VCOs (Voltage Controlled Oscillators)

A voltage-controlled oscillator (VCO) is a type of electronic oscillator that is used to generate a periodic electrical signal. The frequency of the generated signal can be controlled by varying the voltage applied to the oscillator. VCOs are commonly used in a variety of applications, including radio and telecommunications systems, where the frequency of the oscillator needs to be adjusted to match the frequency of the signal being transmitted or received. VCOs are typically composed of a circuit that includes an amplifier, an inductor or resonator, and a capacitor. The amplifier is used to amplify the oscillating signal, while the inductor or resonator is used to filter and shape the signal. The capacitor is used to control the frequency of the oscillator by providing positive feedback to the amplifier. When a voltage is applied to the VCO, it will oscillate at a frequency that is determined by the values of the inductor, resonator, and capacitor in the circuit. Crystals, oscillators, and resonators are all components that can be used in conjunction with VCOs to provide a stable reference frequency for the oscillator. Crystals and oscillators are used to generate a precise, stable frequency that can be used as the reference for the VCO, while resonators are used to filter and amplify the reference signal. These components are typically integrated into the VCO itself, or they may be separate components that are connected to the VCO.