I want to plot in the scope the FFT of my sinus signal with perturbations at 50KHz. In comparison with a perfect sinus at 50Hz, the Plecs result is identical whereas I should have one harmonics at 50kHz. How can I solve it?

Hello,

This is probably because of your FFT settings. If you set the base frequency (f) as 50 Hz, then to see a harmonic at 50 kHz, you need to set the number of Fourier coefficients (N) to at least a 1000 or higher. Please see the attached example.

Regards,

Manu

FFT.plecs (5.77 KB)

Thanks for your answer, my setting was ok. It was coming from my input signal. The command were wrong and my FFT was correct. Sorry