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Total Harmonic Distortion

Measure total harmonic distortion (THD) of signal

Library

Extras/Measurements

A discrete version of this block is available in the Extras/Discrete Measurements library.

Description

The Total Harmonic Distortion block measures the total harmonic distortion (THD) of a periodic distorted signal. The signal can be a measured voltage or current.

The THD is defined as the root mean square (RMS) value of the total harmonics of the signal, divided by the RMS value of its fundamental signal. For example, for currents, the THD is defined as

total harmonic distortion (THD) = IH/IF,

where

where

In = RMS value of the harmonic n
IF = RMS value of the fundamental current.

The THD has a null value for a pure sinusoidal voltage or current.

Dialog Box and Parameters

Fundamental frequency

The frequency, in hertz, of the fundamental signal.

Inputs and Outputs

signal

Connect this input to the voltage or current you want to measure the total harmonic distortion.

THD

The output returns the THD of the input signal.

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