| 摘要 |
PURPOSE:To obtain + or -5X10<-4> stability without a complicated circuit by connecting a temperature compensating variable capacitance element, to which a temperature compensating element is connected, in parallel to a modulating variable capacitance element through a capacitor. CONSTITUTION:Temperature compensating diodes D2 and D3 are connected to the side of a power source voltage +V; and if the gradient of the temperature compensating characteristic is reverse, diodes D2 and D3 are connected in series to a resistance R4, and the reverse bias characteristic of a varactor diode VC2 due to the variation of temperature in case of series connection between diodes D2 and D3 and a variable resistance RV2 is opposite to that in case of series connection between diodes D2 and D3 and the resistance R4. Since the diode VC2 is connected to a tuning circuit through a capacitor C6, it is connected in parallel to a varactor diode VC1 through capacitors C2 and C6. Thus, the variation of the capacity of the diode VC2 is independent of the frequency characteristic to perform temperature compensation. |
