Title: Design of multiplier-less continuously variable bandwidth sharp FIR filters using modified harmony search algorithm
Authors: James T. George; Elizabeth Elias
Addresses: Department of Electronics and Communication Engineering, National Institute of Technology Calicut, Kerala, 673601, India ' Department of Electronics and Communication Engineering, National Institute of Technology Calicut, Kerala, 673601, India
Abstract: Variable bandwidth filters (VBFs) which are widely used in applications such as SDR channelisers, require online tuning of the frequency characteristics, re-configurability and low complexity. Conventional methods require some mathematical computation to obtain the new filter coefficients for each desired bandwidth. Harris (2009) has proposed a new design method for a variable bandwidth filter without change in the filter coefficient values. But this can be used only for bandwidth reduction. George and Elias (2012) have proposed a design method for bandwidth reduction as well as enhancement. This paper proposes an optimal and totally multiplier-less implementation of a VBF. A frequency response masking filter with continuous coefficients is designed and synthesised in the canonic signed digit (CSD) format. Metaheuristic optimisation algorithms such as differential evolution and harmony search are deployed to determine the optimised filter coefficient values and the system performances in the bandwidth reduction and enhancement cases are evaluated.
Keywords: variable bandwidth filters; VBF; frequency response masking; finite impulse response; FIR filters; re-sampling; differential evolution; harmony search; canonic signed digit; CSD; multiplier-less; filter design.
International Journal of Information Technology and Management, 2015 Vol.14 No.1, pp.5 - 25
Received: 16 Jan 2013
Accepted: 13 May 2013
Published online: 30 Nov 2014 *