摘要 |
A memory stores optimum capacitance values of a variable capacitor obtained by measuring in advance depending on temperatures. In practical use, a controller reads an optimum capacitance value from the memory according to a temperature obtained by a temperature sensor, and sets a capacitance value of the variable capacitor to the optimum capacitance value. Thus, a tuning frequency can be always adjusted to the frequency of a radio wave transmitted. Also, deviation of the tuning frequency due to variations in the production process can be remedied by varying the capacitance value according to data stored in the memory.
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