Low distortion oscillator circuit using varactor diodea

Shown is a low distortion oscillator circuit using varactor diodes . The use of varactor diodes (or double varactor
diodes) in transistor oscillators can achieve electrical tuning and can also be made into voltage-controlled oscillators, usually for low-control oscillators.
    Inductors and capacitors connected in parallel can form an LC parallel resonant circuit. In the resonant circuit, the varactor diode is essentially equivalent to a variable
capacitor. The DC control voltage is added to the varactor diode to fine-tune the junction capacitance of the varactor diode. the size of. Therefore, the DC control voltage can also
be said to be a tuning voltage. Changing the control voltage value can change the oscillation frequency of the oscillator.