Redefinition of Fundamental Frequency

Abstract

Fundamental frequency of normal and esophageal utterances was measured by (1) number of pulses in a spectrographic continuous-amplitude display, (2) number of cycles in an oscillographic wavetracing, (3) harmonic interval in a narrow-band spectrogram. The results obtained by these measures yield widely varying fundamental frequencies. Moreover, narrow-band spectrograms often show two fundamental frequencies. In the case of two fundamental frequencies, the width of the harmonic interval in the high frequencies is one-half the width appearing in the low frequencies. Defining fundamental frequency in terms of (1) the number of pulse groups, rather than the number of pulses, and (2) the smallest harmonic interval, brings all three methods into agreement. The appearance of pulses in amplitude and/or time groups suggests that a single glottal cycle in some instances may be best defined as extending through more than one opening and closing of the glottis. (This research was supported by a grant from the National Institutes of Health.)