Perceptual coding of audio signals
CA 2027136 C · Owner: Johnston, James David · Inventors: Brandenburg, Karlheinz; Johnston, James David
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A method is disclosed for determining estimates of the perceived noise masking level of audio signals as a function of frequency. By developing a randomness metric related to the euclidian distance between (i) actual frequency, components amplitude and phase) for each block of sampled values of the signal and, (ii) predicted values for these components based on values in prior blocks it , is, possible to form a tonality index which provides more detailed information useful in, forming the noise masking function. Application of these techniques is illustrated in, a coding and decoding context for audio recording or transmission.
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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 October 9, 1990 and granted January 16, 2001. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended October 9, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by October 9, 2012.
- 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.