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:
Aug. 03, 2004
Filed:
Sep. 07, 2001
Takao Hasegawa, Tondabayashi, JP;
Keiichi Sakuno, Nara, JP;
Sharp Kabushiki Kaisha, Osaka, JP;
Abstract
A power amplifier has a front and a rear stage. In the rear stage, to a base of a signal-amplifying bipolar transistor is connected one end of a variable impedance element whose impedance changes according to an input power level. An adjusting circuit is connected between the other end of the variable impedance element and a ground. A DC current adjusting element is connected between the other end of the variable impedance element and a supply voltage terminal. The front stage is made to perform class A operation or class AB operation near class A operation, while the rear stage is made to perform class B operation or class AB operation near class B operation. The distortion characteristic of the rear stage is adjusted by the variable impedance element, the adjusting circuit, and the DC current adjusting element so as to offset the distortion characteristic of the front stage.