Comparative Analysis of the RMS Measurement Methods Based On the Averaging of the Squares of Samples

At present, the method based on averaging of the squares of samples is the most popular method for the measurement of the root mean square value (RMS). The article discusses the approaches associated with averaging the measurement time to the nearest integer sample and further clarifying the moment of transition of the input signal of a given level (the application of non-integer number of processed samples). In the latter case, an additional approximation of the signal is performed in the vicinity of the end of the measurement time by applying approximation polynomials of the zero and the first order. For each of the approaches under consideration, analytical expressions are obtained for calculation of the RMS measurement error. The obtained analytical results are confirmed by coincidence with the simulation results at reference points. Simulation mathematical modeling is performed by Matlab and Simulink software packages.