Truly nonstationary techniques for the analysis and display of voiced speech

The assumption of quasi-stationarity in the analysis of speech is questioned from the standpoint of the best resolution of global periodicity and vocal tract formant frequency locations. The generalized class of time-frequency representations is discussed from the standpoint of speech analysis and is integrated with a description of the spectrogram. The spectrogram is known to have minimal interference artifacts, and the truly nonstationary cone-kernel time-frequency representation (CK-TFR) is shown to be similarly free of interference. The CK-TFR is observed to give higher resolution of the time point of glottal closure, and the clarity of some formant frequencies, especially for a nasal consonant, is shown to be better than the spectrogram. It is shown that interference-free representations of speech with a higher simultaneous resolution in time and frequency than the spectrogram are possible, and that these new representations may be applicable to the better analysis and understanding of speech