| 摘要 |
PROBLEM TO BE SOLVED: To provide a voltage controlled oscillator circuit hardly affecting the effect of an output capacitor in a loop filter connected to a control voltage terminal. SOLUTION: This voltage controlled oscillator circuit 10 consists of an amplifier circuit 2, a resonance circuit 3, a varactor diode D1, a choke element L1 whose one terminal connects to a cathode of the varactor diode D1, a capacitor whose capacitor C3 connected between the other terminal of the choke element L1 and ground, and a resistor R2 connected between the other terminal of the choke element L1 and a control voltage terminal 5. Thus, the sub-resonance of a resonance system of the voltage controlled oscillator circuit due to a capacitor built in the output side of a loop filter connecting to the control voltage terminal is eliminated to prevent abnormal oscillation of the voltage controlled oscillator circuit thereby making a relation between a control voltage and an oscillated frequency almost linear.
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