Voice activity detector for controlling echo canceller
CA 2111939 C · Owner: Nec Corporation · Inventors: Hasegawa, Atsushi
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
In a voice activity detector for an echo canceller a difference is, detected between a voltage at the receive path of a four-wire circuit of a hybrid transformer and a voltage at the transmit path of the four-wire circuit the difference, producing a first difference signal and an echo return loss estimate is derived from the first difference signal. The first difference signal is compared with the loss estimate to produce a first binary signal. A difference is detected between the voltage at the transmit path and an output voltage of the echo canceller to produce a second difference signal, and an echo return loss enhancement estimate is derived from the second difference signal. The second …
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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 December 20, 1993 and granted October 27, 1998. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended December 20, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 20, 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
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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.