a different input circuit

From: Anand John (deep_river79_at_y...)
Date: 2001-05-01 13:35:33


Hello everybody! My name is John and I'm a new member
to the group. Just wanted to share this schematic I
found on the net...check out the attachment. It seems
to be quite promising and the output of the circuit
could be fed directly to a soundcard for further
processing. I emailed Mr. Bernd Porr, the man who
engineered the circuit, and this is what he had to say
:

Dear John,
it can work with some sound cards. The problem is that
the interesting EEG frequencies are around 1Hz. Most
sound cards have a high-pass filter of around 20Hz
build in. If you can find a card without such a high
pass filter it could work. Take a sine wave generator
and send the signal to the card. Test the frequencies
from 0.1Hz to 40Hz. In this range the card should have
a flat response. The second problem is the sampling
rate: a sound card samples with a rather high sample
rate.

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