Calculate Total harmonic distortion with FFT

mactek

Hi

Can anyone help me out here, I am trying to calculate the total harmonic distortion measured (%) in a 50hz power system using my Hantek DSO1202B oscilioscope.

I have used the FFT function and displayed the harmonics for a sine wave , how do I calculate the THD ? ( can the scope do this  ?)

amy

The scope can't calculate the THD.
You can check the information online.
The information is as follows:
“THD of operational amplifier is the ratio of RMS value of each harmonic (2nd, 3rd... Nth) in the input signal of operational amplifier to RMS value of output signal fundamental when the input signal of operational amplifier is pure sine wave (i.e. sine wave without harmonic). In the actual test, n is generally taken as 6, because the amplitude of harmonic decreases rapidly with the increase of harmonic order. The sixth harmonic only accounts for a very small part of the total harmonic.”

mactek

thanks amy