| 摘要 |
PURPOSE:To attain an excellent reception state, by inserting a parallel resonance circuit between a plurality of antennas and a changeover switch and resonating this circuit to a reception frequency. CONSTITUTION:A parallel resonance circuit 81 includes a coil 83, a capacitor 84, and a voltage dependant varactor diode 85, and an antenna 10 is connected to the coil 83 via the capacitor 84. A voltage is applied to the diode 85 via a line 87 and a resistor 88 from a front end circuit 42. Further, a parallel resonance circuit 82 includes a coil 93, a capacitor 94, a voltage dependant diode 95, a capacitor 96, and a resistor 98 and also a capacitor 99 to pass through high frequencies. When a line 55 is at high potential, a transistor TR103 is conductive, a signal is given to a circuit 42 from the antenna 10 via the circuit 81, and when a line 56 is at high potential, a TR104 is conductive, and a signal is transmitted to the circuit 42 via the circuit 82 and an FET102 from an antenna 18. |
