problems with high pass filter

[Ingrid Nieuwenhuis]

Dear Susana,

 

Probably you data(segments) are too short for this setting. For the high
pass filter with 0.05Hz to work you need very long data (0.05 Hz is a cycle
of 20 seconds!), Do you need such low frequencies in your data? If not you
could try f.i. 0.5Hz.

 

Hope this helps,

Ingrid 

 

------------------------------------

Ingrid L.C. Nieuwenhuis

PhD student

Donders Institute for Brain, Cognition and Behaviour,

Centre for Cognitive Neuroimaging

Radboud University Nijmegen, The Netherlands

Email: ingrid.nieuwenhuis at donders.ru.nl

Tel: 0031 (0)24 - 36 10887

  _____  

From: FieldTrip discussion list [mailto:FIELDTRIP at NIC.SURFNET.NL] On Behalf
Of Susana Araújo
Sent: Tuesday, January 26, 2010 2:53 PM
To: FIELDTRIP at NIC.SURFNET.NL
Subject: [FIELDTRIP] problems with high pass filter

 

Dear all,

 

I’m analysing EEG data from children and I tried to set the high pass filter
to 0.05Hz (PreProcessing). However I get a warning message “Matrix is close
to singular or badly scaled.  Results may be inaccurate. RCOND =
6.669240e-017”.

Does anyone can help me to solve this problem?

Thanks a lot!

 

 

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EEG analysis.

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----------------------------------
The aim of this list is to facilitate the discussion between users of the FieldTrip  toolbox, to share experiences and to discuss new ideas for MEG and EEG analysis. See also http://listserv.surfnet.nl/archives/fieldtrip.html and http://www.ru.nl/neuroimaging/fieldtrip.
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