Envelope Extraction in Origin

I'm doing "envelope extraction" analysis on my dHvA data. It took me some time to figure out which boxes to check or uncheck on the Origin FFT tool, so I thought I would just document that here, partially so that I remember how to do it myself.

While usually I would apply a window (e.g. "Hamming window") while doing FFT, here it's better to not use a window i.e. use the "Rectangular" window.

Forward FFT
Use "Rectangular Window"
Uncheck "Normalize Amplitude"
Check "Shift Results"

Apply filter

Backward FFT
Select real and imaginary columns
Use "Rectangular Window"
Uncheck "Normalize Amplitude"
Uncheck "Shift Results"

Plot 2*r
Results may be offset in x-direction.