[Eeglablist] question about shieldroom specifications

[Makoto Miyakoshi]

Dear Archana,

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.

Makoto



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
>
> Best,
> Archana
>
>
>
>
> __________________________________________
> 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
> To unsubscribe, send an empty email to
> eeglablist-unsubscribe at sccn.ucsd.edu
> For digest mode, send an email with the subject "set digest mime" to
> eeglablist-request at sccn.ucsd.edu
>



-- 
Makoto Miyakoshi
Swartz Center for Computational Neuroscience
Institute for Neural Computation, University of California San Diego
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://sccn.ucsd.edu/pipermail/eeglablist/attachments/20141016/827db2ba/attachment.html>