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:
Aug. 09, 2011
Filed:
Aug. 15, 2008
Manabu Kawabe, Hachioji, JP;
Satoshi Tanaka, Kokubunji, JP;
Yoshikazu Nara, Yokohama, JP;
Renesas Electronics Corporation, Kawasaki-shi, JP;
Abstract
The present invention aims to efficiently calibrate the characteristics of a pair of reception or transmission low-pass filters by a receiving or transmitting circuit. A semiconductor integrated circuit includes an RF receiver that processes an RF reception signal, an RF transmitter that generates an RF transmission signal and a frequency synthesizer. A reception low-pass filter of the RF receiver suppresses undesired components contained in I and Q baseband reception signals. A transmission low-pass filter of the RF transmitter suppresses noise due to D/A conversion, which is contained in I and Q transmission analog baseband signals. A calibration test signal is supplied to the inputs of the pair of reception or transmission low-pass filters. A difference in phase between the pair of filters is detected by a phase detection unit. A calibration controller calibrates a relative mismatch between the cut-off frequencies of the pair of filters.