Acoustic feedback correction
CA 2249283 C · Owner: Ensor, Jonathan Edward · Inventors: Lewis, Alwyn Vaughan; Ensor, Jonathan Edward
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
In a video conference facility, an echo cancelling device is provided which comprises an adaptive finite impulse response filter (38) operable to sample the input signal to a loudspeaker (30) and to model on the basis of that , signal, the signal fed back to a microphone (32). The echo cancelling device further comprises a combiner (36) for subtracting the model feedback signal from the microphone output signal to provide a corrected microphone output signal, and a microprocessor (40) programmed to read the corrected and uncorrected microphone output signal and to compute updates to the weights of the filter (38), the computation including a multiplication by a variable scaling …
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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 April 2, 1997 and granted June 3, 2003. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended April 2, 2017.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 2, 2019.
- 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.