bci2000.org BBS

Hi,

I noticed a strange thing in the EEG source in BCI 2000. The EEG source visualization cursor is not moving with a constant speed. The window that appear in the visualization window is 2 seconds; however, sometimes all of a sudden the cursor moves much faster than that rate. Then after a while, it moves with the normal rate again. This keeps repeating over and over.

Please advise,
Thanks.

Nadoona,

From what you describe, it is possible that you are running a BCI2000 configuration that uses close to 100% of the processor. Please check in the Task Manager what the processor load is. It should be below 50%. In typical configurations, it's between 5-10%. If it is close to 100%, perhaps you are digitizing at really high rates. In this case, set VisualizeSourceDecimation to a higher number. Perhaps you are 'clocking' BCI2000 at a rate that is too high. This is determined by how large SampleBlockSize is in relationship to SampleRate. E.g., at a SampleBlockSize of 10 and a SampleRate of 1000Hz, the system would update the displays, cursor movement, signal processing, etc., 100 times per second.

Gerv

The sampling rate is 256 Hz and the sample block size is 32 or 64. So I think 4 or 8 updates per second should not cause that problem.

Please advise.

PS. Im using mobilab as the data acquisition source.

Thanks.

Nadoona,

What is the overall Processor Load? What is the Processor Load of each module?

Gerv