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Re: TinyEEG update

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  • sleeper75se
    Hi all, today I did some tests on the whole system. http://groups.yahoo.com/group/buildcheapeeg/files/hardware% 20design/TinyEEG%20-%20SMT/Test%20results/
    Message 1 of 13 , Apr 30, 2002
      Hi all, today I did some tests on the whole system.

      http://groups.yahoo.com/group/buildcheapeeg/files/hardware%
      20design/TinyEEG%20-%20SMT/Test%20results/

      Connecting 100k, 1meg or 10meg to ground produdced too much 50Hz
      interference to be reliable, so I have not created any images of
      that. It looked like a lot of noise on top of the 50Hz signal though.
      50-100 microvolt perhaps... Did I observe the current noise caused by
      amplifiers, or something else?

      I could not see any 'motorboating' oscillations today, perhaps it was
      caused by a ground loop in my previous test setup? I am not using
      optical isolation yet, because I am still waiting for parts I have
      ordered.

      Anyway, the digital section (12-bit AD converter + microcontroller)
      works great, but I'm still wary about the EEG-amplifier.

      By the way, I had some problems with the serial port on the new
      computer in the lab. The motherboard uses the nforce-chipset from
      Nvidia... I could read data for a few seconds, but then it would stop
      coming. When I restarted my program, it worked again. I had to resort
      to using an RS232-to-USB converter to make it work. I can only assume
      it is a bug in their chipset or chipset driver, as it works fine with
      my own computer, running the same OS (win2k) ;o)

      Regards,

      Andreas
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