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https://designers-guide.org/forum/YaBB.pl Design >> Mixed-Signal Design >> resolution of ADC? https://designers-guide.org/forum/YaBB.pl?num=1148829008 Message started by chungmnig on May 28th, 2006, 8:10am |
Title: resolution of ADC? Post by chungmnig on May 28th, 2006, 8:10am Hi~~ If said a ADC has 12bits,then the reference voltage = 2V then the smallest can measured voltage = 2/(2^12) = 4.88mV (it means LSB) , and if reference voltage = 1 V --> 1/(2^12) = 2.44mV , so the reference voltage =1 can measure smaller voltage if ADC's bit =12 Is this statement is right? thanks~~~ |
Title: Re: resolution of ADC? Post by Marc Murphy on May 28th, 2006, 9:21am Yes. If you have a 4-bit converter and full-scale voltage is 10 V, the value of the LSB is 10/(2^4)=0.625 V. The highest value is 15, which translates to 9.375 V, or Fullscale - 1 LSB. I hope this eases your mind! :) Cheers, Marc |
Title: Re: resolution of ADC? Post by Paul on May 28th, 2006, 3:52pm Hi, yes, your statement is correct if your ADC is quantization noise limited. In many cases, the resolution may however be determined by the thermal noise level, in which case the lowest value to be measured is reference-independent. In that case, using the larger reference voltage maximizes your dynamic range (if we neglect distortion). Paul |
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