After calculating PSD using Welch's method for MEG data, the identical unit is used for magnetometer and gradiometer. However, magnetometers measure in the unit [T] and gradiometers in the unit [T/m]. Should not then also the unit in the PSD differ or is corrected for this?
You can notice the same for the recordings, we use only the T units for the gradiometers. For displaying the MEG recordings interactively, we use a scaling factor to "convert" the gradiometers from T/m to T.
See this tutorial section: Tutorials/TutMindNeuromag - Brainstorm
However, this correction is not applied when applying processes on these recordings.
Therefore, the PSD is computed from the values in T/m, and the units displayed in the figure are incorrect.
@John_Mosher Is this correct?