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. 02, 2007
Filed:
Apr. 25, 2003
Naoki Kushima, Kobe, JP;
Kazuo Takayama, Kobe, JP;
Tetsuharu Imoto, Kobe, JP;
Kazushige Ogino, Kobe, JP;
Hirokazu Matsunaga, Kobe, JP;
Nobuyoshi Tateishi, Kobe, JP;
Naoki Kushima, Kobe, JP;
Kazuo Takayama, Kobe, JP;
Tetsuharu Imoto, Kobe, JP;
Kazushige Ogino, Kobe, JP;
Hirokazu Matsunaga, Kobe, JP;
Nobuyoshi Tateishi, Kobe, JP;
Fujitsu Ten Limited, Hyogo, JP;
Abstract
An object of the invention is to receive a weak signal with high sensitivity and reduce distortion and signal suppression when a strong interference signal exists. When a high-frequency signal received by an antenna is to be amplified by an antenna amplifier and when an interference wave of high field strength exists, a switch circuit is switched by an output switchover circuit from the output of an amplifier to a through-circuit. The through-circuit guides the high-frequency signal, directly to the output side without passing through the amplifier. When the switching operation of the switch circuit is performed based on low-frequency components which are highly correlated with distortion components due to intermodulation, the switching operation can be performed more adequately. Noises can be reduced by performing a smoothing process on the switching operation, and the use of an inverting amplifier can prevent occurrence of oscillation.