Ripple noise

A composite value of a small AC voltage, which appears superimposed on a DC voltage as ripple, and high-frequency noise in rectifier and smoothing circuits of power supply equipment. It consists of the AC component that could not be removed by the low-pass filter in the rectifier and smoothing circuit, combined with high-frequency noise components other than the input sine wave. Like ripple, it is represented by one cycle from the peak of the waveform to the next peak.