Entropy-based Time-Varying Window Width Selection for Nonlinear type Time-Frequency Analysis

TL;DR

This paper introduces a novel time-varying window width selection method to enhance nonlinear time-frequency analysis techniques, especially for signals with rapidly changing frequencies, demonstrated through synthetic and physical data.

Contribution

The proposed TVOWW scheme adaptively optimizes window width for improved time-frequency representations in nonlinear analysis methods.

Findings

Enhanced concentration in time-frequency representations.

Effective for signals with fast-varying frequencies.

Validated on synthetic and attosecond physics data.

Abstract

We propose a time-varying optimal window width (TVOWW) selection scheme to optimize the performance of several nonlinear-type time-frequency analyses, including the reassignment method, and the synchrosqueezing transform (SST) and its variations. A window rendering the most concentrated distribution in the time-frequency representation (TFR) is regarded as the optimal window. The TVOWW selection scheme is particularly useful for signals that comprise fast-varying instantaneous frequencies and small spectral gaps. To demonstrate the efficacy of the method, in addition to analyzing a synthetic signal, we study an atomic time-varying dipole moment driven by two-color mid-infrared laser fields in attosecond physics.