Variable length code word decoder for use in digital communication systems
CA 2091815 C · Owner: Krause, Edward A. · Inventors: Shen, Paul; Moroney, Paul; Pollmann, Stephen C.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Apparatus (10) is provided for decoding variable length code words to recover transform coefficients, such as DCT transform coefficients provided by a high definition television encoder. A first category of the code words has a length of no more than n bits. A second category has a length of greater than n bits. A feedback ROM (22) is used to decode the code words. Code words from the first category are processed by directly addressing a lookup table (80) in the ROM (22). Code wards from the second category are processed using multiple passes through the ROM (22), wherein a portion of the data output during a prior pass is fed back (90) to address the memory during a subsequent pass.
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 March 17, 1993 and granted May 23, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended March 17, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 17, 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.