Signal, Data, and Information in Physical Measurements

Problems of acquiring information on physical phenomena are reviewed. Special attention is concentrated on analyzing the mapping process, both the action and perception of signals and their further discretization. Possible shapes and parameters of signals in the interaction processes in the microcosm are discussed on the basis of the threshold and upper limit information relations. Since a perceived signal is determined with nonremovable inaccuracy, it is shown how to derive the main equations for the amount of data and information contained in them through analysis of integer variables, without resorting to the classical mathematical concepts of infinitesimals and infinite procedures. The main practical methods of information coding are briefly described.