| 摘要 |
PURPOSE:To obtain an antenna tuner applied to various fields by using a voltage frequency/voltage-converted from a transmission wave inputted to the antenna tuner so as to decide a selected band of the tuner thereby setting automatically the band of the tuner. CONSTITUTION:An automatic antenna tuner section 3 is inserted between a transmitter 1 and an antenna 2 and provided with a matching circuit comprising a coil 31 and capacitors 32, 33. In the coarse adjustment of the band setting, a band is selected among preset bands so that an output voltage of an f/V converter 36 to the transmission radio wave 11 is located between the upper limit reference voltage and the lower limit reference voltage of the selected band. When a band is decide, a switch 34 is set to a prescribed location in addition to the setting of a switching control circuit 38: Since the output of the f/V conversion is zero at no input and the band is discriminated as the minimum band A, a carrier detection circuit 39 locks the switching control circuit 38 to prevent unnecessary switching of the band.
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