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. 08, 2008
Filed:
Nov. 08, 2005
Masaki Yamamoto, Fukushima-ken, JP;
Masaaki Endo, Fukushima-ken, JP;
Masaki Yamamoto, Fukushima-ken, JP;
Masaaki Endo, Fukushima-ken, JP;
Alps Electronic Co., Ltd, Tokyo, JP;
Abstract
A variable gain amplifying circuit includes a gate-grounded amplifying FET and a collector-grounded amplifying transistor. A gate voltage of the FET and a base voltage of the transistor are adjusted by a supplied AGC voltage. When an input RF signal has small amplitude, the gate voltage is increased by a high AGC voltage so as to increase a main current of the FET, thereby increasing a signal gain of the FET. When the input RF signal has large or medium amplitude, the gate voltage is decreased by a low AGC voltage so as to decrease a main current of the FET, thereby decreasing the signal gain of the FET.