Path: utzoo!attcan!uunet!zephyr.ens.tek.com!tekfdi!videovax!bart
From: bart@videovax.tv.tek.com (Bart Massey)
Newsgroups: comp.dsp
Subject: Re: noise cancellation
Message-ID: <5845@videovax.tv.tek.com>
Date: 9 Jun 90 21:01:10 GMT
References: <595@mercury.iotek.UUCP> <1990Jun9.032245.2967@cunixf.cc.columbia.edu>
Reply-To: bart@videovax.tv.tek.com (Bart Massey)
Organization: Tektronix TV Measurement Systems, Beaverton OR
Lines: 15

A pilot friend of mine tells me that active noise-suppressing headsets are
quite common in small-plane cockpits now.  As you can imagine, this is a
*much* easier device to build, since there aren't any position or phasing
problems to cope with.  They are just a set of headphones, with microphones
just outside.  This way, cockpit noise can be actively cancelled, while
pilot radio audio is fed in with wires.  Note that the active cancellation
in this case doesn't depend on complicated analysis -- the inverted
microphone input at each ear is just added directly back into the headphone
speaker.

My apologies if any of the above is incorrect, as it's all 2nd or 3rd hand...

					Bart Massey
					..tektronix!videovax.tv.tek.com!bart
					..tektronix!reed.bitnet!bart