I'm not sure whether the "raw" data that is written to the .csv file is already referenced to the SRB channel (which is linked to the earlobe electrode) or if I need to apply some reference method to it...
Yes, the default reference is SRB2. This is not a 'channel' per se, but a bus which acts as the other electrode for all the channel pins. The SRB2 electrode can be placed anywhere you desire, not just at the earlobe.
What is the referencing operation that is applied? That is, how are the values written to the .csv file computed in terms of the values measured by both electrodes (a channel and SRB2)?
EEG amplifiers are DIFFERENTIAL, measuring the microvolts between plus and minus electrodes. When you use SRB2, all the IN*P (IN1P, IN2P, etc.) pins are bussed together and appear on the SRB2 pin. Which is typically connected to one or both ear lobes. The IN*N (IN1N, IN2N, etc.) pins then connect to your head 10-20 sites.
I still do not understand. Let me give you an example: I have 1 electrode on the front of my head (FCz) and I have SRB2 connected to my earlobe and BIAS to the other earlobe. How is the value of FCz written in the .csv file computed? FCz - SRB2? FCz - BIAS?
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