Research ArticleCat Swarm Optimization algorithm for optimal linear phase FIR filter design

- A novel algorithm called Cat Swarm Optimization (CSO) algorithm is adopted in this paper.
- CSO algorithm is applied for the solution of the constrained, multi-modal optimal FIR filter design problems.
- It is shown that CSO converges very fast to the best quality optimal solution with the least execution times.
- CSO demonstrates the best performance in terms of magnitude responses, the minimum stop band ripple, highest stop band attenuations.
- The CSO is a good global optimizer for obtaining the optimal filter coefficients of digital filter design problem.

In this paper a new meta-heuristic search method, called Cat Swarm Optimization (CSO) algorithm is applied to determine the best optimal impulse response coefficients of FIR low pass, high pass, band pass and band stop filters, trying to meet the respective ideal frequency response characteristics. CSO is generated by observing the behaviour of cats and composed of two sub-models. In CSO, one can decide how many cats are used in the iteration. Every cat has its′ own position composed of M dimensions, velocities for each dimension, a fitness value which represents the accommodation of the cat to the fitness function, and a flag to identify whether the cat is in seeking mode or tracing mode. The final solution would be the best position of one of the cats. CSO keeps the best solution until it reaches the end of the iteration. The results of the proposed CSO based approach have been compared to those of other well-known optimization methods such as Real Coded Genetic Algorithm (RGA), standard Particle Swarm Optimization (PSO) and Differential Evolution (DE). The CSO based results confirm the superiority of the proposed CSO for solving FIR filter design problems. The performances of the CSO based designed FIR filters have proven to be superior as compared to those obtained by RGA, conventional PSO and DE. The simulation results also demonstrate that the CSO is the best optimizer among other relevant techniques, not only in the convergence speed but also in the optimal performances of the designed filters.