Filter banks with in band controlled aliasing applied to decomposition/reconstruction of ECG signals

This paper presents the realization of a pseudoQuadrature Mirror Filter (QMF) cosinemodulated filter bank with low amplitude distortion at the frequencies around ω=0 or ω=π, and high but controlled aliasing in specific bands. We obtain the analysis and synthesis filters as Spectral Factorization Approach, but the prototype is different because is a symmetric linear-phase filter. This filter bank is applied to the decomposition and reconstruction of an ECG signal. We propose some parameters appropriate to measure amplitude distortion and aliasing, and the reconstruction error in the output signal. 1. M-CHANNEL PARALLEL FILTER BANK An M-channel maximally-decimated parallel filter bank [1,2,3,4] (figure 1) consists of both analysis and synthesis filters. The analysis bank decompose an input signal [ ] n x into its subband components in order to use them in many applications as subband coding of audio and images. The synthesis bank reconstructs the M subband signals using filters ( ) z Fk . Figure 1: M-channel maximally decimated filter bank. The reconstructed signal [ ] n x̂ can be written as shown in (1), where M j M e W π 2 − = :