Set unit to microvolts

[Clemens Brunner]

It seems like it is currently not possible to set the resolution and unit independently. As soon as resolution <= -7 (which is True for the default), the unit is set to nV.

However, I just had a conversation with a BrainProducts developer regarding potential issues with the unit. Specifically, he said that BrainVision Analyzer currently expects the unit to be µV. If it's something else, auto-scaling doesn't work (at least the initial view).

Therefore, I would like to suggest to add an option that controls the unit. Possible values could include 'V', 'mV', 'uV', 'µV', and 'nV'. I would set the default to 'uV' (which is also the expected unit if the unit field in the exported file is empty).

[Clemens Brunner]

There could also be an 'auto' value, which would replicate the current behavior.

[Stefan Appelhoff]

Hi @cbrnr ... always good to get some info from Brain Products. Thanks for reporting the potential issue :-)

I think your suggestion is reasonable, especially when 'auto' is added as an option.

@tstenner implemented that current behavior, perhaps he has something to say about this.

[Tristan Stenner]

The PRs in question (#17 and #20) will have their anniversary in less than a month so I don't recall the exact reasoning, but I think giving the scale in µV uses more digits for the same precision or cuts off more digits than I was comfortable with.