Originally published in French as Temps-frequence, this book is a multi-disciplinary introduction to the toos of time-frequency signal analysis (often referred to as wavelet analysis). It serves as an invaluable reference for anyone concerned with the application of these techniques to signal processing.

Although Fourier analysis provides a natural environment for the description of stationary signals, most real signals are nonstationary. Indeed, most often an integral part of the information contained in a signal can be found in the nonstationary property itself (e.g., start and termination of events, drifts, ruptures, modulations). This book provides a coherent and self-contained presentation of a broad panorama of methods for analyzing nonstationary signals, an area which has recently undergone intensive development in signal processing. Special emphasis is given to non-parametric approaches, with particular focus on quadratic energy distributions. This book offers a discussion of problems that emerge from a mixed description in time and frequency, and it comprises a detailed construction of the principle classes of admissible solutions (short-time Fourier, wavelets, Wigner-Ville, Cohen's class, affine distributions, etc.). It also addresses numerous issues of interpretation related to such representations and shows how to reformulate several important problems in signa theory by utilizing joint time-frequency distributions.