Distortion N/A

[bobkatz]

What I'm trying to do now is measure distortion of a power line! I have a wav recording I made of the power line using an attenuator and an input transformer into an interface. I can open this wav in the RTA. Currently it's in spectrum rather than bars... i can't seem to get it to display an opened wav as 1 octave bars, only as spectrum. Regardless, the spectrum looks appropriate in the RTA with a hill around 60 Hz and a rolloff in frequency response above it.

None of the smoothing options in the asterisk option seem to be working. Aha. If I make my smoothing choice in the main window it is reflected in the RTA window.

Distortion is N/A no matter what I pick. Is it possible that REW's RTA can only measure distortion of a live signal on its input?

 

[John Mulcahy]

When you open a WAV file in the RTA, or drag it onto the RTA, it will be processed according to the current RTA settings and saved as a measurement with those settings. Once the file has been processed and whilst on the RTA you can then change the mode to see how the data looks in any other mode you choose, then save that as a measurement. The smoothing choices on the RTA window are applied to data as it is received, they don't affect data that has already been captured, but as you have noted you can smooth the saved measurements.

WAV files are processed in the same way as live inputs, so if the signal has a dominant tone that will be used as the fundamental and the distortion will be shown, provided the Show distortion button is selected.

If you attach the WAV file I can check if there's anything about it that would prevent distortion capture.