Understanding “THD” Total Harmonic Distortion       

Date: 10/1/2025
Time: 3:00 PM - 4:00 PM EST
Credit:1 hour

The total harmonic distortion, or THD, of a signal is a measurement of the harmonic distortion present and is defined as the ratio of the sum of the powers of all harmonic components to the power of the fundamental frequency. THD is used to characterize the linearity of audio systems and the power quality of electric power systems.
 
The specification for Total Harmonic Distortion is one that compares input and output audio signals, with the difference in stages measured as a percentage. So you might see a THD listed as 0.02 percent with specified conditions of frequency and equivalent voltage in parenthesis after it (e.g. 1 kHz 1 Vrms). There is indeed a bit of math involved to calculate Total Harmonic Distortion, but all one needs to understand is that the percentage represents the harmonic distortion or deviation of the output signal – lower percentages are better. Remember, an output signal is a reproduction and never a perfect copy of the input, especially when multiple components are involved in an audio system.
 
This Webinar will compare the signals on a graph, and further describe the rational regarding the slight differences while exploring the depths of “THD”.
 
 

Course Number:  LWP110422
Field of Study: Electrical
Level: Basic
Presenter:
Ronald Finger
Prerequisites: 
None