On the concept of time-frequency distributions based on complex-lag moments

The instantaneous frequency law is an important tool for the analysis of time-frequency content of a signal. Generally, the analyzed signals are composed of several time-frequency components characterized by various non-linear contents. To deal with the nonlinearity of time-frequency content, several time-frequency distributions have been proposed, mainly based on warping techniques. Recently, we introduced the time-frequency distributions based on complex-lag arguments. Its property to strongly reduce, in the case of a single component, the inner interferences due to the time-frequency non-linearity has been shown. In this paper we prove its capabilities to deal with multi-component signals. This property is achieved by an appropriate combination of complex-lag moments computed for different complex lags sets. Numerical examples prove the benefits of the concept defined in this paper.