Amplification of BCI2000 System EEG Signals

Forum for discussion on different signal processing algorithms
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sgupta
Posts: 1
Joined: 15 Sep 2004, 07:51

Amplification of BCI2000 System EEG Signals

Post by sgupta » 16 Sep 2004, 12:19

I have the dataset IIa from BCI Competition 2003. I would like to know that what will I have todo to get the absolute values of EEG signals in microVolts. I have read that the amplification used for this dataset was 20000. Does that mean simply dividing the signal values by 20000 would give me absolute values ?

Please help....

gschalk
Posts: 615
Joined: 28 Jan 2003, 12:37

Conversion factor ...

Post by gschalk » 22 Sep 2004, 12:58

Hi,

The numbers are in units of A/D units. The conversion factor to micro Volts is 0.008.

I hope this helps,
Gerv

faisal1
Posts: 12
Joined: 16 Jun 2008, 16:57

Post by faisal1 » 17 Jun 2008, 17:32

hi gerv,

i have a dataset collected from the EEG machine having Fs=200hz, and amplication of 10000 . How i could the absolute value of EEG data.

Is their any const value to multiply , and if so How could we calculate it????

Regards
Faisal

gschalk
Posts: 615
Joined: 28 Jan 2003, 12:37

data acquisition ...

Post by gschalk » 17 Jun 2008, 21:04

Faisal,

This completely depends on the bit resolution of your A/D converter and the input range of your A/D card/EEG system. The easiest thing is if you acquire a signal with a known amplitude, and then see how large it is. This will determine the conversion factor.

Gerv

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