Low-delay code-excited linear predictive coder for speech or audio
CA 2005115 C · Owner: American Telephone And Telegraph Company · Inventors: Chen, Juin-Hwey
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A code-excited linear-predictive (CELP) coder for speech or audio transmission at compressed (e.g. 16 kb/s) data rates is adapted for low-delay (e.g. less than five ms. per vector) coding by performing spectral analysis of at least a portion of a previous frame of simulated decoded speech to determine a synthesis filter of a much higher order than conventionally used for decoding synthesis and then transmitting only the index for the vector which produces the lowest internal error signal. In other contexts, performing less critical portions of analysis on a previous frame of data has been termed "backward-adaptive". Two types of gain adaptation are used in respective implementations, both …
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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 December 11, 1989 and granted April 22, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended December 11, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 11, 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
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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.