Re: Analog to Digital Converter

On 28 Mar 2007 18:39:23 -0700, Peter.Basta@xxxxxxxxx wrote:

Hi guys i am in the process of trying to figure out how and where to
start to build a Analog to digital converter for a project. I have
done some research and it seems that at the basic level its nothing
more that a pulse oscillator circuit followed by a comparator. The
specification i must stick with are :
1. max input freqeuncy 100khz
2. successive approx type with best guess centering
3. max bits are eight
4. max error of 1% at output

If anyone can direct me to some circuit diagrams or information, i
would appreicate it.

thanks
peter


Successive approximation types are built around a D/A
converter and comparator. You compare the input signal
to the output of the D/A. Toggle the MSB of the D/A and
if the D/A output is now too big (comparator switches) you
turn that bit back off. Continue for all bits.

You can build a dead-simple D/A for this from a simple
R-2R resistor ladder, driven by any decent CMOS
digital output. A buffered printer port on an old PC
works fine. Full discussion of this, and software to
run it, at
www.daqarta.com/lptx.htm

Best regards,


Bob Masta

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Scope, Spectrum, Spectrogram, Signal Generator
Science with your sound card!
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