| 摘要 |
PURPOSE:To adjust properly mismatching between tuning circuits by selecting a variable voltage circuit, which sets a correcting capacity, in accordance with a channel selecting operation in the tuning circuit of the succeeding stage. CONSTITUTION:In an antenna tuning circuit, the channel selecting voltage from a voltage circuit 5 is impressed to a varactor diodes 3 and 3' for correction through a variable voltage circuit 4 to correct the tuning characteristic. Meanwhile, in a high frequency amplifying circuit, varactor diodes 7 and 7' are varied by the selecting voltage from the voltage circuit 5. That is, a channel is selected in accordance with a variable inductance 1, and a switch circuit 10 is switched by the channel selecting voltage to select variable voltage circuits 91-93 successively. Capacities of varactor diodes 8 and 8' for correction are set by the voltage of the selected variable voltage circuit to correct the tuning characteristic. Thus, mismatching between tuning circuits is adjusted properly. |
