Document Detail


Propagation of beluga echolocation signals.
MedLine Citation:
PMID:  3655114     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The propagation characteristics of high-frequency echolocation signals (peak energies above 100 kHz) of the beluga (Delphinapterus leucas) were measured while the animal performed a target detection task. The whale was trained to station on a bite plate so that its transmission beam could be measured in the vertical and horizontal planes using hydrophone arrays. The transitional region between the acoustic near- and farfields was also located using an array of hydrophones that extended directly in front of the animal in the horizontal plane. Three distinct modes of signals were observed. Mode 1 signals had click intervals greater than the time required for the signals to travel to the target and back (two-way transit time). Mode 2 signals had click intervals shorter than the two-way transit time, and mode 3 signals had high repetition rates with an average click interval of 1.7 ms, approximately 2% of the two-way transit time. The average click intervals for the modes 1 and 2 signals were 193 and 44 ms, respectively. The vertical and horizontal beam patterns of the mode 1 signals had similar 3-dB beamwidths of approximately 6.5 degrees. The major axis of the vertical beam was directed approximately 5 degrees above the plane defined by the animal's teeth. The near- to farfield transition region was approximately 0.64-0.75 m from the tip of the animal's mouth.
Authors:
W W Au; R H Penner; C W Turl
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  The Journal of the Acoustical Society of America     Volume:  82     ISSN:  0001-4966     ISO Abbreviation:  J. Acoust. Soc. Am.     Publication Date:  1987 Sep 
Date Detail:
Created Date:  1987-11-18     Completed Date:  1987-11-18     Revised Date:  2006-12-27    
Medline Journal Info:
Nlm Unique ID:  7503051     Medline TA:  J Acoust Soc Am     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  807-13     Citation Subset:  IM    
Affiliation:
Naval Ocean Systems Center, Kailua, Hawaii 96734.
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MeSH Terms
Descriptor/Qualifier:
Animals
Cetacea / physiology*
Cues
Echolocation*
Male
Orientation*
Vocalization, Animal*
Whales / physiology*

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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