From: Jim Peters (jim_at_uazu.net)
Date: 2002-01-23 22:11:30
Jim Meissner wrote:
> Jim Peters ( on this group ) is at this time working on the idea you
> presented about frequency shifting. He is very excited about it.
> If he is successful, that method only solves the simplest of
> problems.
No, no, what I'm working on is for audio feedback, to let you listen
to brain-wave data that you already have in the computer. I'm
assuming that the data will come in over the serial port.
I gave up on the idea of using soundcard input after the discussions
with Andreas on the list. The problems are as follows:
- Everyone would need a full duplex sound card if we're going to do
audio output at the same time (e.g. for feedback).
- The electronics to do a pitch-shift (e.g. by amplitude modulation)
to drive this aren't trivial, but ask Andreas, because I know
nothing about electronics.
- There are problems with isolation (as Jim pointed out)
- We're stuck with two channels forever.
Also, there would need to be some extra processing on the input side
(but this is not too hard). Some people complained about the increase
in the amount of data to store, but that is not a valid criticism
because after processing, you would end up with a 128Hz or 256Hz
stream of data just the same as with serial input.
As it is, the hardware guys seem to be well ahead on the design of a
serial-based solution, so it seems much better to encourage this and
get something working than to waste energy on another approach.
Jim
-- Jim Peters (_)/=\~/_(_) Uazú (_) /=\ ~/_ (_) jim@ (_) /=\ ~/_ (_) www. uazu.net (_) ____ /=\ ____ ~/_ ____ (_) uazu.net
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