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From: smith@sndpit.enet.dec.com (Willie Smith)
Newsgroups: comp.robotics
Subject: Re: Getting narrow-beam range data
Message-ID: <1291@sousa.ltn.dec.com>
Date: 8 Jun 91 12:04:14 GMT
Sender: newsa@sousa.ltn.dec.com
Organization: Digital Equipment Corporation
Lines: 18


In article <160412.13057@timbuk.cray.com>, 
	kilian@cray.com (Alan Kilian) writes...
>  I can understand that the beam divergence could be proportional to the
>transducer width but I don't see how a larger transducer can produce a narrower
>beam. Is this really true?
>  Also how does an array of transducers produce a narrow beam?

Correction, the beam width is _inversely proportional_ to transducer size.  
As the transducer size increases, the beam gets smaller.  An array of 
transducers acts just like a single larger one when you drive them right.  
Don't ask me for details, I don't have any, try Polaroid, they suggested it 
to me...

Willie Smith
smith@sndpit.enet.dec.com
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