[sdiy] modern AD/DA chips?

[Grant Richter]

If you look up a physics website, it will say the very best physical  
measurements made under the best lab conditions are lucky to reach 1  
part per million absolute accuracy.

That would be only 2^20 bits that could point to real world  
measurements (discounting errors in the DAC).

Bits higher than that usually are used for noise shaping or other  
math fanciness.

So what's the deal with all these high bit count ADCs and the like if  
they don't actually measure anything?

Do you just average the LSBs to get that single real 2^20 bit?



On May 6, 2009, at 6:53 AM, Paul Perry wrote:

>
> ----- Original Message -----From: "Tom Wiltshire"
>> Another approach would be to use two DACs with less resolution to   
>> create one of higher resolution.
>
> You can get more decimal places this way, but not more accuracy.
> If you put two 6 digit DACs together, the guaranteed accuracy is  
> still no better than 6 bits.
>
> That is why a 12 bit DAC costs mre than twice as much as a 6 bit DAC.
>
> paul perry Melbourne Australia
>
>
>
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