Pitch Perception of Pulse Pairs with Random Repetition Rate

Abstract

Time-separation pitch (TSP) is a pitch effect that arises from temporally separated, highly correlated waveforms and is related to the reciprocal of time delay between the leading edges of such waveforms. On the assumption that spectral cues are responsible for TSP perception, it was suggested that random triggering of dc pulse pairs with fixed time delay would render the spectrum unspecifiable in an exact sense, thereby degrading the performance of subjects matching pure tones in pitch to TSP. On the assumption that a time-analyzing mechanism is responsible for TSP perception, it was predicted that the presentation of single, nonrepetitive dc pulse pairs would make TSP difficult to perceive since minimum information on which to base a pitch judgment would be available per unit time. The results were not as predicted, i.e., the distributions of pitch matches were essentially the same for conditions of random triggering and single pulse pairs and were highly similar to those generated with regularly triggered dc pulse pairs. These results suggest that the amount of "information" available per unit time is not particularly important to TSP perception and, further, that the assumption concerning a spectral mechanism does not hold.

Audition

“…McClellen & Small (91,92) have investigated what has been called time separation pitch described as an effect arising from temporally separated, highly correlated wave forms. A pitch effect is perceived when a train of AC pulses is delayed with respect to another identical train of pulses, both presented monaurally.…”

Directional guidance method for the blind using time separation pitch discrimination of triple pulse signals

“…Two subjects matched a sine wave to the TSP of standard signals yielding a mean frequency of 485 Hz. TSP perception requires successive pulses to be broadband and highly correlated (McClellan & Small, 1965, 1966, 1967Yost, Hill & Perez-Falcon, 1978). Therefore, the same pulse was repeated for all signals in both experiments.…”

“…Because TSP perception does not seem to vary significantly with signal sound pressure level (Small & McClellan, 1963;McClellan & Small, 1966;McClellan & Small, 1967;Yost, 1982), the subjects were allowed to adjust the sound volume to a comfortable working value at the beginning of each session. During the sessions, the computer program randomized the order of the signal presentations between positive and negative test signals, and between test signals and standard signals on a trial-to-trial basis by a Gellermann series (Gellermann, 1933).…”

“…A pitch can be heard even when the frequency spectrum of the pulses has no energy at the TSP frequency. In previous experiments, researchers have examined either pulse trains (Yost, Hill & Perez-Falcon, 1978;Warren & Bashford, 1981), pulse pairs (McClellan & Small, 1967), or interactions of two pulse trains (Thurlow & Small, 1955;Small & McClellan, 1963;McClellan & Small, 1965). The literature contains little information about TSP perception in distinct pulse triplets (Ceruti, Floyd & Martin, 1982;Ceruti, Martin & Floyd, 1983).…”