We have a thing that generates DDS sine waves, audio kind of range, and we want to production test all 12 channels. We figure we might measure distortion too. The question is how good a Rigol scope is as a distortion analyzer.
So I bandpass filtered my B+K function generator and made a pretty good sine wave. The reported scope 2nd and 3rd harmonics are down about 56 dB or so, plenty good enough.
My guys will actually slurp out the waveforms and do the FFTs in Python. We could do lots of points. Scopes do mediocre FFTs, but it looks like the basic Rigol acquisition is pretty good.