VCO (Voltage Controlled Oscillators) can also be known as silicon oscillators or VCOs. They are electronic devices designed to control oscillation frequency by varying the DC voltage input. Oscillation frequencies can be adjusted from a few Hz to hundreds of GHz. The VCO's can also work as modulators of both frequency and phase by delivering a modulating signal to the control input. Voltage Controlled Oscillators are also commonly used as an integral part of the phase-locked loop.
Voltage Controlled Oscillators can be categorized into 2 types according to the type of waveform generated:
Linear / Harmonic Oscillator - this type of oscillator generates a sinusoidal type of waveform.
Relaxation Oscillator - This type of VCO is able to generate a triangular waveform or a sawtooth waveform.
There are several typical applications of VCOs and they are:
Some key parameters that need to be considered before selecting the VCO are: