Various techniques have been developed to suppress fluctuations or noise in electronic signals. Specific object of the research presented in this volume is 1/f noise. A mystery for a long time since it was first observed by Johnson in 1925 in the low frequency part of the noise spectrum of an electric current passing a vacuum tube, this work shows that biological rhythm is basically subjected to 1/f fluctuations, perhaps more essentially than to stationary biological phenomena. Readers : biologists, natural scientists, engineers.
