compendium

distortion factor and relative fundamental content

Whereas the effective value and the effective power are specified for mixed variables (contant component and alternating component), the specification of the constant component only refers to (pure) alternating variables.
The distortion factor is the deviation of a non-sinusoidal periodic time-function from the sinuoidal characteristic. The distortion factor can be defined as the ratio of harmoics to the effective value of the total voltage (after decomposing a non-siusoidal voltage into a number of harmonics using the Fourier analysis).:

  
(42)
another notation gives the distortion factor in percent k% :  
 
The distortion factor of the nth harmonic is called:  
(43)
A convenient way of calculating the distortion factor is to use the relative fundamental content g. The relative fundamental content g is the distortion coefficient of the 1st harmonic (fundamental wave:  
(44)
from the equations (42) and (44) it follows:  
(45)
Distortion factors of the same amount can appear different when visualized even if they have equal fundamental wave frequencies. This is so because they can be based on different harmonics (experiments in the distortion factor). The total distortion factor of assemly groups a, b, c, ... connected in a line is specified like this:  
 

It is used in:

  • the quantitative description of so called linear and non-linear distortions,
  • measureing the quality of components in sound-studios- and for hifi gear
  • the description of systems with filter properties

    • beispiel 7 beispiel 8