big voltage value

[marialaura]

Hi,

I read careful what you suggest on http://sccn.ucsd.edu/pipermail/eeglabli ... 00930.html as regard as the reference electrodes.

For my experiment I have chosen to put CMS/DLR on the ears. So If I understood this means that the voltage I measure on Cz is the difference between the voltage on Cz and the mean voltage (CMS+DLR)....am I right?

I tried then to analyze the bdf file with the eeglab software. I would like to know if when I visualize the EEG signal through the Channal data Scroll is right to read on the different channels value like 13441,3506 or -24678,3301. Sometimes are negative and sometimes are positive, but what really upset me is the value. Can I have such microvolt value if the subject is just in the resting period?
Can it be related to noise?

Thank you in advance.

[Coen]

The ActiveTwo is a DC system, the EEG is superimposed on electrode offset voltages, see http://www.biosemi.com/faq/24bitsystem.htm . DC values of +13 mV and -25 mV as in the above examples are very normal.

Best regards, Coen