What is ring oscillator?

A ring oscillator is a type of electronic oscillator that generates a continuous wave of oscillating signals. It consists of an odd number of inverting amplifier stages connected in a ring configuration, with the output of each stage connected to the input of the next stage. The output of the last stage is fed back to the input of the first stage, creating a closed loop.

The oscillation frequency of a ring oscillator is inversely proportional to the delay through each stage, which is typically determined by the amplifier's gain-bandwidth product and input capacitance. The number of stages in the ring oscillator, as well as the delay through each stage, determine the overall frequency of oscillation.

Ring oscillators are commonly used in digital circuits for generating clock signals, as well as in frequency synthesis and phase-locked loops. They are also used in testing and measurement applications for generating frequency references and timing signals.

One of the advantages of ring oscillators is that they are simple to design and implement, using only a few components. However, they can be susceptible to noise and variations in component parameters, which can affect the stability and accuracy of the oscillation frequency. Additional measures such as biasing circuits and feedback control can be used to improve the performance of a ring oscillator.