ON IMPROVEMENT OF SAMPLING TECHNIQUE DESIGNED FOR PRECISE ROOT MEAN SQUARE MEASUREMENTS

摘要

A method for precise root mean square (RMS) measurement of periodic signals based on signalreconstruction is analysed. The RMS value of a signal under test is determined in three steps. In the first step, the Fourier coefficients are estimated from integrative samples, in the second step the estimators are corrected, using the method of least squares with constraints and precision measurement of rectified signal average, and in the third step the RMS value is calculated from the Fourier coefficient estimators. Properties of integrative samples are analysed and the problem of choosing the optimal integration time is discussed. It is shown that this approach, optimal reconstruction with correction, considerably increases the accuracy of the RMS measurements of low frequency signals.