Acoustic calibration arrangement for a voice switched speakerphone
CA 2004170 C · Owner: American Telephone And Telegraph Company · Inventors: Miller, Robert Raymond Ii; Erving, Richard Henry
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Acoustic Calibration Arrangement for a Voice Switched Speakerphone Abstract of the Disclosure, An acoustic calibration circuit in a voice switched adaptive speakerphone accurately determines the type of acoustic environment in which the speakerphone is employed. The calibration circuit measures the acoustics of the room by emitting a tone burst through a loudspeaker associated with the speakerphone and measuring the returned time-domain acoustic response with a microphone also associated with the speakerphone. Obtained from this response and processed by a computer in the speakerphone are the maximum amplitude of the returned signal, and the duration of the echoes. The amplitude of the …
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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed November 29, 1989 and granted July 19, 1994. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 29, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 29, 2011.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.