From: sleeper75se (sleeper75se_at_yahoo.se)
Date: 2002-03-06 11:24:47
Hello people,
since there are a few more members here now that are into electronics
(biomedical, even), I might as well post a design that I have been
sitting on for quite some time...
It is a variation on the "sound-card" solution discussed previously,
but with a difference.
Rather than using the sound card's ADC, you use your own, and
transmit the sound digitally to the sound card via optical fiber.
Some specifications:
Two channels, a 24-bit (16 bits effective resolution) ADC (CS5360)
followed by an digital-audio interface transmitter (CS8405A) and an
optical transmitter (Toslink, TOTX173). There is no microcontroller
or any other programmable parts.
The sample rate is 48kHz since it's based on audio circuits, so
downsampling in software is necessary. By doing this you can get
higher resolution, perhaps 18 bits. It depends on the ADC's noise
spectrum if it works.
I would love to have comments from everyone, and it would be nice if
someone could take time to try to build it. The parts are fairly
cheap and the part count is very low. A ballpark figure is < $100,
not counting the sound card.
You will need a 12V lead-acid battery and a 5V linear regulator (7805
is fine) to power it, as it consumes > 100mA current.
Some experience with low noise PCB design and debugging skills are
essential. It is just a paper product right now, so it might not even
work ... :-)
The schematic is posted here:
http://groups.yahoo.com/group/buildcheapeeg/files/hardware%20design/
/Andreas
This archive was generated by hypermail 2.1.4 : 2002-07-27 12:28:39 BST