ADAPTIVE SHORT-TIME FOURIER-ANALYSIS

This letter presents a method of adaptively adjusting the window lengt h used in short-time Fourier analysis, related to our earlier work in which we developed a means of adaptively optimizing the performance of the cone kernel distribution (CKD). The optimal CKD cone length is, b y definition, a measure of the interval over which the signal has cons tant or slowly changing frequency structure. This letter shows that th is length can also be used to compute a time-varying short-time Fourie r transform (STFT). The resulting adaptive STFT shares many desirable properties with the adaptive CKD, such as the ability to adapt to tran sient as well as long-term signal components. The optimization require s O(N) operations per step, less than the fast Fourier transform (FFT) used in computing each time slice, making it competitive in complexit y with nonadaptive time-frequency algorithms.