| 摘要 |
PROBLEM TO BE SOLVED: To provide a tuner capable of preventing deterioration of receiving performance by preventing malfunctions of an AGC circuit by a jamming signal. SOLUTION: The tuner has a receiving part 1 which receives a radio signal, an RF_AGC circuit 3 which performs level adjustment of the received radio signal, a mixer circuit 5 which performs frequency conversion to the radio signal whose level is adjusted into an IF signal by multiplying the radio signal whose level is adjusted by a local oscillation signal, an OFDM demodulation IC 14 which demodulates the IF signal, a filter 21 for detection which attenuates components outside a predetermined band among frequency components of the IF signal and a detection circuit 9 which detects a level of the IF signal passing through the filter 21 for detection and the RF_AGC circuit 3 performs the level adjustment based on detection results of the detection circuit 9. COPYRIGHT: (C)2007,JPO&INPIT
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