# A CDE Definition

harmonic

A multiple of a fundamental frequency occurring at the same time. For example, if the fundamental frequency is 1 kHz, the first harmonic is 1 kHz, the second harmonic is 2 kHz, and so on. Musical instruments oscillate at several frequencies, which are called "overtones." The first overtone is actually the second harmonic, and so on. See harmonic distortion.

harmonic distortion

In communications, unwanted frequencies that are generated as multiples of the original frequency due to irregularities in the transmission line. In audio amplifiers, harmonic distortion comes from non-uniform operation (non-linearity) in the amplifier circuits. See harmonic.

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