Frequency synchronization error correction by using DFT in sinusoidal voltage measurements

The paper presents a method of correcting a frequency synchronization error in the sinusoidal voltage measurement. Correction is performed by changing a frequency of the measured signal on the basis of the respectively determined synchronization error by using DFT. Carried out simulation experiments indicate that the correction can theoretically improve the accuracy of measurement of the RMS voltage to the level below 1 ppm. The results of measurements taken by a highly accurate voltmeter Agilent 3458 confirm the conclusions of the simulation, that it is possible to repeatedly reduce the frequency synchronization error by applying the developed correction method in the voltage measurement.