IF Estimation for Multicomponent Signals

Abstract

Concurrent IF estimation of the separate components of a multicomponent FM signal using TFD peaks location requires conditions on the selection of a suitable quadratic TFD. Required properties are: (1) high time-frequency resolution while suppressing cross-terms efficiently, (2) the TFD to enable direct amplitude estima- tion for the individual components, (3) the variance of the IF estimate using the TFD should be a continuously decreasing function of the lag window length while the bias is continuously increasing. Quadratic time-frequency distributions that satisfy these conditions were presented and discussed. A constant-window tracking algorithm may not give a robust IF estimate if the IF changes rapidly with time due to the effect of the higher-order derivatives of the IF law. Hence an adaptive algorithm is used for robust multicomponent IF estimation.