Design of Multiplierless IFIR based Cosine Modulated Filter Bank using QPSO

This paper presents an improved technique for designing nearly perfect cosine modulated multiplierless filterbank, based on interpolated finite impulse response filter (IFIR) and quantum behaved particle swarm optimization (QPSO). In this technique, the filter coefficients are represented within canonical signed digit (CSD) space to minimize multipliers. An adjustable window approach is used to build a sample filter, i.e. IFIR, and then by using quantum behaved particle swarm optimization (QPSO), the quantized coefficients are optimized to achieve magnitude response of 0.707 at cutoff frequency, by changing cut off frequency of the model filter. Hardware complexity in terms of adders is reduced by CSD, which is a form of sign power of two terms and aids in implementing multipliers in terms of adders and shifters. Experimental analysis of benchmark design examples has been included to determine the effectiveness of proposed method by evaluating quality measurement parameters such as reconstruction error, aliasing error, number of adders in the sign power of two terms (SPT) representation and canonic signed digit representation.