Dc control circuit
CA 1255026 A · Owner: Schingh, Pierre J. · Inventors: Schingh, Pierre J.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A DC control circuit for limiting metallic and longitudinal currents flowing in a balanced telephone line, and maintaining a predetermined DC bias voltage on tip and ring leads of the balanced line. A negative feedback path is established for monitoring voltage on the tip lead, comparing the monitored voltage with a predetermined offset bias voltage and generating a DC bias signal for application to tip and ring driver circuits for application to the balanced line in response thereto. Longitudinal and metallic currents are detected in a further pair of differential amplifiers for generating further DC signals such that a voltage corresponding to the detected longitudinal current is …
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
- Granted May 30, 1989. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended May 30, 2006.
- 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.