Interference-Aware Instantaneous Frequency and Amplitude Estimator for Multicomponent Signals

In this paper, we introduce a novel instantaneous frequency (IF) estimator for multicomponent signals (MCSs), that takes into account the potential presence of interference in the time-frequency (TF) plane. Our approach optimizes the spectrogram window locally in the TF domain to enhance signal representation, adapting to isolated or interfering modes. This optimization leads to the definition of candidate IF points, which are then gathered together using a novel ridge detection approach, and, finally, IF estimates are obtained by adapting a spline fitting procedure to the potential presence of crossing modes. An extra benefit of the proposed technique is that it also gives access to estimates of the instantaneous amplitudes of the modes, and thus to that of the ideal TF signature of the signal. The proposed IF estimation method compares favorably with state-of-the-art techniques especially on MCSs containing modes with very different frequency modulation.