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Expired Canadian patentCanada

Voltage controlled current sources for active hybrid circuit

CA 1108328 A · Owner: Western Electric Company, Incorporated · Inventors: Sanderson, Richard B.

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Abstract From the Canadian patent

Sanderson 3, VOLTAGE CONTROLLED CURRENT SOURCES FOR ACTIVE HYBRID CIRCUIT Abstract of the Disclosure, An active hybrid circuit equipped with a resistor bridge, balance network and transmit and receive amplifiers for 2-wire to 4-wire long haul trunk communication between a telephone central office and a distantly located operator console is disclosed. High impedance current sources having voltage follower operational amplifiers are integrated into the hybrid for reducing hybrid bridge loading on the bidirectional 2-wire path while providing adjustable levels of transmission in all directions. One of the high impedance sources is responsive to signals received from the receive amplifier via a …

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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

  • Granted September 1, 1981. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended September 1, 1998.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledApril 14, 1978
GrantedSeptember 1, 1981
Term endedSeptember 1, 1998
Patent numberCA 1108328 A
Classification (IPC)H04M19/00 +1 more

Timeline

Timeline From CIPO dates

1979198119831985198719891991199319951997Application filedApril 14, 1978Patent grantedSep 1, 1981Term endedSep 1, 1998

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Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.