A Novel Discrete Particle Swarm Optimization for FRM FIR Digital Filters

This paper presents a novel discrete particle swarm optimization (PSO) for frequency response masking (FRM) finite impulse response (FIR) digital filters over the canonical signed-digit (CSD) multiplier coefficient space. A look-up table (LUT) scheme is employed to ensure that the PSO automatically searches through permissible CSD multiplier coefficient values in the course of optimization without any recourse to backtracking. This is achieved by searching through the indices of the CSD multiplier coefficient values in the LUT instead of the coefficient values themselves. In this way, the resulting multiplier coefficient values are ensured to conform to a prespecified wordlength as well as to a prespecified maximum number of non-zero digits. The salient feature of this LUT scheme is that by introducing barren layers in the LUT, there is no need to limit the search space manually in the course of PSO to prevent from going over the boundaries of the search space. Examples are given to illustrate the application of the proposed PSO to the design and optimization of a lowpass and a bandpass FRM FIR digital filters.