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:
Apr. 18, 1995
Filed:
Apr. 05, 1994
Yoshiaki Nagano, Itami, JP;
Fumihide Murao, Itami, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
There is disclosed a gain control amplifier wherein a signal input terminal (1) receiving an input signal (V.sub.in) is connected to a variable resistor portion (71) including an R-2R ladder resistor group and switches (K.sub.1 to K.sub.4), and an operational amplifier (10) and resistors (r.sub.1, r.sub.2, r.sub.3) construct an adding circuit (91), which outputs an output signal (V.sub.out) to a signal output terminal (5). Each of the switches (K.sub.1 to K.sub.4) includes terminals (A, B) and a common terminal (C) connected to one of the terminals (A, B). All of the terminals (A) arc connected to the signal input terminal (1) in common, and all of the terminals (B) are grounded in common. The ladder resistor group (R,2R) need not be of great resistance value. Thus, a gain control amplifier is achieved which is permitted to control a gain widely, finely and linearly without resistors of great resistance.