| 摘要 |
<P>PROBLEM TO BE SOLVED: To automatically correct deviation from a desired reception frequency of an oscillation frequency of a local oscillation circuit while reducing a load on an MCU. Ž<P>SOLUTION: During a tuning operation, an OSC 106 is oscillated at an oscillation frequency corresponding to the adjustment of a capacitor bank 107 and a varicap VR1. In such a case, when a frequency of an IF signal is obtained, an AFC operation is started, and a gate control circuit 121 counts a clock CK supplied from a crystal oscillator 131 via an oscillation control circuit 122 to generate a gate time corresponding to tuning information or the like. A gate circuit 109 is controlled in accordance with the gate time, and the oscillation frequency of the OSC 106 artificially measured by a counter circuit 110 is compared with a standard value held in a standard value holding circuit 114 by a comparison circuit 115. When it is determined that the oscillation frequency of the OSC 106 is within a specified frequency range, a VR2 control circuit 117 finely adjusts a varicap VR2 so as to maintain the oscillation frequency. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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