Instantaneous frequency estimation and measurement: a quasi-local method

This paper describes a method for estimating the instantaneous frequency and instantaneous amplitude of real signals. The method is based on engineering ideas and uses frequency separation with a filter similar to those found in radio devices. The method approximates the analytic signal, and the estimated amplitude and frequency are practically the same as those given by the analytic signal. The method is simple, fast, precise, robust to noise, easy to implement, free of parasitic cross-terms and gives results which compare very favourably with other methods for the measurement of frequency modulated signals, associated or not with amplitude modulation. Examples are given, both of mathematical signals and of real world signals (a bat echo-location signal), showing that the method can be used for precise analysis of a very large variety of signals.