The analysis of signals is discussed from a general point of view and the importance of physical energy in the process represented by the signal noted. This approach is motivated by a careful analysis of the speech production process and is discussed with reference to the modeling of the speech wave. An especially simple nonlinear operator, Teager's energy operator, is defined in both the continuous and discrete domains and shown to be a very useful ``tool'' for analyzing single component signals from this energy point-of-view. Several important properties of these operators are shown that make it possible to determine the energy functions of quite complicated functions provided these functions can be expressed as products of simpler functions, this operation of function multiplication being typical of a modulation process. It is shown how the energy operator may be used to extract both the amplitude modulation and the frequency modulation from a combined AM-FM signal. A number of examples are given.

Dr. Kaiser is currently a Visiting Professor at Duke University, Durham, NC and at Rutgers University in Piscataway, NJ. He was formerly a Distinguished Member of Technical Staff in the Speech and Image Processing Research Division of Bell Communications Research, Inc. where he had been since 1984. Prior to that he was a Distinguished Member of Technical Staff at Bell Laboratories, Murray Hill, New Jersey for 25 years where he worked in the areas of speech processing, system simulation, digital signal processing, computer graphics, and computer-aided design. He received his EE degree from the University of Cincinnati in 1952 and his SM and ScD degrees from MIT in 1954 and 1959, where he also taught for three years.

Dr. Kaiser is a Fellow of the IEEE and AAAS, a registered engineer in Massachusetts, a member of the ASA, EURASIP, and SIAM societies. He is a member of the honor societies Sigma Xi, Tau Beta Pi, and Eta Kappa Nu.