| 摘要 |
PURPOSE:To freely adjust the electrostatic value of a varactor diode and its variable magnification, to improve tuning characteristics, and to obtain an effect to tracking adjustment, by optionally varying the voltage characteristics of a power source for applying a voltage to the varactor diode. CONSTITUTION:A variable inductance 1 and a varactor diode 2 are connected in parallel, and the diode 2 is supplied with the output of a power source circuit 8, composed of variable voltage circuits 5 and 6 and a variable resistor 7 after the adjustment of a variable adjusting circuit 9. The circuits 5 and 6 couple with the variable inductance 1 to vary the tuning frequency of a tuning circuit. When the movable contact of a variable resistor R7 is moved toward the side of the circuit 5 or 6, the upper limit and lower limit of the capacity value of the diode 2 are adjusted easily, its variable magnification is set easily, and tracking adjustment is facilitated. |
