True RMS voltmeter calibration by reference square waveform signal and algorithm for measurement and processing of results

An approach for calibrating of the AC voltage of True RMS voltmeters is proposed, using reference square waveform signals instead of the traditionally used harmonic (sinusoidal) signal. A computer-based automation system and an algorithm for calibration of True RMS voltmeters have been implemented.The algorithm performs the sequence of operations for control of the reference calibrator Metrix CX1651 and the calibrated True RMS voltmeter PICOTEST M3500A, setting reference voltage values from the calibrator, performing multiple measurements at the calibration point, extracting measured results and extracting the measured results to obtain an estimate of the actual value of the measured voltage values and an estimate of the extended uncertainty at the calibration point. Based on the results of calibrations, the two approaches were analyzed and compared, which proved their equivalence.