Speech intercommunication systems particularly for hands-free loudspeaker telephones
CA 1048186 A · Owner: Matsushita Electric Industrial Co. Ltd. · Inventors: Mafune, Yasuo; Takahashi, Juhei
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An intercommunication system comprises a transmit channel and a receive channel. The transmit channel includes a microphone operative in a transmit mode and a first variolosser circuit and the receive channel includes a loudspeaker operative in a receive mode, a manually gain-adjustable circuit and an automatic gain control amplifier. The first and second variolosser circuits each provide a variable amount of loss and permit the high frequency region of the voice-frequency band to pass therethrough and have a mode wherein the amount of loss is relatively large. A first signal is derived from the transmit channel and a second control signal is derived from the receive channel in the transmit …
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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 February 6, 1979. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended February 6, 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.