Method and apparatus for communicating digital data using trellis coded qam
CA 2074553 C · Owner: Vizio · Inventors: Lery, Scott A.; Paik, Woo H.; Heegard, Chris
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Coded modulation schemes based on codes for QPSK modulation are directly incorporated into QAM based modulation systems, forming trellis coded QAM to provide a practical coding structure that is both efficient in bandwidth and data reliability. Concatenated coding with QPSK based trellis coding and symbol error correcting coding is used. In an encoder, an N-bit QAM constellation pattern is divided into four subsets, each including N/4 symbol points of the constellation pattern. A two-bit QPSK codeword is assigned to each of the four subsets. A symbol to be transmitted is first encoded using an outer error correcting encoding algorithm such as a, Reed-Solomon code. Part of the symbol is then …
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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 July 23, 1992 and granted March 2, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended July 23, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by July 23, 2014.
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Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.