[Top] [All Lists]

Re: Energy distribution in pulsed vocalizations

Subject: Re: Energy distribution in pulsed vocalizations
From: Dave Mellinger <>
Date: Wed, 31 Jul 2002 13:46:29 -0700
Hello Harald,
 The side-bands are indeed revealed by spectrographic analysis.  Bradbury and 
 Vehrencamp's book Principles of Animal Communication (1998; Sinauer: 
Sunderland, MA) 
 has a good treatment of harmonics, amplitude modulation, frequency modulation, 
 beats.  It's worth reading if you're trying to puzzle these out.  Or even if 
 not, as it's a good book.
 The relative strength (intensity) of the various sidebands could indeed be 
caused by a 
 sound propagation effect.  For instance, a reflection off the surface or 
bottom could 
 increase or decrease the intensity of a certain sideband, depending on whether 
 was constructive or destructive interference (respectively) between the 
 sound and the reflected-path sound.  The frequencies affected could change 
with depth 
 of the whale or hydrophone, or simply with the distance between hydrophone and 
 Or the whale could be altering its sound production too.
 Dave Mellinger
 At 06:03 PM 7/30/02 -0400, you wrote:
 >From: Harald Yurk <[EMAIL PROTECTED]>
 >Subject: Energy distribution in pulsed vocalizations
 >Dear List Members 
 >I am studying the behavioral use of pulsed vocalizations by killer whales.
 >As many of you know those cetaceans produce discrete calls that can be
 >easily recognized by their spectrographical side band structure of their
 >pulsed vocalizations.
 >When calls are recorded with a single hydrophone, the greatest energy
 >measured from the spectrogram can be found on either one of those side
 >bands. As I understand it, those side bands are produced by an artifact of
 >the spectrographical analysis because a Fast-Fourier-Transformation always
 >assumes the existence of harmonics. The side bands, however reflect the
 >pulse repetition rate of pulsed signals (Watkins 1966). What I am curious
 >about and don't really understand, is why the highest energy is not always
 >found on the same side band. Are other physical conditions outside of the
 >sound producing whale responsible for those differences, or does body
 >movement affect the energy to shift between sidebands or .. ?
 >Maybe someone with better understanding of physical acoustics than myself
 >can help with this. Thank you very much.
 >Best regards,
 >Harald Yurk
 >Department of Zoology
 >Marine Mammal Research Unit
 >University of British Columbia
 >6270 University Boulevard
 >Vancouver, B.C., Canada V6T 1Z4
 >Phone:(604) 822-8181
 >Fax:(604) 822-8180

>From  Thu, 11 Jul 2002 09:15:26 -0700
From: nikolas francis <>
Date: Thu, 11 Jul 2002 09:15:26 -0700
Subject: Rat vocalizations

Hello, my name is Nikolas Francis.  I am a senior at The University of Iowa 
 and this fall I will be involved in a research project which requires as many 
 different rat vocalizations as possible to be played to a group of rats.  I 
 thought this would be a good place to ask if anyone knows of a good source to 
 find recordings of rat vocalizations.  If you know of any people or sound 
 banks that would help, please let me know. Thank you.
 Nikolas Francis
 The University of Iowa

<Prev in Thread] Current Thread [Next in Thread>

The University of NSW School of Computer and Engineering takes no responsibility for the contents of this archive. It is purely a compilation of material sent by many people to the Bioacoustics-L mailing list. It has not been checked for accuracy nor its content verified in any way. If you wish to get material removed from the archive or have other queries about the archive e-mail Andrew Taylor at this address: andrewt@cse.unsw.EDU.AU