HARMONIC DISTORTION

Modern technology's sensitive components present new challenges for plant engineers and others who design, specify, install, or maintain plants and equipment. For example, SCR and diode rectifiers in computers, copiers, solid-state lighting ballasts, and power conversion sections of adjustable frequency drives increase the need to thoroughly address harmonic distortion and its role in overall power quality.

A magnetic tape recorder's harmonic-distortion specification is very important. It usually determines where the record level of a recorder's electronics should be set. The record level is also used to determine the signal-to-noise ratio and frequency-response specifications. A typical harmonic-distortion specification might read "1% third harmonic of a 100-kHz signal at 60 ips." This means that the magnetic tape recorder has 1% third-harmonic distortion of a 100-kHz signal at 60 ips.

HARMONIC-DISTORTION DEFINITION

Harmonic distortion is the production of harmonic frequencies by an electronic system when a signal is applied at the input.

When an input signal goes through nonlinear electronic circuitry, the output signal will include some harmonic distortion (or unwanted frequencies).

If you analyzed this distortion, you'd see that a pattern exists. A pattern, whereby the frequency of each unwanted frequency is a multiple (X1, X2, X3, etc.) of the center frequency of the input signal.

There are two types of harmonic distortion: even-order and odd-order.