Search found 10 matches

by Seung-Chan Lee
13 Dec 2011, 04:52
Forum: BCI Systems - Signal Processing
Topic: I need a mathematical understanding of r2 value.
Replies: 2
Views: 3529

I need a mathematical understanding of r2 value.

Hi. I am user of BCI2000 and I used BCI2000 offline analysis GUI. This GUI used r2 value for finding EEG signal features. But, I cannot understand r2 value yet. I read the thesis.pdf which written by Gerwin Shalk. In this document, I can find the r2 value definition. But, I think it's definition is ...
by Seung-Chan Lee
09 Aug 2010, 08:29
Forum: BCI Systems - Signal Processing
Topic: Offline analysis.
Replies: 12
Views: 5473

Thank you for response. I have another question about calculation.
I don't know how can that value(3500 muV/sqrt(Hz)) be calculated?
How to determine that value?
I want to know process of calculation (or calculation step).
by Seung-Chan Lee
04 Aug 2010, 11:19
Forum: BCI Systems - Signal Processing
Topic: Offline analysis.
Replies: 12
Views: 5473

I am sorry about mistake in my sentence. Actually, the range of EEG signal is 10-100uV. But the maximum value of Spectra Channel plot is almost 70000uV/square(Hz). In spite of the small range of EEG signal, how do big value (70000uV/square(Hz)) can be calculated? And what is meaning of 70000uV/squar...
by Seung-Chan Lee
04 Aug 2010, 10:12
Forum: BCI Systems - Signal Processing
Topic: Offline analysis.
Replies: 12
Views: 5473

Hi. Thank you for your response. I have a another question about spectra channel plot. In our result, the maximum value of spectra channel plot is about 70000. I wonder how to calculate spectra channel value. And what is mean of spectra channel value. I don't know why we adjust spectrum would be 350...
by Seung-Chan Lee
27 Jul 2010, 00:04
Forum: BCI Systems - Signal Processing
Topic: Offline analysis.
Replies: 12
Views: 5473

I have a another question about spectra channel plot. Here is offline analysis result and spectra channel plot is just right down. http://infonet.gist.ac.kr/twiki/pub/lsc/1.jpg I wonder that what is the mean of Y axis of spectra channel 6 plot. The maximum value of Y axis is approximately 70000. How...
by Seung-Chan Lee
22 Jul 2010, 11:40
Forum: BCI Systems - Brain Signals
Topic: Signal generator and offline analysis
Replies: 3
Views: 6052

What is the role of the CAR filter?

Hello.

Thank you for response of the previous question.
I have a another question about CAR filter.
If high r2 value of the other channels caused by CAR filter, why is that?
And what is the role of the CAR filter?
How does the CAR filter affect the signal?

Please reply again. Thanks.
by Seung-Chan Lee
22 Jul 2010, 11:17
Forum: BCI Systems - Signal Processing
Topic: Offline analysis.
Replies: 12
Views: 5473

Hello. Thank you for your reponse Adam. I am coworker with Young Hak Shin. I would like to explain our hardware setting. First, we used TDT RZ2 processor and PZ3 low impedance amplifier. But, We do not use the headstage. Since we do not use headstage, So acording to your guidence, we use 1000000 TDT...
by Seung-Chan Lee
20 Jul 2010, 00:27
Forum: BCI Systems - Brain Signals
Topic: Signal generator and offline analysis Second question.
Replies: 2
Views: 4033

Yes. I add a noise.
Here is signal generator parameters.
Adding noise level is 30muV.
But, I still think that the 0-8Hz R2 values must be lower.
Why is that?

Image
by Seung-Chan Lee
19 Jul 2010, 10:22
Forum: BCI Systems - Brain Signals
Topic: Signal generator and offline analysis Second question.
Replies: 2
Views: 4033

Signal generator and offline analysis Second question.

Hello. all. :o Thank you for your reponse about previous question. I have a second question about offline analysis. Following the reply, I am NOT used CAR spatial filter. So, I almost solved that problem. This is CAR filter ON result. http://infonet.gist.ac.kr/twiki/pub/lsc/0vs1.jpg And, This is CAR...
by Seung-Chan Lee
16 Jul 2010, 10:42
Forum: BCI Systems - Brain Signals
Topic: Signal generator and offline analysis
Replies: 3
Views: 6052

Signal generator and offline analysis

Hello. all. :o I am a new member in BBS and this is first question. I have a question about using signal generator and offline analysis. Currently, our lab is focused on cursor task in BCI2000. To verify experiment setup, I used the signal generator and offline analysis and used follow modules. Sour...