[Eeglablist] BDF data range

[Quentin Noirhomme]

Dear all,

Two questions on the BDF data range:

- After opening  a bdf file recorded with Biosemi in EEGlab
EEG = pop_readbdf(filename);
what is the range of the data in EEG.data ? Are they between physical min
and physical max or between digital min and digital max ?

- While checking the BIOSIG files, I realised than sometimes the bdf data
are multiplied by the gain :
(physmax -physmin) ./ (digmax - digmin)
and sometimes they are multiplied by the gain and then the following
factor is added:
physmin - digmin*gain

This depends on a flag but I did not go far enough to understand the flag.
The first solution was also proposed recently on this list.
Why such a difference ?

Thanks in advance for any answer,

Quentin