Hello. I have a problem with my Analog Discovery 2, and it's existing since i received it. I wanted to test the device parameters and simply plugged W1 output to 1+ scope input. Twisted 1+ and 1- cables and shorted 1- input to ground. The measured NF is quite ok (but i thought it would be better) - it's around -91dBV. But THD is really high. I'm measuring a CABLE so there should be no distortion and I receive around -70dB dBV THD (so it's around 0,03%). The output waveform is 1kHz sine, amplitude of 2V. I use spectrum analiser with averaging on, I've set the highest range (50V) - using maximum range helped a bit but i'm still not there. The frequency range is 10Hz - 50kHz. Couple of screenshots should picture the problem.
Are my settings wrong? Is waveform generator not precise enough? Is the input somehow clipping - if yes, why? Is Analog Discovery 2 simply not capable of measuring THD lower than -70dB?
I also marked with light blue circle a lot of artifacts on the spectrum - what's that?!
Thanks for the answer and have a nice day.