Pitch Synchronous Spectral Analysis of Vowel Sounds
Joan E. Miller, M. V. Mathews, Edward E. David · The Journal of the Acoustical Society of America · 1959
Fourier analysis of individual periods of sustained vowel sounds has been carried out on a digital computer. The spectral data show two characteristics (1) a periodic oscillation in amplitude and (2) many rapid phase shifts, which cannot be explained by simple vocal tract resonances. A theory is developed to show that these spectral characteristics can be attributed to zeros of the glottal excitation function and that typically there is a large number of these zeros. Such a representation of the excitation is consistant with the glottal wave-form information from high-speed photography. A computer program has been developed to fit a spectrum with a pole-zero configuration and good agreement has been obtained between the observed spectrum and that computed from a pattern of glottal zeros and formant poles.