Telecommunications – Receiver or analog modulated signal frequency converter – Noise or interference elimination
Reexamination Certificate
2011-08-09
2011-08-09
West, Lewis G. (Department: 2618)
Telecommunications
Receiver or analog modulated signal frequency converter
Noise or interference elimination
C455S067130, C455S252100, C455S063100, C375S346000, C375S322000
Reexamination Certificate
active
07995982
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.
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Kawabe Manabu
Nara Yoshikazu
Tanaka Satoshi
Gonzales April G
Miles & Stockbridge P.C.
Renesas Electronics Corporation
West Lewis G.
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