The smoothing post-processing function applies a running weighted average on the curve with a defined width. The width can be expressed in 1/n octave or linear terms. Two different weightings can be applied: rectangular or Hanning. The weighting is symmetrical around the middle point and doesn’t include zero end points. The smoothed curve has the same number of points as the original. The curve can have an uneven spacing in frequency domain, because interpolation is used. The smoothing is applied on power values (y^2) and unwrapped phases.
The curve end points are unchanged. To do this, a symmetrical reduction of smoothing width at the edges is used.