Design of FRM-based MDFT filter banks in the canonic signed digit space using modified meta-heuristic algorithms

Abstract

An optimal totally multiplier-less sharp transition width Modified Discrete Fourier Transform (MDFT) filter bank is proposed in this work. Since, here, the aim is to design a low complexity sharp transition width MDFT filter bank, the filters of the filter bank are designed using Frequency Response Masking technique to reduce the number of multipliers and hence the complexity. To replace multipliers with adders and shifters, the filter coefficients are converted into the Canonic Signed Digit space. In order to reduce the number of adders and shifters in the multiplier-less implementation, restricted number of non-zero bits is used in the conversion. This may degrade the performances of the MDFT filter bank. The performances are improved using modified meta-heuristic algorithms. A new hybrid algorithm which combines the qualities of Harmony Search Algorithm and Gravitational Search Algorithm is proposed in this work to optimise the performance of the MDFT filter bank.