Problem with maximum number of channels

This forum deals with BCI2000 configuration issues.
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M_Spueler
Posts: 3
Joined: 26 Sep 2007, 07:26

Problem with maximum number of channels

Post by M_Spueler » 26 Sep 2007, 08:02

Hello,

currently, we're playing around with BCI2000 and a 275channel-MEG. But we only get it running with a channel subset of at most 128 channels. It's the same problem using Neuroscan and RandomNumber as Source-Module. For SignalProcessing we use the MatlabSignalProcessing...

If I set TransmitCh to 275 i have to adjust SpatialFilteredChannels and the SpatialFilterMatrix accordingly!? Problem is with matrix. The Gui allows only a maximum of 256 columns. But if there are more than 128, i get following error :

Code: Select all

26.09.2007 13:57:33 -  SpatialFilter: A necessary condition is violated. Please make sure that the following is true: Parameter( "SpatialFilterKernal" )->GetNumValuesDimension1() <= MAX_M.
26.09.2007 13:57:33 -  SpatialFilter: A necessary condition is violated. Please make sure that the following is true: Parameter( "SpatialFilterKernal" )->GetNumValuesDimension2() <= MAX_N.
Did i miss any options or is there another way to get 275 channels working ?

thanks in advance

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

Channel problems ...

Post by gschalk » 26 Sep 2007, 09:23

Hi,

Did you use the most recent version of BCI2000 that is on SVN? Several years ago, we have been using the system with 144 channels and I do not remember any issues.

If you are using an old version of BCI2000 (i.e., more than 1 year old), please upgrade to the most recent version on SVN. If you are using the most recent version, you have to options: 1) either simply search the code for the MAX_M and MAX_N definitions, increase them to a larger number, and then recompile; 2) upgrade to BCI2000 v2.0, which is available on the SVN under \branches\bci2000.v2.0. We will release this version only after the documentation is complete, but the code if fully functional right now.

Gerv

M_Spueler
Posts: 3
Joined: 26 Sep 2007, 07:26

Post by M_Spueler » 26 Sep 2007, 12:01

thanks for the reply. I forgot to mention ... I'm using V1.41 at the moment. But I'll try the SVN Version ...

mellinger
Posts: 1114
Joined: 12 Feb 2003, 11:06

Post by mellinger » 22 Feb 2008, 10:26

As of SVN revision 1809, the 256 columns limit has been removed from the GUI (the limit is now 32767).

Thank you for reporting this issue.

Juergen

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