Analysis-Synthesis of Glottal Excitation

A high-speed motion picture was used to obtain the time-dependent glottal opening for a speaker phonating /a/. The pressure waveform measured by a microphone at the speaker's lips was also recorded on film simultaneously with the glottal opening. A digital computer with a scope and light-pen facility was used to extract the glottal area and pressure waveform on a frame by frame basis. Van den Berg's relation for the resistance of the glottis to steady air flow was then used to calculate the time-dependent glottal volume velocity. The volume velocity was then used to excite a POVO. The output from the POVO was compared with the pressure waveform recorded during phonation. Volume velocities calculated for different subglottal pressures and a “standard” triangular waveform were also used to excite the POVO. Psychoacoustic evaluations were made of the natural quality of the various synthesized outputs.