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This example compares the result of the total harmonic distortion (THD) with respect to the fundamental wave and with respect to the total root mean square (RMS). In this simulation model a non-sinusoidal voltage wave form is created by the superposition two voltage waves:

• Fundamental wave with RMS voltage V1 and frequency f1
• Third harmonic wave with RMS voltage V3 and frequency 3*f1

This simulation model compares numerically determined THD values with results, obtained by theoretical calculations:

• Compare the numerically determined THD value thd1.y and the theoretical value THD1, both with respect to the fundamental wave; also plot thd1.valid
• Compare the numerically determined THD value thdRMS.y and the theoretical value THDrms, both with respect to the RMS value; also plot thdRMS.valid

f1	Value: 50 Type: Frequency (Hz) Description: Fundamental wave frequency
V1	Value: 100 Type: Voltage (V) Description: Fundamental wave RMS voltage
V3	Value: 20 Type: Voltage (V) Description: Third harmonic wave RMS voltage
THD1	Value: V3 / V1 Type: Real Description: Theoretically obtained THD with respect to fundamental wave
THDrms	Value: V3 / sqrt(V1 ^ 2 + V3 ^ 2) Type: Real Description: Theoretically obtained THD with respect to RMS