A novel Nth-order IIR filter-based graphic equalizer optimized through genetic algorithm for computing filter order

Equalizers play an essential role in processing and enhancement of quality of audio signals apart from their conventional utilizations to flatten out undesirable harmonics from telephone signals, music, etc. In recent times, research in different variants of equalizers has seen a great increase with optimization algorithms trying to provide maximum gain with least interference between adjacent frequency bands. This research paper proposes a 16-order IIR bi-quad filter optimized with evolutionary algorithm in the form of genetic crossover and mutation to provide maximum gain. The magnitude, frequency response and group delay characteristics obtained from the proposed algorithm have been tested and analyzed by comparing with existing conventional Nth-order IIR implementations without optimization and superior performance observed. It could be seen that that peak error oscillates between ± 1.9 dB for hundredfold increase in order of filters with a maximum limit set at 750. Computational complexity is observed to be reduced as the proposed algorithm searches the sample space for the best order suitable for the given target output in the least time possible. The experimentations have been implemented in MATLAB and SNRs measured as performance metric.

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