The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 27, 1977
Filed:
Jan. 27, 1976
Applicant:
Inventors:
Yasuo Mafune, Yokohama, JA;
Juhei Takahashi, Yokohama, JA;
Assignee:
Matsushita Electric Industrial Co., Ltd., Osaka, JA;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H04M / ;
U.S. Cl.
CPC ...
179 / ;
Abstract
In an intercommunication system comprising transmit and receive channels including respective variolossers and being connectable through a hybrid transformer to an external line, the variolossers being so constructed as to allow a high frequency region of the voice frequency band to pass therethrough even when they express a large amount of loss, an AGC amplifier and a manually gain-controllable amplifier being provided in the receive channel, and the control input of the variolossers being picked up from different parts of the receive channel respectively in the transmit mode and the receive mode.