Digital virtual earth active cancellation system
CA 2076007 C · Owner: Noise Cancellation Technologies, Inc. · Inventors: Ziegler, Eldon W. Jr.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A digital virtual earth active cancellation system (14) which receives a phenomena input signal (r) representing residual phenomena to be cancelled and has an adaptive filter (44) which generates a cancellation signal (y). A system impulse response (c) is convolved with the cancellation signal (y) and is subtracted from the input signal (r) to produce an estimate of noise (x). The adaptive filter (44) produces the cancellation signal (y) by filtering the estimated noise (x) with a filter weight (a) that is adapted by the system impulse response (c). By convolving the estimate of noise (x) with the system impulse (c) to adapt the filter (44) the, values sent to an adapter (50) for the …
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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 February 7, 1991 and granted September 15, 1998. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended February 7, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 7, 2013.
- 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.