[Eeglablist] question about shieldroom specifications
mmiyakoshi at ucsd.edu
Thu Oct 16 16:09:40 PDT 2014
EEG signal range is 1-500Hz. Not even kiloHertz. Because of this, any
shield room is fine (i.e. does not work anyway).
The most problematic environmental artifact is 50/60Hz line noise. This is
hard to shield because of low frequency. I heard that you need a type of
magnetic shield instead of ordinary copper ones to shut it off.
I've seen labs that is not shielded. Their data tend to have higher 50/60Hz
line noise, but we can low-pass the data below that. Our Mobilab does not
have a shield either.
> I would like to know what does the cutoff in Hz represent.
The noise level is guaranteed to be attenuated to the specified levels.
On Wed, Oct 15, 2014 at 10:20 PM, Archana Singh <sine.arc at gmail.com> wrote:
> Dear All,
> I hope that some of you have experience with construction of electric
> shielding room for your EEG experiments. I am negotiating with shieldroom
> companies for our new EEG lab.
> I would like to know how to interpret the shielding cutoff specifications.
> I have received various shielding specifications as follows. I know 40dB
> would be sufficient for our purpose, but I would like to know what does the
> cutoff in Hz represent.
> 100K-30MHz / 40dB
> 10-30MHz / 80dB
> 500k-500MHz / 40dB
> Archana Singh,
> ERATO Researcher,
> Functional and Chemosensory brain imaging group
> Department of Applied Biological Chemistry
> Graduate School of Agricultural and Life Sciences
> The University of Tokyo, Tokyo 113-8657
> Eeglablist page: http://sccn.ucsd.edu/eeglab/eeglabmail.html
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Swartz Center for Computational Neuroscience
Institute for Neural Computation, University of California San Diego
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