Shapes of Input Signals for the Calibration of Measuring System Intended for the Measurement of Dynamic Signals
Edward Layer
Abstract:
Calibrating signals for measuring systems intended for measurement of dynamic signals are generally limited to standard signals. The unit step input in time domain and sinusoidal signal in frequency domain are the most often applied here. However dynamic signals have in the practice quite arbitrary shapes which significantly differ from the standard signals. In consequence, the results of a calibration process realised by means of standard input signals are in practice useless, except of some very particular cases. On the other hand the process of calibration can not be realised by means of any dynamic signal because it is undefined and the set of such signals is infinite. In such a situation assumption that the calibration results have to ensure the mutual comparability of measuring systems is possible to attain only if the errors estimated in process of calibration receive maximum values. For this purpose the special class of calibrating signals maximising the assumed error criterion have to be applied. The results received then are similar to the class indexes resulting from the maximum static error determined for measuring instruments for static measurements. The paper presents the possible shapes of input signals which maximise integral-square-error criterion on the output of linear time invariant measuring system and its standard. In such a way a situation in which all the possible dynamic signals which might occur at the input of a real system are taken into consideration at the same time. The advantage of the presented method is the possibility of making the calibration process independent of the input signal shape through the application of signals which maximize the chosen error criterion.
Keywords:
dynamics of signals, integral-square-error criterion, matching of input
