Hi Francois,
I computed spectra using the psd welch process for two conditions, and then estimated their difference using the difference (A-B) process. Unlike for the spectra themselves, the spectra difference cannot be visualized with Power/Magnitute/Log(power) and the units are incorrect (fT).
Thank you,
Dimitrios
Hi Dimitrios,
Sorry for the response delay...
The process Difference A-B sets the field Measure to 'other', discarding the measure initially applied to the values (power, magnitude, log, phase or none). The information about how to interpret the data being missing, we don't know how to transform the values to log or magnitude.
The initial logic, I think, was to avoid representing differences as log, or to transform differences of power into magnitude (sqrt of negative values). But on the other hand, this prevents from displaying correctly these differences, as you reported.
I pushed two commits to remove this Measure field reset, from the process Difference A-B and Weighted difference A-B:
Do you think this fully address the problem without causing other side problems?
@Marc.Lalancette @Raymundo.Cassani @hossein27en
Can you imagine cases where not resetting these fields can be more harmful than beneficial?
Would you have other suggestions?
Hi,
Would it be better to use ratio for powers? Something like "Difference" A/B