Distortion graph?

[bjs]

I find non-linear distortion as objectionable in many ways as linear distortion so was pleased to discover that REW can measure harmonic distortion based on a sine wave input.

I'm actually trying to do a range of frequencies and would like to see the combined results graphically. Conceptually that means sweeping the input frequency over a range and, for each frequency, plotting the relative strengths of the fundamental and its harmonics (which is currently captured in the tabular form).

Can REW do this? If not could it be added?

[Anthony]

As far as I know it's just the output when an input signal is approximately a sine wave. I know approximate, because, I can whistle a tone and hold it for a few seconds and it measures the distortion That's how I discovered this feature.

If there's a way to slow sweep or log individual points, I dont know how. Maybe John will chime in on how feasible this might be.

[JohnM]

It is on the list for a future release

[Ricci]

John,
That's good news. What about the possibility of doing mulitple sine waves at the same time like IMD testing? Like choosing to output 20hz, 32hz, and 50hz at the same time?

[JohnM]

Most things are possible, but there would need to be enough demand and a good reason, writing REW is a spare time activity and spare time is a rare thing nowadays

[bjs]

As I recall from tests I did years ago, speakers that measured well on standard THD tests also did well on IM tests so it might not be worth a lot of effort.