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From: larry@kitty.UUCP (Larry Lippman)
Newsgroups: rec.audio,sci.electronics
Subject: Re: Digital systems of the future
Message-ID: <2048@kitty.UUCP>
Date: Mon, 28-Sep-87 22:06:10 EDT
Article-I.D.: kitty.2048
Posted: Mon Sep 28 22:06:10 1987
Date-Received: Wed, 30-Sep-87 00:55:06 EDT
References: <1041@rover.ri.cmu.edu>
Organization: Recognition Research Corp., Clarence, NY
Lines: 29
Summary: Digital Acoustic Reproducers
Xref: mnetor rec.audio:3467 sci.electronics:1445

In article <1041@rover.ri.cmu.edu>, nivek@rover.ri.cmu.edu (Kevin Dowling) writes:
> Recent posts on sending digital signals to speakers are not that far fetched.
> I envision speakers of the near future where only digital signals are sent
> to each speaker. 
> ...
> - Does someone have a pointer to a digital speaker system that was developed
> at MIT (?). I'm not sure but it may have used phased-array techniques to 
> generate the output.

	I don't know anything about this phased-array technique, but I recall
that a patent was issued and assigned to Bell Laboratories in the early 70's
concerning a true digital acoustic transducer.
	This transducer had concentric sections of increasing surface area.
Each section was individually driven, either through piezoelectric or
electrodynamic means.  Each section increased in area by a digital weighting
on the order of 1-2-4-8 etc.
	I had some reference material on this transducer, with was either a
copy of the patent or a Bell System Technical Journal article, but I cannot
locate it at the moment.  I believe the orignal intent of the device was for
use as a telephone handset receiver, but the design would lend itself to
loudspeakers.
	Obviously, this might be the ultimate in digital sound reproduction,
if it is practicable.
	Anyone know any more about this device?

<>  Larry Lippman @ Recognition Research Corp., Clarence, New York
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