Vco

A voltage-controlled oscillator or VCO is an electronic oscillator designed to be controlled in oscillation frequency by a voltage input. The frequency of oscillation is varied by the applied DC voltage, while modulating signals may also be fed into the VCO to cause frequency modulation (FM) or phase modulation(PM); a VCO with digital pulse output may similarly have its repetition rate (FSK, PSK) or pulse width modulated (PWM).

Voltage controlled oscillator is a electrical circuit which produces an oscillatory output voltage.We are applying an input voltage to the VCO which provides an output voltage that is proportional to the applied voltage signal.Oscillators consist of two transistors, an inductor, and a capacitor in an LC tank circuit, followed by a buffering amplifier. An oscillator circuit may be implemented with a tuned amplifier having positive feedback from the amplifier's output terminal to its input terminal.