This paper presents the modeling and the comparison of two acquisition systems developed at the Test Centre Division, European Space and Technology Centre, of the European Space Agency in the frame of two investigations: 1) on microelectromechanical- systems-based sensors for the detection of very low-g accelerations and 2) on the feasibility of a compact and low-power multisensor acquisition platform for environmental tests of spacecrafts or subsystems. A Simulink-based approach is proposed for fast, accurate, and reconfigurable modeling of both systems, taking into consideration the sensors and the acquisition chain. This paper aims to highlight the importance of the models as key tools to predict the distortion and noise sources, to allow fast setup of the experiments, and to manage the signal conditioning process. The validity of the proposed technique, applied to the two acquisition systems, is assessed by comparing the predicted results with tests on the real system. Finally, this paper aims to prove, by comparing the two approaches (dedicated acquisition system and multisensor acquisition platform), the importance of the characterization of the whole acquisition system when high performances need to be achieved