Uncertainty Contribution of the Analog Conditioning Block in DSP-based Instruments

The type-B evaluation of the uncertainty affecting the measurements provided by any instrument could be done by properly processing the nominal accuracy specifications of each functional block in the instrument. In DSP-based measurements, the implementation of such a procedure faces the difficulty arising from the fact that the usual accuracy specifications of the input analog conditioning block cannot be used to determine the uncertainty affecting each sample of the block output signal. In this paper, a calibration procedure is proposed to tackle this issue. It is based on the use of high-accuracy data acquisition boards and the simultaneous acquisition of the signals at the input and output of the analog block. The results of the characterization of active voltage transducers are reported. An application example is developed and its results are discussed.