Signal distortion that occurs at harmonic intervals is known as what?

Harmonic distortion refers specifically to the alteration of a signal's original waveform that occurs when additional frequencies, which are integer multiples of the fundamental frequency, are introduced into the signal. This type of distortion is typically undesirable as it can affect the overall sound quality, making it less true to the intended output.

Total harmonic distortion (THD) is a measurement that quantifies the level of harmonic distortion present in a signal. It is expressed as a percentage and provides a comprehensive view of how much the harmonics contribute to the overall distortion of a signal. This metric is crucial for evaluating audio equipment, as lower total harmonic distortion values usually indicate clearer sound reproduction and less signal degradation.

In contrast, frequency distortion can refer to distortion that affects the overall frequency response but does not specifically highlight harmonic frequencies. Phase distortion pertains to the alteration of the phase relationships between various frequency components but does not necessarily indicate harmonic frequencies. Thus, total harmonic distortion is the most accurate choice as it encompasses the specific measurement of all harmonic distortions combined within a signal.