NOVEL APPROACH TO SIGNAL MATCHED TWO CHANNEL MULTIRATE FILTER BANK USING NYQUIST FILTER

S.L. Nalbalwar,∗ S.D. Joshi,∗ and R.K. Patney∗

Keywords

Filter banks, estimation, half-band filter, signal representation, compression

Abstract

In this paper, we propose the novel approach to estimate the filters of 2-channel biorthogonal filter bank. In this approach, first FIR causal half-band filter from a given signal or its second statistics is estimated. By estimating the present sample, from the linear combination of samples which are at odd samples away from it, the coefficients of half-band filters are obtained. From the estimated half-band filter, by using spectral factorization, analysis and synthesis filters of the first channel are obtained. To obtain the filters of the second channel, of the 2-channel filter bank, theory of biorthogonal filter bank is used and the filters of second channel are obtained. It is observed that analysis and synthesis filters are found to be FIR. It is also observed that, using proposed approach, estimation of filter bank takes fewer computations as compared to other approaches reported in the literature. When this filter bank is used, in the context signal/image compression, it is found to give better results as compared to 2-channel standard biorthogonal filter bank. It is also seen that the average subband coding gain obtained in this case is higher than the 2-channel standard biorthogonal filter bank.

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