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. 29, 2000
Filed:
Oct. 21, 1997
Tetsuya Takaki, Tokyo, JP;
NEC Corporation, , JP;
Abstract
In a receiver used in radio communication, when two or more interfering waves having different frequencies exist (other than a received signal frequency), a deterioration of a receiving sensitivity by a cross modulation signal produced by a non-linearity of a high-linearity of a high-frequency amplifier and a frequency converter is eliminated. The received signal from an antenna and an antenna sharer is provided via a first variable gain amplifier and via a band pass filter to a frequency converter. A local oscillating signal is mixed with these signals and a signal in an intermediate frequency band is outputted via a band pass filter to a second variable gain amplifier having a gain which is controlled such that an input signal power level of a demodulator is constant. A gain control signal of the second variable gain amplifier is used as a gain quantity. The control circuit obtains a gain control quantity based on the control signal, and also a power quantity of the received signal from a gain increase/decrease in each block of the receiver. The signal from the second variable gain amplifier is demodulated by the demodulator, converted to a base band signal, and after A/D conversion, fed to an error ratio calculation unit. A gain quantity control unit controls the gain quantity of the first variable gain amplifier.