A novel variable-filter band discrete wavelet transform and its application on fetal electrocardiogram

It is well known that a mother wavelet for the discrete wavelet transform (DWT) has the band-pass filter characteristic with octave width in the frequency domain and can be used for octave analysis. However, it is possible that the octave analysis is not necessarily the most suitable to match the analysis signal. In this study, a novel variable-filter band discrete wavelet transform (VFB-DWT) is proposed. It is achieved by using variable-band filters instead of conventional decomposition and reconstruction sequences, which are designed in consideration of the real signal characteristics. Furthermore, the VFB-DWT is applied to the fetal electrocardiogram de-noising and good performance has ben obtained.