dirac16
Member level 5
The DNL/INL measurement in the following exemplary 3b ADC shows different results depending on which LSB unit is chosen. For the case of the Actual_LSB unit we get DNL=0 and INL=0 for all codes. This tells me that the actual TF has no linearity errors! However, for the case of the Ideal_LSB unit the DNL and INL take on non-zero values, where DNL[k]=-0.75 Ideal_LSB and INL[k]=-(k-1)*0.75 Ideal_LSB for k=1,2,...,6. Though DNL is greater than -1 Ideal_LSB and apparently causes no missing codes, the INL grows up as a function of the code in this particular example. This tells me that the actual TF is very nonlinear! So which DNL/INL measurement is actually correct?