Noise controller
CA 2096926 C · Owner: Sako, Kazuya · Inventors: Nagami, Masaaki; Babasaki, Masahiro; Sako, Kazuya
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
In a noise controller which forms a noise cancelling sound having a phase opposite to and a sound pressure equal to those of a noise infiltrating into a closed space, any deviation in its transfer characteristics from the initial equalization is easily checked and judged owing to the provision of an adaptive filter 10 which automatically varies the filter coefficient and forms a cancelling signal for forming a cancelling sound a, coefficient updating means 11 which updates the filter coefficient based on an error signal after the noise has been cancelled, a second simulated transfer characteristics compensation means 13 which forms the initial equalization by simulating transfer …
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 May 25, 1993 and granted September 30, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended May 25, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 25, 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.