Pitch of Periodic Pulses without Fundamental Component

Abstract

The pitch of a periodic pulse train is matched to that of another train whose fundamental component of frequency is rejected. Three modes of pitch perception are found. The first obtains for pulse rates less than 100 pps. Here, in a manner similar to that found previously for unfiltered stimuli, the pitches are matched to equate pulse rate, regardless of the polarity patterns of the trains. The second mode occurs for fundamental frequencies in the approximate range 200–500 cps. Here there is a decided tendency to equate fundamental frequencies. The third mode is manifested for fundamental frequencies of the order of 1000 cps and higher. In this range subjects tend to equate the fundamental of the matching tone to the lowest spectral component present in the matched stimulus. Between the modes, transition regions exist in which the pitch assignment generally is difficult and uncertain. The stimuli are studied with an electrical analog of the basilar membrane. Waveforms of membrane displacement and first spatial derivative of displacement are obtained from the analog. The three (psychophysical) pitch modes are found to be manifested in these mechanical functions of the basilar membrane.