Multi-component FM demodulation of speech based on the short time Fourier transform (STFT) phase

摘要

Speech is a signal which is produced as a combination of frication and a quasi periodic train of glottal pulses excites the vocal tract and causes it to resonate. Information is encoded on the signal as the vocal tract changes configuration, resulting in a rapid change of the resonant frequencies. We develop methods, based on differentiation of the short time Fourier transform (STFT) phase, which effectively demodulates the speech signal and produces accurate, high resolution time-frequency estimates of both the resonances and the signal excitation. The method effectively condenses the STFT surface along curves representing the instantaneous frequencies of the vocal tract resonances and the channel group delay function.