A method for eliminating acoustic echo in a communication device
CA 2102504 C · Owner: Motorola, Inc. · Inventors: Roney, Edward M. Iv; Potratz, Bryan A.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The process of the present invention operates on the voice codewords transmitted in a digital cellular radiotelephone environment. The process first determines if a voice is active (201) on the communications path from the base station to the radiotelephone. If a voice is present a threshold is, calculated (202). Any signals on the reverse path from the radiotelephone to the base station that are below this threshold (203) are replaced by noise that is at the same level as the ambient noise (204).
Read the whole patent
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 March 11, 1993 and granted April 22, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended March 11, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 11, 2015.
- 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.