proposed in the literature, regarding complexity, aliasing attenuation, and passband compensation.