Complex circuits require a frequency reference to advance the state of digital processors and other synchronous electronic circuits. A clock generator is a circuit that produces a timing signal-known as a clock signal, for use in synchronizing a circuit's operation. It can range from a simple symmetrical square wave to more complex arrangements. The basic parts that all clock generators share are a resonant circuit and an amplifier.
The resonant circuit is usually a quartz piezo-electric oscillator, although simpler tank circuits and even RC circuits may be used. The amplifier circuit usually inverts the signal from the oscillator and feeds a portion back into the oscillator to maintain oscillation.
