Vocal production mechanisms in the budgerigar (Melopsittacus undulatus): the presence and implications of amplitude modulation.

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State: Public
Version: Final published version
Serval ID
serval:BIB_279897E16887
Type
Article: article from journal or magazin.
Collection
Publications
Title
Vocal production mechanisms in the budgerigar (Melopsittacus undulatus): the presence and implications of amplitude modulation.
Journal
Journal of the Acoustical Society of America
Author(s)
Banta Lavenex P.
ISSN
0001-4966
ISSN-L
0001-4966
Publication state
Published
Issued date
1999
Peer-reviewed
Oui
Volume
106
Number
1
Pages
491-505
Language
english
Notes
Publication types: Comparative Study ; Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, Non-P.H.S. Publication Status: ppublish
Abstract
In this paper acoustic evidence is presented for the presence of amplitude modulation in budgerigar (Melopsittacus undulatus) contact calls and learned English vocalizations. Previously, acoustic analyses of budgerigar vocalizations have consisted solely of visual inspection of spectrograms or power spectra (derived from Fourier transformation). Such analyses have led researchers to conclude that budgerigar vocalizations are primarily frequency-modulated, harmonic vocalizations. Although budgerigar calls have been shown to contain regions that are modulated in amplitude, the implications of this fact have been largely ignored. Amplitude modulation, the nonlinear interaction between two separate signals that results in the creation of new, heterodyne (sum and difference) frequencies, can produce a very complex Fourier spectrum that may resemble that produced by a harmonic vocalization. In this paper, the acoustic principles necessary for identifying amplitude modulation present in signals are outlined, and followed by data demonstrating that amplitude modulation is a prominent feature not only of natural budgerigar contact calls, but also of their learned English vocalizations. It is illustrated how analyzing a vocalization that contains amplitude modulation as if it were harmonic can result in misinterpretations of the acoustic and physical properties of the sound and sound source. The implications of amplitude modulation for studies of the ontogenetic, physical, and neural basis of budgerigar vocalizations are discussed, and a potential model for how the budgerigar syrinx may function to produce amplitude modulation is proposed.
Keywords
Animals, Behavior, Animal/physiology, Models, Biological, Parrots/physiology, Phonetics, Sound Spectrography, Speech/physiology, Speech Acoustics, Speech Production Measurement, Time Factors, Vocalization, Animal/physiology, Voice/physiology
Pubmed
Web of science
Create date
25/10/2012 13:43
Last modification date
20/08/2019 13:06
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