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. 20, 1993
Filed:
Mar. 05, 1992
Yasushi Nishimura, Tokyo, JP;
Pioneer Electronic Corporation, Tokyo, JP;
Abstract
A VCA circuit is used at an input stage of communication device, an OA device or the like. The VCA circuit includes an output varying circuit which distributes a current supplied from a power supply side in accordance with a predetermined coefficient. The VCA circuit also includes an operational amplifier provided on an input side of the output varying circuit, and a feedback resistor connected between one of two input terminals and an output terminal of the operational amplifier. An input signal is applied to one of the two input terminals of the operational amplifier, a signal output from the output varying circuit is applied to the other input terminal. An output signal of the VCA circuit is drawn from the output terminal of the operational amplifier. An offset current generated in the output varying circuit can be reduced by varying the predetermined coefficient since the operational amplifier and the feedback resistor are provided on the input side of the output varying circuit and the output signal of the output varying circuit is applied to one of the two input terminals of the operational amplifier.