A novel technique for the design and DCGA optimization of bilinear-LDI lattice-based digital IF filters

Abstract

Intermediate Frequency (IF) filters find diverse practical applications in modern communication systems. This paper presents a novel technique for the design and optimization of digital IF filters. This technique consists of two separate stages. In the first stage, the bilinear-LDI lattice digital filter realization approach is exploited and applied to the design of an infiniteprecision digital IF filter responsible for satisfying the given design specifications only approximately. In the second stage, a diversity-controlled (DC) genetic algorithm (GA) is applied to the finite-precision optimization of the resulting IF digital filter so as to satisfy all the design specifications exactly. The DCGA optimization employs an existing cross-generational probabilistic survival selection scheme for increasing the convergence speed. The application of the proposed technique to the optimization of an eighteenth-order AMPS digital IF filter operating around a center frequency of 455 kHz only required 500 generations to converge.