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:
May. 04, 1999
Filed:
Mar. 11, 1997
Sadao Igarashi, Fukushima-ken, JP;
Kazuharu Aoki, Fukushima-ken, JP;
Satoshi Urabe, Fukushima-ken, JP;
Alps Electric Co., Ltd., Tokyo, JP;
Abstract
A multistage amplifier circuit comprises a current constant mode variable amplifying circuit for amplifying an input signal and current variable mode variable amplifying circuits and for further amplifying the signal amplified by the first variable amplifying circuit. An AGC voltage VAGC is commonly applied between the bases and emitters of an amplification degree control transistor of the current constant mode variable amplifying circuit and amplification degree control transistors of the current variable mode amplifying circuits. Collector currents of the transistors change exponentially with respect to the linearly-varied AGC voltage VAGC. Further, currents each proportional to the collector current of the transistor flow in the transistors. Thus, the gain PG �dB! of the current constant mode variable amplifying circuit changes linearly with the AGC voltage VAGC.