Multidimensional trellis-coded communication system
CA 2115946 C · Owner: American Telephone And Telegraph Company · Inventors: Wei, Lee-Fang
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A trellis-coded modulation system is provided in which the output of the trellis encoder (110) is used to select a subset of a multidimensional QAM constellation The selection, process is performed such that a) the minimum square Euclidean distance between valid sequences of successive selected subsets is maximized b) the resulting code is rotationally, invariant and c) the selected subset corresponding to a transition of the trellis encoder from a present state i to a different next state j is different from the selected subset that corresponds to a transition of the trellis encoder from a present state j to a next state i.
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 February 18, 1994 and granted October 27, 1998. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended February 18, 2014.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 18, 2016.
- 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.