Tone injection circuit
CA 1047148 A · Owner: Gte Automatic Electric Laboratories Incorporated · Inventors: Lee, David Q.; Mclaughlin, Donald W.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A precise tone injection circuit for injecting tone signals to a constant current junctor circuit in a two-wire balanced circuit. The tone injection circuit includes a pair of transistors operating as constant current sources feeding the respective ones of the two wires. A phase splitter amplifier couples a tone signal to the base electrodes of the transistors to change the current through their collector electrodes via the emitter circuits thereof at a rate and frequency of the tone signals at the base. Since a two-wire balanced circuit is used and the injected signal currents to each wire are 180° outof-phase, in-phase signals, that is, noise and voltage fluctuations, are reduced or …
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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 January 23, 1979. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended January 23, 1996.
- 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.