Design of Optimal Stable Digital IIR Filters Using Hybrid Differential Evaluation

This paper proposes the innovative methodologies for the robust and stable design of infinite impulse response (IIR) digital filters using different mutation variants of differential evolution (DE). A multivariable optimization is employed as the design criterion to obtain the optimal stable digital IIR filter which satisfies the different performance requirements like minimizing the magnitude approximation error and minimizing the ripple magnitude in pass band and stop band. DE method is undertaken as a global search technique. Exploratory search is exploited as a local search technique. The proposed ten different mutation variants of DE method enhance the capability to explore and exploit the search space locally as well globally to obtain the optimal filter design parameters. The chance of starting with better solution is improved by comparing the opposite solution. Here both methods are effectively applied for the design of low-pass, and highpass digital IIR filters being multivariable optimization problems. The computational experimental results show that DE methods are superior or at least comparable to other algorithms and can be efficiently applied for higher order filter design.