Time-frequency methods are capable of analyzing and/or processing nonstationary signals and systems in an intuitively appealing and physically meaningful manner. This tutorial paper presents an overview of some time-frequency methods for the analysis and processing of nonstationary random signals, with emphasis placed on time-varying power spectra and techniques for signal estimation and detect...

Nonstationary oscillations are ubiquitous in music and speech, ranging from the fast transients in the attack of musical instruments and consonants to amplitude and frequency modulations in expressive variations present in vibrato and prosodic contours. Modeling nonstationary oscillations with sinusoids remains one of the most challenging problems in signal processing because the fit also depen...

Nonstationary chaotic behavior is not an oxymoron. We present two methods for capturing nonstationary chaos, then present a few examples including biological signals, ocean waves and traffic flow. The issue is of practical interest because it is often useful to capture when nonstationary events take place and it is desirable to know over what periods a signal is stationary.

The enhancement of speech degraded by nonstationary noises and low signal-to-noise ratio (SNR) conditions is a high demanding but challenging task. We present a robust and effective single channel speech enhancement algorithm under the framework of Nonnegative Matrix Factorization (NMF). Considering the sparse property of speech and low-rank property of nonstationary noise, a new formulation fo...