Wavelet Analysis And Its Applications To Speech Signal

Wavelet analysis is a newly developed theory, which overcomes the disadvantages of traditional Fourier analysis. It has good localized features in both the time domain and the frequency domain and has important application value in the fields of signal processing, image processing, speech analysis and so on. This paper describes in detail the basic knowledge of wavelet theory, studies the application of wavelet analysis to speech signal processing and presents a new method for the speech signal envelop extraction based on the complex analytical wavelet transform which overcomes the disadvantages of the traditional Hilbert transform in extracting signal envelop. This paper also describes a frequency bands division of the speech signal by combining the wavelet transform and wavelet packet transform. This division method is similar to the critical bands of human being ear. On the basis of this, the paper puts forwBrd a low bit rate speech coding algorithm in combination with the bit allocation technology. This algorithm is characterized by wide application area, good sound quality, no man-made noise etc. This paper finally studies the methods for embedding digital watermarking in digital speech signal. By making using of the advantages of wavelet transform in signal processing, the paper provides a digital watermarking embedded and detect algorithm. The tiny difference is nelectable by human ear. Simulation results were given to show this method is simple, less complexity and has strong robustness towards various signal processing.