Development of a Method for Measuring small Nonlinear Distortions of Periodic Electrical Signals

The paper proposes a method for measuring small nonlinear distortions of the shape of periodic electrical signals to assess the influence of higher harmonics in voltage and current signals on the serviceability of electrical radio equipment. The developed method is based on the modification of the exact formula for the harmonic coefficient using power series expansion in the range of its small values. The practical application of the method is studied on the basis of two variants of its implementation: analog and digital. One of the options for a simplified block diagram of a microprocessor-based meter for small values of the harmonic coefficient is proposed based on the developed method. The methodological error of measuring the harmonic coefficient in the region of its small values is investigated. It is shown that the proposed method for measuring small non-linear distortions of periodic electrical signals ensures the measurement of small values of the harmonic coefficient with an error of the order of tenths and hundredths of a percent.