This book can serve as a textbook on the theory of wavelets and their applications in the MATLAB system. It is available to students of higher education institutions specializing in mathematics and engineering sciences, and will be useful to those skilled practitioners using wavelets in their work. The book includes information on Fourier series and Fourier transform, a discrete Fourier transform, filters and signal degradation. In addition to presentation based on wavelet theory also describes the main functions of the wavelet analysis in MATLAB system.