In electronics, ring modulation is a signal processing function, an implementation of frequency mixing, in which two signals are combined to yield an output signal.
A ring modulator may be used in music synthesizers and as an effects unit.
The Ring Modulator was so named because of the ring of (usually) highly matched diodes on a schematic drawing.
You don't even have to know how to read a schematic to find it. "What's that little ring of parts over there?"
The effect is the same as a doubly-balanced modulator and four-quadrant multiplier. Aren't you happy?
If you have two audio signals and put them into a ring modulator, the output has some very specific and strange characteristics.
Say one signal is rain in the trees "pink noise" and the other is your voice.
While you speak, it appears the trees are speaking to us through variation in the rain noise.
It's very disconcerting the first time you hear it.
If either you stop talking or the rain dries up, that's the end of the output. Neither of the two original signals is present in the output, but the interaction between them is.
Both Color and Colour Television use ring modulators (but not black and white TV) as does Stereo FM (but not Mono FM) and Single Sideband Ham Radio.