Data modulation arrangement for selectively distributing data
CA 2177163 C · Owner: Northern Telecom Limited · Inventors: Warwick, Alastair Anthony
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A cable television distribution arrangement is supplied via optical fibers with additional digital signals which are delivered to customers via coaxial drop cables (20) modulated at frequencies above those of the conventional analog television channels. A reduction in the required number of modulators is achieved while, delivering individually selected signals to individual customers by, supplying digital signals for a group of customers to a first modulator (72) and a pseudo data signal to a second modulator (84) and, selecting (78) between the outputs of the two modulators individually for each customer in the group. Switching between the outputs of the modulators is carried out during …
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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 7, 1994 and granted July 27, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended December 7, 2014.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 7, 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.