| 摘要 |
PURPOSE:To minutely adjust a bias voltage to each varactor diode without incurring effect on other varactor diodes by applying a power supply voltage to a bias voltage adjusting resistance circuit and a voltage stabilizing circuit via a constant voltage circuit with temperature compensation and applying a frequency operating voltage to each bias voltage adjusting resistance circuit via the voltage stabilizing circuit. CONSTITUTION:A bias voltage is applied to a bias voltage applying point P of each varactor diode VCD from a +B power supply BS via a constant voltage circuit TCVC with temperature compensation, a variable voltage circuit VVC in interlocking with a variable inductance element L of a mu tuning circuit TC, and a bias voltage adjusting resistance circuit R corresponding to a variable voltage stabilizing circuit VVSC and each said varactor diode VCD. Since the current capacity is improved by the voltage stabilizing circuit VVSC and a required bias current is applied, each tuning circuit functions sufficiently. Further, the constant voltage circuit with temperature compensation TCVC is provided, even if the +B power supply BS is fluctuated because of the increase in temperature and humidity, the bias voltage is adjusted accurately and precisely. |
