Adaptive tracking in the time-frequency plane and its application in causal real-time speech analysis

This paper proposes a causal approach to adaptive estimation of time-frequency localized signals using Adaptive Notch Filters (ANF). By adaptively estimating the envelope of each sinusoidal component, it is possible to specify the tracking quality and restart the ANF unit whenever the tracked sinusoid disappears, as well as preventing the ANF from ldquotrackingrdquo non-existent sinusoids (the frequency mis-lock situation). Employing multiple ANFs allows an efficient approach to tracking time-frequency localized signals such as speech.