Noisy Signal

Forum for discussion on different brain signals
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timo.veldt
Posts: 23
Joined: 12 Feb 2010, 04:08

Noisy Signal

Post by timo.veldt » 19 Mar 2010, 05:08

Yesterday I ran a demo of a BCI on an ICT-conference and I experienced a few problems there. The demonstration was given in a huge hall that was bustling with network activity, other computers, mobile phones and the like, which made our signal incredibly noisy.
Fortunately we were not the only one to experience this problem, a few of our direct neighbors also had problems with their EEG setups. We discussed the problem together and tried some different filters (low pass, high pass and notch filters) and found a setting that gave us better results.

However we were unable to set our programs to these frequencies (i.e. a low pass filter of 20 Hz.), which amounts to the following question. Why can't we set the values of signal source to all possible values?

We were using a BCI2000 setup with gTec's g.USBamp (v2.0) and the signal acquisition program supplied with BCI2000. Other groups were using Biosemi hardware and software.

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

USBamp

Post by gschalk » 19 Mar 2010, 11:58

Hi,

The USBamp does digital filtering in the DSP onboard. g.tec provides filtering coefficients for a number of possible filter settings, but not any arbitrary choice.

You can always filter signals in BCI2000 either just for display by right-clicking on the source display or by including an IIR filter in the source module.

Gerv

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