, Islamic Azad University, Qazvin Branch
There are two types of digital filters including Infinite Impulse Response (IIR) and Finite Impulse Response (FIR). IIR filters attract more attention as they can decrease the filter order significantly compared to FIR filters. Owing to multi-modal error surface, simple powerful optimization techniques should be utilized in designing IIR digital filters to avoid local minimum. Imperialist competitive algorithm is an evolutionary algorithm used in solving optimization problems in recent years. It can find global optimum response in a nonlinear searching space. In this paper, performance of chaotic orthogonal imperialist competitive algorithm has been improved through some variations in it. Then, this modified algorithm has been applied in designing IIR digital filters and their performance has been compared to some evolutionary algorithms.