Analog to Digital Converter

Jon Elson jonelson126 at
Sat Aug 15 20:41:46 CDT 2015

On 08/15/2015 11:18 AM, Douglas Taylor wrote:
> I have a number of laboratory instruments that are from the 1990 time 
> frame.  They produce digital data that is the digitized signal from a 
> detector, the data can be from 512 to 65K samples long.  The ADC used 
> in these instruments is a 16bit 100ksample/sec design.  The ADC is in 
> a 3 by 4 inch metal box with a row of pins on each long edge.
> I think some of them are failing because I get the full 16 bit 
> resolution from one machine, but not the others.  This was determined 
> by taking the digital samples and sorting the values and computing the 
> increments between the adjacent values.  In some cases the output 
> looked like 14 bit resolution and in one case 6 bit resolution.
> Does anyone have any experience with technology?
> Who was the manufacturer?  (There is no id on the outside)
> What is inside the box?  Is it a hybrid circuit?
DDC made a number of hybrid ADCs, but I've never seen one that was 3 x 
4"!  That's really big.  Most likely there is a normal PC board inside, 
with a bunch of chips and discrete components on it.  Is this box 
hermetic, or maybe if you peel back a label, there may be screws that 
hold it together.


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