PCE Health and Fitness PCE-GPA 62 User Manual page 22

%THD-F: Total Harmonic Distortion with respect to Fundamental frequency
%THD-F = ( √ (V2
2 2
+ ... +V49
+ V3
Where,
V1: magnitude at the nominal frequency (eg.50 or 60 Hz)
V2: magnitude at the second harmonics
...
V50: magnitude at the 50-th harmonics.
2 2)
+ V50 ) / V1) * 100
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