Transformer-less hybrid circuit
CA 2094639 C · Owner: American Telephone And Telegraph Company · Inventors: Laturell, Donald Raymond
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An improved transformer-less electronic isolating transformer is obtained with an output subcircuit that outputs a controlled current rather thanvoltage. Specifically the improved hybrid comprises an output drive subcircuit that receives an ac signal and creates a corresponding current that is passed to the line that supports two way communication. The subcircuit not only converts the applied voltage to current but includes means for effecting gain. Signals arriving to the hybrid from the line are applied directly to a near-end echo circuit that is also responsive to the signal applied to the output drive subcircuit. Both the input of the output drive subcircuit and the output of the …
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 April 22, 1993 and granted May 6, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended April 22, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 22, 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.