Accuracy Increase of Discrete Sensors With Time Delay

Abstract

The discrete sensors of continuous physical quantities are widely used in various technical systems. Real sensors have a considerable inertia and they operate in the conditions of random noises, therefore, they include the analog-to-digital interface. This interface creates discrete values of the input signal and suppresses the influence of random noises almost completely with application of the antialiasing filter. However, the discrete values are formed on the output of the analog-to-digital interface with some time delay. Therefore, the digital sensors have a large error, caused by this delay. In this article to eliminate this error an astatic high-speed discrete corrector is proposed. The error of the corrected discrete sensor is equal to zero at the steady-state mode, if the degree of the input polynomial signal is one unit less than the astatism order of the used corrector. It is supposed that the time delay of the discrete sensor is multiple to the sampling period of the analog-to-digital interface. To determine transfer functions of the discrete sensor and the astatic discrete corrector the formulas are obtained. The operation algorithm of the astatic high-speed discrete corrector is determined on the basis of its transfer function. The efficiency and feasibility with application of digital device of the proposed corrector is illustrated by the example of the sensor design with the astatism of the second order. The obtained results can be used in the development of highly precise discrete sensors of various physical quantities.