Improved Static Testing of A/D Converters for DC Measurements

A new method is presented for the calibration and the linearity testing of analog-to-digital converters (ADCs) and dc digital instruments, such as digital voltmeters (DVMs). The test is truly static, because it uses only dc voltages with a small superimposed noise (dithering). It is much faster than that described in the IEEE Standard 1057/94 since it uses a minimal number of test signals and acquired samples in a theoretically nearly optimal manner, i.e., maximum-likelihood estimation. In addition, contrary to the test described in the IEEE Standard 1241/00, it allows offline measurements and testing of stand-alone instruments, such as DVMs. Another advantage of the proposed method is that the resolution requirements for the source of test signals are relaxed. After a review of the state of the art, this paper provides the mathematical derivation of the employed estimator. Simulations, theoretical analyses, and experimental results are also provided to illustrate the performances of the proposed test method.