Loudspeaking telephone with a variable gain circuit
CA 1294081 C · Owner: Nec Corporation · Inventors: Shimada, Keiko
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A loudspeaking telephone with a variable gain circuit comprises a receiving path including first amplifying means for amplifying a received signal by a first gain to provide a received speech signal. A transmitting path includes second amplifying means for amplifying a transmitted speech signal by a second gain to provide a transmitted signal and first means for comparing a signal level on the receiving path with a signal level on the transmitting path to provide a control signal to control the first and the second gains. Second means responsive to the control signal for switching between the first and second gains are provided to make one of the gains larger than the other of the gains …
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 January 7, 1992. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended January 7, 2009.
- 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.