Determining Dynamic Characteristics of Measuring Instruments with a Spectral Method Insensitive to Harmonic Interference

Determination of the dynamic characteristics of measuring instruments based on experimental transient characteristics is associated with the problem of consideration of their inherent interferences having various origins. The presence of broadband harmonic interference, especially of a high level, can reduce the accuracy of determining the desired dynamic characteristics of measuring instruments. The purpose of this work was to demonstrate the capabilities of the spectral method for finding individual dynamic characteristics of measuring instruments using transient characteristics containing high-level harmonic interference. It is shown that the imaginary part of the complex spectral density of signal formed according to the proposed rules from the transition characteristic is insensitive to harmonic interference of any level in any frequency range. It is proposed to use this imaginary part to determine the coefficients of the desired dynamic characteristics, for example, using regression analysis. The work is illustrated by examples of spectral characteristics of signals with and without harmonic interference.