offline analysis - matlab & bci

Forum for discussion on different signal processing algorithms
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tracy
Posts: 1
Joined: 03 Aug 2009, 21:13

offline analysis - matlab & bci

Post by tracy » 03 Aug 2009, 21:23

hi,
i have 2 questions:

1. how strict is the 9-36hz rule for selecting optimal frequencies
2. is it a 2hz band in a 3hz band in the matrix classifier.

i performed an offline analysis of teh initial session, and found the greatest difference with both feet at Cz at 8hz. when i then put this info in the edit matrix, i had to drop the hz to 6hz before it would work. can you help me understand this, and then how to deal with this, choosing either going up in hz or lower in hz if it won't function with the hz found to be the best.

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

frequency questions ...

Post by gschalk » 04 Aug 2009, 11:18

Tracy,

I have some difficulty understanding your questions. Regarding the question with the optimal frequencies, does this correspond to what frequencies are appropriate for mu/beta rhythm-operation of a BCI?

I do not really understand the second question, but the frequencies are computed in certain bins, e.g., 2 or 3 Hz bins, depending on how to configure it. In the classifier, you can only refer to frequencies that are actually computed. E.g., if you start at 6 Hz with a bin width of 3 Hz, you cannot get an 8 Hz frequency. Please check out the documentation on

http://www.bci2000.org/wiki/index.php/U ... e:ARFilter

I hope this helps.
Gerv

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