about ADC testing problem

[lhlbluesky]

adc testing dac

in ADC testing,usually a N-bit ADC(device under test) is followed by a N+2-bit

DAC to get the reconstructed analogue value, then to PC for further analysis.

then i want to ask, if N is very very large, then how to find the N+2-bit DAC, or

how to realize a high enough resolution DAC simply?

thanks all.

 

[lhlbluesky]

difference between dac tests and adc tests

someone says we can use an offset-adjustable low-resolution dac, by adjusting the offset voltage by LSB/4, the resolution can increase by two bits, but why? how to understand the above words? who can help me?

 

[Petre Petrov]

adc testing

Hello!
It seems tome that there is something wrong in your explanation.
As far as understand your problem, you are in need of DAC with at least two more Accurate bits than the bits in ADC, not with two more bits of Resolution.
There is a difference between "accuracy" and "resolution".
For example if you use two 8-bits DACs MC1408 you could produce a 16-bit DAC with approximately 16 bits of resolution but the accuracy will still approximately 8 bits.
Ref:
http://www.515ic.com/View-55.html
Size: 117KB , MC1408-8.pdf (page 6)
The best solution is to use a single DAC with at least two more accurate bits.
I hope that is helpful, but you need still to reformulate your problem
BR
Petre Petrov

 

[eecs4ever]

"in ADC testing,usually a N-bit ADC(device under test) is followed by a N+2-bit

DAC to get the reconstructed analogue value, then to PC for further analysis. "

ADC-->DAC---> PC ? this doesnt make sense to me. DAC outputs an ANALOG value which the PC needs to read... with an even higher resolution ADC ?

It's much more feasible to construct the loop this way

PC--> DAC-->ADC --(DIGITAL Data)--> back to PC

There are limits to DAC resolutions, so for really high resolution ADC testing, don't use a DAC.


Analog Sine Wave --->Bandpass Filter --> ADC---> PC.