| 摘要 |
PURPOSE: A negative voltage controlled crystal oscillator circuit is provided to enable a center frequency to be reduced in proportion to increasing of a control voltage. CONSTITUTION: A center frequency varied oscillator(21) has a variable center frequency using a varactor diode(DV2), which has an anode connected to receive a control voltage and a cathode connected to a power supply voltage. The center frequency varied oscillator(21) further comprises an input resistor(R3) receiving a control voltage(Vc), a crystal oscillator(X1) operating as an induction element, and capacitors(C1, C2) feeding back an output signal of an amplifier(22). The amplifier(22) amplifies an output signal of the oscillator(21) and simultaneously feeds back the amplified output signal. The amplifier(22) comprises a transistor(Q1) amplifying an output oscillation signal of the oscillator(21), and bias resistors(R1, R2) biasing the transistor(Q1).
|
