Higher harmonics and formants analysis of speech signals

Spectral analysis of windowed segments (12.8–52.8 ms in duration), of the approximately steady portion of vowel sounds, in the context CVC, was analyzed for several individuals at various SPL levels for each subject. It was observed that the signals with larger SPL values were much richer in harmonics and formants. A relation between the straining of the vocal cords and the higher harmonics is established and its relation with nonlinear models of the vocal chords and vocal tract examined. The higher harmonics of the fundamental frequency, sixth and above, and the higher order formants, third and above, when present for certain vowel sounds, may be of particular importance as diagnostic tools in vocal-fold-vocal-tract clinical examination.