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:
Jul. 09, 1996
Filed:
Feb. 17, 1995
Applicant:
Inventors:
Osamu Kurokawa, Hino, JP;
Buntaro Sawa, Sagamihara, JP;
Assignee:
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Primary Examiner:
Int. Cl.
CPC ...
H04B / ; H04M / ;
U.S. Cl.
CPC ...
455 79 ; 455 89 ; 379388 ; 379390 ;
Abstract
A hands-free circuitry in which, in order to prevent howling caused by acoustic coupling between a speaker and a microphone, a loss is inserted in a transmit audio path in a receive mode while a loss is inserted in a receive voice path in a transmit mode and values of the losses are controlled according to the volume set value of the speaker. Since the quantities of the losses are minimized when a howling margin is sufficient, simplex communication can be prevented that a user cannot listen to party's receive voice signal due to excessive attenuation.