Harmonic

If a signal (representing acceleration, displacement, sound pressure etc.) is composed of a number of components of frequencies which are all integer multiples of one (fundamental) frequency, these components are said to form a harmonic train. The component at twice the fundamental frequency would be known as the second harmonic, the component at three times the fundamental frequency the third harmonic, and so on. Harmonic response is the periodic response of a vibrating system exhibiting the characteristics of resonance at a frequency that is a multiple of the excitation frequency.

Fundamental, 2^nd, 3^rd, 4^th, 5^th, 6^th and 7^th harmonic.

See also: Clipping, Frequency, Missing Fundamental, Overtone, Subharmonic, Subsynchronous.