Perceptual coding of audio signals
CA 2002015 C · Owner: Hall, Joseph Lindley Ii · Inventors: Hall, Joseph Lindley Ii; Johnston, James David
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A technique for the masking of quantizing noise in the coding of audio signals is adapted to include geometric interpolation between the thresholds for a tone masking noise and for noise masking a tone in order to reduce use of bit-rate, capability where it is not necessary for transparent or high quality. The technique is usable with the types of channel coding known as "noiseless" or Huffman coding and with variable radix packing. The stereophonic embodiment eliminates redundanciesin the sum and difference signals so that the stereo coding uses significantly less than twice the bit rate of the comparable monaural signal. The technique can be used both in transmission of signals and in …
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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 November 1, 1989 and granted December 27, 1994. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 1, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 1, 2011.
- 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.