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. 30, 1991
Filed:
Oct. 25, 1989
Applicant:
Inventors:
Assignee:
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H03F / ; H03H / ;
U.S. Cl.
CPC ...
330252 ; 333214 ;
Abstract
A variable impedance circuit includes a first differential amplifier circuit having an input terminal pair, an output terminal pair and a capacitive element connected between the emitters of a transistor pair. The variable impedance circuit further inclludes a second differential amplifier circuit having an input terminal pair and an output terminal pair. The output terminal pair of the first differential amplifier circuit is connected to the input terminal pair of the second differential amplifier circuit. Furthermore, the output terminal pair of the second differential amplifier circuit is connected to the input terminal pair of the first differential amplifier circuit.