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:
Oct. 19, 1999
Filed:
Feb. 02, 1998
Abstract
A feedforward-type linear power amplifier directly compares amplitude and phase of a signal applied to one input end of a first signal canceler with amplitude and phase of a signal applied to another input end of the first signal canceler, and according to the comparison results, controls a first variable attenuator and a first variable phase shifter disposed in a pre-stage of the first signal canceler so that the first signal canceler extracts only the intermodulation distortion signals generated while a main power amplifier amplifies the RF input signal. Then, the linear power amplifier directly compares amplitude and phase of the intermodulation distortion signal on a main path with amplitude and phase of the intermodulation distortion signal on a sub path, and according thereto, controls a third variable attenuator and a third variable phase shifter to cancel the intermodulation distortion signals contained in the RF output signal of the main power amplifier.