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Stereo Mic Thinkpad Active Noise Canceling Headphones Disclosure Number: IPCOM000018731D
Original Publication Date: 2003-Aug-04
Included in the Prior Art Database: 2003-Aug-04
Document File: 1 page(s) / 48K

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This article describes a process to implement an inexpensive active noise cancelling headphone product, ideal for mobile customers of Thinkpad and NetVista branded PC's which implement the AD1981B AC'97 audio codec.

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Stereo Mic Thinkpad Active Noise Canceling Headphones

It is common for first class and business class airline passengers to receive a set of active noise cancelling headphones, as a "luxury" perk. Such current art headphones significantly reduce repetitive low frequency background noise, such as the air-conditioner noise and jet engine noise, thus making the customer's perceived ambient background noise much quieter than it is. Such headsets normally retail between $150 - $400.

The purpose of this article is to describe a process/technique of making an inexpensive active noise cancelling headset, one for approximately $10 (mfg'rs cost). This would allow such a desirable product to be inexpensive enough to be an impulse buy for most consumers, in particular customers of new Thinkpad and NetVista PCs.

Starting May 2003, most new Thinkpads and NetVista PCs will employ Analog Devices Inc. (ADI)'s new AD1981B AC'97 audio codec chip. This audio codec has been designed to accommodate a stereo mic input, allowing stereo record capability. ADI's main intent of this chip is aimed at allowing an inexpensive solution for a stereo array mic, allowing for accurate voice recognition functionality while a user is seated 12" - 18" away from the array microphone. Normally, voice recognition type microphones are required to be worn on the users head (headset mic), with the microphone located about 1 finger away from ones mouth.

However, the capability also allows one to use the ste...