Network echo canceller
CA 2123002 C · Owner: Sih, Gilbert C. · Inventors: Sih, Gilbert C.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An echo canceller and method for cancelling in a return channel signal an echoed receive channel signal where the echoed receive channel signal is combined by an echo channel (142) with an input return channel signal. A control unit (152) determines from the receive channel signal, the combined signal and first and second , echo residuals, one of a plurality of control states wherein a first control state is indicative of a receive channel signal above a first predetermined energy level, wherein when the control unit (152) is in the first control state it generates the first control signal and generates the second control signal when at least one of a first energy ratio of the first …
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 September 24, 1993 and granted December 9, 2003. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended September 24, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by September 24, 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.