[FieldTrip] Questions on High pass and Dft filtering

"Jörn M. Horschig" jm.horschig at donders.ru.nl
Thu Jun 28 16:45:54 CEST 2012

Hi Philipp,

> The padding ensures that we only filter out a narrow 1/10 Hz wide 
> frequency bin.

sure, I didn't think about that - that's a pretty good reason to use 
padding :) However, the estimation of the 50Hz noise will be biased by 
the padded samples. I don't like the dftfilter anyway, and I am not 
filtering either (the reason for me is that 50Hz noise should be 
invariant to the experimental effects. I mostly investigate TFRs).

>   but looking at averaged timelocked data for the subject, the data looks
>   identical to the result I get using no filter at all, i.e., contaminated by
>   strong line noise.

I'm gonna look into this to see whether it is a bug or not. I'll let you 
know soon.


Jörn M. Horschig
PhD Student
Donders Institute for Brain, Cognition and Behaviour
Centre for Cognitive Neuroimaging
Radboud University Nijmegen
Neuronal Oscillations Group

P.O. Box 9101
NL-6500 HB Nijmegen
The Netherlands

E-Mail: jm.horschig at donders.ru.nl
Tel:    +31-(0)24-36-68493
Web: http://www.ru.nl/donders

Visiting address:
Trigon, room 2.30
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