Sine wave

A sine wave is a smooth, endlessly repeating wave. Its shape is given by the sine function and is described by three quantities:

• amplitude: how tall the wave is
• frequency: how quickly it repeats (the inverse of its period)
• phase: where in its cycle the wave starts

Sine waves model sound, light, alternating current, and other periodic signals. When two are added their phase difference determines whether they reinforce or cancel.