EFFECTS OF BANDWIDTH ON GLOTTAL AIR-FLOW WAVE-FORMS ESTIMATED BY INVERSE FILTERING

The aim of this research was to examine the effect of the bandwidth on parameters that are used to quantify glottal airflow waveforms that h ave been obtained by inverse filtering the acoustic signals. Three ban dwidths (1, 2, and 4 kHz) were compared using /a/ vowels of different phonation types. Glottal waveforms were characterized using three rati os computed from the flow (open quotient, speed quotient, and closing quotient) and two parameters extracted from the differentiated flow (t he amplitude of the negative peak and the return time from the negativ e peak to zero level). The results show that especially in pressed pho nation the bandwidth should be at least 4 kHz. Distortion caused by an insufficient frequency range was most severe in the parameters extrac ted from the flow derivatives. Among the parameters computed from the flow signals, the closing quotient was affected most when the bandwidt h was reduced. (C) 1995 Acoustical Society of America.