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. 26, 1998
Filed:
Jun. 11, 1996
Norio Tozawa, Kawasaki, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
The present invention relates to a feed-forward amplifying device suitable for radio communications systems such as digital automobile telephones. The feed-forward amplifying device includes a distortion extracting loop circuit unit unit including a main amplifier which amplifies a main signal in a main signal system, the main amplifier having a first transistor and a first matching circuit arranged to at least one of the input side and the output side of the first transistor, the distortion extracting loop circuit unit generating a distortion extracted signal obtained by canceling a main signal component of an output from the main amplifier; and a distortion removing loop circuit unit including an auxiliary amplifier, with a passage delay time shorter than that of the main amplifier, which amplifies the distortion extracting signal from the distortion extracting loop circuit unit, the auxiliary amplifier including a second transistor with an output smaller than that of the first transistor and a second matching circuit arranged to at least one of the input side and the output side of the second transistor, the distortion removing loop circuit unit outputting only the main signal component from a signal in the main signal system at the rear stage of the main amplifier using the distortion extracted signal amplified by the auxiliary amplifier. The object of the invention is to improve the signal processing speed at a small power consumption and to realize a small, high-power feed-forward amplifying device.