Periodicity analysis: Short term or long term?
Irwin W. Pollack · The Journal of the Acoustical Society of America · 1976
The exact repetition of a random auditory pattern results in a periodic signal. The strength of the resulting periodicity can be reduced by embedding random elements within the otherwise periodic pattern. Periodicity thresholds were obtained by finding the proportion of randomly embedded elements required by listeners to achieve a fixed discrimination level between repeated and nonrepeated patterns. If the location of the repeated elements within the pattern does not change from one repetition to the next, we have the condition appropriate either for a short-term, or for a long-term, periodicity analysis. If, however, the location of the repeated elements changes between successive repetitions, we have the condition appropriate for a short-term analysis, since a long-term periodicity analysis would reveal a nonperiodic signal. Periodicity thresholds are nearly equal under the two conditions; thereby suggesting a short-term periodicity analysis by the auditory system.