Abstract:

A directional S transform is proposed to estimate the instantaneous frequency of multicomponent frequency modulated signals. High performance is achieved by three stages. Firstly, to resolve the low frequency resolution on the time frequency plane at high frequency, a varying tendency window is introduced into the S transform. Secondly, in order to achieve the directional matching of the complex frequencymodulated(FM) signals on the time frequency(TF) plane, the directional S transform is presented by incorporating directional parameter and maximal rule. Finally, since the TF ridge and the corresponding mean square errors will be invalid under multicomponents conditions, a confidence criterion of auto term region is also proposed. The effectiveness of the presented method is verified by the mixture of linear and nonlinear FM signals.