| 摘要 |
PROBLEM TO BE SOLVED: To provide a terrestrial digital broadcast receiving tuner capable of reducing the effect of disturbance by other channels. SOLUTION: A microcomputer 14 controls band pass filters 3, 5 and a PLL circuit 9 to sweep a reception frequency and the oscillated frequency of a voltage-controlled oscillator 7, uses an output from a demodulation circuit 13 during the sweep to detect a channel wherein the input electric field strength of a received signal with the reception frequency is a first threshold value or over, and compares the case that there is at least one input electric field strength difference between the detected channel and adjacent channels equal to or more than a second threshold value, with the case that all the input electric field strength differences between the detected channel and the adjacent channels are less than the second threshold value so as to decrease the setting of AGC voltages (V2, V3). COPYRIGHT: (C)2006,JPO&NCIPI
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