Uncertainty Issues in Multi-Channel Data Acquisition Systems.

This paper deals with the analysis of multi-channel data-acquisition systems with the aim of identifying and combining the main uncertainty contributions. The approach based on the GUM uncertainty framework has been implemented to characterize and combine the different contributions. Particular attention has been paid towards cross-talk effects, which can be not negligible above all in multiplexed data-acquisition systems. The uncertainty analysis is described for a commercial data acquisition board, whose cross-talk specification is not suitable for a reliable uncertainty estimation in operating conditions. For this reason, an experimental characterization of the board has been performed and the obtained results are provided. These results highlight that a proper characterization of a data-acquisition system is effective in estimating the actual performance at the operating frequency and provide valuable information in terms of source resistance and input-channel configuration that make cross-talk effects negligible.