From: Joerg Hansmann (info_at_jhansmann.de)
Date: 2001-05-17 20:03:33
Hi,
----- Original Message -----
From: Praveen Kumar <pkk7_at_y...>
To: <buildcheapeeg_at_yahoogroups.com>
Sent: Wednesday, May 16, 2001 7:20 PM
Subject: [buildcheapeeg] Sound Card-Summary
...
> 5. Cost advantage needs to be analysed. Joerge
> Hansmann is familiar with Hardware of microcontroller
> based system as well as the hardware required to be
> used with the sound card. I think he will be the righ
> person to comment upon it.
The active components required for the 6-channel time multiplex
modulator would be:
1x CA555, for generating the multiplexing time base
1x74HC191, 4 bit synchronous counter for generating glitchfree
circular mux-adresses 0..15
1xADG406/ADG506/MUX16, (or a cheaper type with 0..5V IO-Range),
1:16 channel analog multiplexer
1xTLC272 , OP-Amp for opto-isolator linearization
2x ??? , Optoisolators with _very_ precisely matched parameters
and very high isolation voltage (5500 V rms for IEC601-1)
These components+PC soundcard+decoder software(or driver software)
would replace a part of the AT90S4433 functionality. A digital feedback channel
for LED-goggels etc. or a tuneable calibration generator would not be provided.
The price of the modulator components could perhaps be 1/2 (only estimated)
of the AT90S4433. However I see a problem with the availability of the above
mentioned Optoisolators.
Regards ,
Joerg
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