Résumé
Two AxC techniques have been successfully applied to hardware components. The first one is the functional approximation [1]that modifies the circuit structure replacing the original function F with the function G. G implementation leads to area/energy reduction at the cost of reduced accuracy, meaning that some errors can be observed at the outputs of G. The observed errors are a variation between the output values of F (precise) and G (approximate). The variation is the accuracy loss measured by means of quality metric(s) [1]. The second AxC technique is the over-scaling based approximation. Basically, the HW component is forced to work outside its specified operating conditions [1]. The classical example is the reduction of the supply voltage under the minimum value.