[EEG] Useful EEG frontend electronics article, connector information

[Albert Alexander]

Hi all,

I found a great article on noise and circuit design for EEG. Definitely
worth reading in entirety:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2817545/pdf/CIN2010-630649.pdf

Also, that Amphenol connector (24-28s) is standard and available, but is $45
a pop. May be wiser to cannibalize that connector that heads to the needles.

Regarding noise/EMI:

At low frequencies, magnetic fields are a much bigger issue than electric
fields. Magnetic fields are tremendously difficult to shield, especially
when one end of the shield is open (the electrode cap). I think shielding
for the electrode leads is probably not going to be very helpful. Unless we
put the electrode cap inside a metal helmet, which might be pretty sweet.

We should DEFINITELY twist the plus with the return wire for each of the
leads. This should reduce 60 Hz AC noise substantially. It'll help with
fluorescent light switching noise, but that stuff is just plain hard to deal
with.

What type of noise have you guys seen on previous readings? Is it mostly
high frequency? Is there much DC offset for your input signals? If you have
data available I'd love to see it.

Best regards,
Albert
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