Discrimination of the phase of amplitude modulation applied to different carriers: Effects of modulation rate and modulation depth for young and older subjects.
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Publication Date
2019-09Journal Title
The Journal of the Acoustical Society of America
ISSN
0001-4966
Publisher
Acoustical Society of America
Volume
146
Issue
3
Pages
1696
Language
eng
Type
Article
This Version
AM
Physical Medium
Print
Metadata
Show full item recordCitation
Moore, B., & Sęk, A. P. (2019). Discrimination of the phase of amplitude modulation applied to different carriers: Effects of modulation rate and modulation depth for young and older subjects.. The Journal of the Acoustical Society of America, 146 (3), 1696. https://doi.org/10.1121/1.5126515
Abstract
The discrimination of amplitude modulation (AM) from frequency modulation (FM) of a 1000-Hz carrier, with equally detectable AM and FM, is better for a 2-Hz than for a 10-Hz modulation rate. This might reflect greater sensitivity to temporal fine structure for low than for high rates. Alternatively, AM-FM discrimination may depend on comparing fluctuations in excitation level on the two sides of the excitation pattern, which are in phase for AM and out of phase for FM. Discrimination of the relative phase of fluctuations might worsen with increasing rate, which could account for the effect of rate on AM-FM discrimination. To test this, discrimination of the phase of AM applied to two sinusoidal carriers was assessed, with a band of noise between the two carriers to prevent use of within-channel cues. Young and older subjects with normal hearing were tested. Performance was almost constant for AM rates from 2 to 10 Hz, but worsened at 20 Hz. Performance was near chance for AM depths near the detection threshold. The results suggest that the superior AM-FM discrimination at 2 Hz cannot be explained in terms of comparison of the phase of fluctuations on the two sides of the excitation pattern.
Keywords
Humans, Acoustic Stimulation, Auditory Threshold, Pitch Discrimination, Hearing, Aging, Adult, Aged, Middle Aged, Female, Male
Sponsorship
EPSRC (EP/M026957/1)
Identifiers
External DOI: https://doi.org/10.1121/1.5126515
This record's URL: https://www.repository.cam.ac.uk/handle/1810/297814
Rights
All rights reserved