Coherent sources

[Robert Oostenveld]

Hi Sreenivasan

The bandpass filter options in timelockanalysis have the same config as
those in preprocessing. If you open timelockanalysis in the editor, and
jump to the first comments after the initial help block (in my version
it is around line 42), you will see

% Undocumented options:
%   cfg.blc                = 'no' or 'yes'
%   cfg.blcwindow          = [begin end]
%   cfg.bpfilter           = 'no' or 'yes'
%   cfg.bpfreq             = [low high]
%   cfg.bpfiltord          = number giving the filter order
%   cfg.bpfilttype         = 'but' or 'fir'
% The filtering options are supported here only to compute the
covariance
% matrix in a specific frequency band while avoiding to do the
preprocessing many times.

I guess that that should suffice as explanation. Maybe some extra words
on why they are hidden as option: in preprocessing you can pad the
trial data with some extra data that also is read from the (continuous)
file. After this (optional) padding, the data is filtered. That means
that any filter artifacts will occur in the padded begin and end of the
datasegment, and those "pads" are again removed after filtering. In
timelockanalysis  it is not possible to pad the data any more, hence
filtering should preferably done when as much of the data is present.

best regards,
Robert


On 4 Nov 2004, at 20:57, R. Sreenivasan wrote:

> Hi Robert,
>
> I find it difficult to figure out the hidden option of the frequency in
> timelockanalysis. Would you please send me a sample script?
>
> Thanks
> Best regards, Sreenivasan

----------------------------------------------------------------------
Robert Oostenveld, PhD
Center for Sensory-Motor Interaction (SMI)
Aalborg University, Denmark

and

F.C. Donders Centre for Cognitive Neuroimaging
University Nijmegen
P.O. Box 9101
NL-6500 AH Nijmegen
The Netherlands

Tel: +31 (0)24 3619695
Fax: +31 (0)24 3610989
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