| 摘要 |
A television tuner includes (i) an FM trapping circuit including a parallel resonance circuit that resonates to an FM broadcasting band and a first switching diode which is connected in parallel to the parallel resonance circuit; and (ii) a switching transistor for controlling the on/off state of the first switching diode. The collector of the switching transistor is connected to a power source via a pull-up resistor, and the emitter thereof is grounded. A predetermined forward bias voltage is applied to the anode of the switching diode, the cathode thereof is connected to the collector of the switching transistor via another resistor, and a switching voltage for turning on/off the switching transistor is applied to the base of the switching transistor.
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