Noise controller
CA 2106338 C · Owner: Terai, Kenichi · Inventors: Hashimoto, Hiroyuki; Nakama, Yasutoshi; Tamura, Tadashi
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An active noise controller includes a prediction filter which comprises a delayer for delaying the noise or error detection signal by a predetermined period of time a first, adaptive filter for processing the output of the delayer to deliver its periodic component, and a subtractor for subtracting the output of the first adaptive filter from the noise detection signal to deliver a random component of the signal. More specifically, the prediction filter is capable of dividing the noise or error detection signal into two periodic and random, components. In addition two, second, and third, adaptive filters are provided for processing the periodic and random components respectively. …
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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 September 16, 1993 and granted November 30, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended September 16, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by September 16, 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.