VCO is an oscillating circuit whose output frequency corresponds to the input control voltage. The frequency is a function of the input signal voltage of VCO. The working state of the oscillator or the parameters of the oscillating circuit are controlled by the input control voltage, which can constitute a VCO. The types of VCO are LC VCO, RC VCO and crystal VCO. The technical requirements of VCO mainly include: good frequency stability, high control sensitivity, wide frequency modulation range, frequency offset and control voltage into a linear relationship and suitable for integration.
