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:
Feb. 20, 1996
Filed:
Nov. 21, 1994
Ken-ichi Takai, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
A feedforward distortion compensation circuit includes a main amplification path, an auxiliary amplification path, first and second transmission paths, a signal attenuation path, a first signal injector, a first signal distributor, a second signal injector, a first signal synthesizer, a first phase difference detector, a first level detector, a second phase difference detector, a second signal synthesizer, a second level detector, and a control circuit. The control circuit controls a first variable attenuator and a first variable phase shifter such that a detection level of the first level detector becomes minimum, and first pilot signals synthesized by the first signal synthesizer on the basis of a phase difference detected by the first phase difference detector respectively have opposite phases, and controls a second variable attenuator and a second variable phase shifter such that a detection level of the second level detector becomes minimum, and second pilot signals synthesized by the second signal synthesizer on the basis of a phase difference detected by the second phase difference detector respectively have opposite phases.