Harmonic spectrum: Difference between revisions

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The harmonic spectrum is the representation of the amplitude of each harmonic order with respect to its frequency.


== Principle  ==
{{FigureRef|M9}} shows an example of harmonic spectrum for a rectangular signal.


Each type of device causing harmonics draws a particular form of harmonic current (amplitude and phase displacement).<br>These values, notably the amplitude for each harmonic order, are essential for analysis.  
Each type of device causing harmonics draws a particular form of current, with a particular harmonic content. This characteristic can be displayed by using the harmonic spectrum.


== Individual harmonic distortion (or harmonic distortion of order&nbsp;h)  ==
{{Gallery|M9|Harmonic spectrum for a rectangular signal U(t)||
 
|DB422618a.svg||
The individual harmonic distortion is defined as the percentage of harmonics for order h with respect to the fundamental.<br><math>U_h(%)=100 \frac{U_h}{U_1}</math>&nbsp;
|DB422618b.svg||}}
 
or
 
<math>i_h(%)=100 \frac {I_h}{I_1}</math>&nbsp;
 
== Harmonic spectrum  ==
 
By representing the amplitude of each harmonic order with respect to its frequency, it is possible to obtain a graph called the harmonic spectrum.'''Figure M12 '''shows an example of the harmonic spectrum for a rectangular signal.
 
== Rms value  ==
 
The rms value of the voltage and current can be calculated as a function of the rms value of the various harmonic orders.<br><math>Irms=\sqrt {\sum_{h=1}^\infty I_h^2}</math>
 
and
 
<math>Urms=\sqrt {\sum_{h=1}^\infty U_h^2}</math>&nbsp;
 
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<br>[[Image:FigM12a.jpg|left]] <br><br><br><br><br><br><br><br><br><br><br><br><br>[[Image:FigM12b.jpg|left]] <br><br><br><br><br><br><br><br><br><br><br><br><br>
'''''Fig. M12:'''''<i>&nbsp;Harmonic spectrum of a rectangular signal, for a voltage U (t)</i>
 
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Latest revision as of 09:48, 22 June 2022

The harmonic spectrum is the representation of the amplitude of each harmonic order with respect to its frequency.

Figure M9 shows an example of harmonic spectrum for a rectangular signal.

Each type of device causing harmonics draws a particular form of current, with a particular harmonic content. This characteristic can be displayed by using the harmonic spectrum.

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