Path: utzoo!utgpu!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!unmvax!pprg.unm.edu!hc!ames!pasteur!agate!e260-2d.berkeley.edu!c60a-2di
From: c60a-2di@e260-2d.berkeley.edu (The Cybermat Rider)
Newsgroups: comp.sys.next
Subject: Re: Fwd: LSC problem
Summary: Stealth
Message-ID: <17953@agate.BERKELEY.EDU>
Date: 7 Dec 88 08:26:55 GMT
References: <4000001@altair> <32595@bbn.COM>
Sender: usenet@agate.BERKELEY.EDU
Organization: University of California, Berkeley
Lines: 33

In article <32595@bbn.COM> jr@bbn.com (John Robinson) writes:
>In article <4000001@altair>, boyle@altair writes:

[misc. stuff about sound cancellation deleted]

>The only thing I am aware of that works something like this is the
>conjugate mirror stuff (see a recent SciAm article) for coherent
>light.

The device (if my memory serves me correctly) is called a "phase
conjugator".  Constructing a similar device for sound would be pretty
difficult, coz you still have to worry about the delay between the original
and conjugated waves.

>        Maybe if they would tell us about how the stealth planes work
>too.

The way I see it, Stealth merely ABSORBS or DEFLECTS radar waves to ensure
that they don't return to the receiver and betray its position.  Sound
cancellation equipment probably isn't built-in, since it's designed to fly
SLOW and (given its SIZE) HIGH, so unless you're thinking of a ground-based
equivalent of "Big Ears", such expensive (and probably cumbersome) equipment
probably isn't necessary.

>--
>/jr
>jr@bbn.com or bbn!jr


----------------------------------------------------------------------------
Adrian Ho a.k.a. The Cybermat Rider	  University of California, Berkeley
c60a-2di@web.berkeley.edu
Disclaimer:  Nobody takes me seriously, so is it really necessary?