Asymmetric coupling method
CA 2205241 C · Owner: At&T Corp. · Inventors: Gough, Cameron; Morgan, Isaac E.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Downstream and upstream signals in a transmission system are attenuated by different amounts to allow upstream signals to be originated at individual subscribers (22-22 30-30), at the same level yet be received at a common upstream amplifier (19b) at substantially the same level. Different attenuation of downstream and upstream signals is achieved by the combination of a pair of directional couplers (110a and 110b) and a diplex filter (132). The couplers and diplex filter collectively separate a downstream signal destined for the subscriber from an upstream signal generated by the subscriber. The upstream signal which is separated may be attenuated by a matching loss element (138) to …
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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 May 13, 1997 and granted November 14, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended May 13, 2017.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 13, 2019.
- 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.