Development and implementation of series of precision wideband system oriented AC voltage multimeter
AC voltage measurement is the most common problem in electrical quantities measurement. The AC multimeters performance analysis shows that high accuracy is achieved in a narrow band of frequencies while there is a need to improve the accuracy not only in the sound but also in the short and in the ultrasonic frequency range. Therefore, element wise additive and multiplicative error correction technique to improve the accuracy was proposed. For this purpose, measurement channel is divided into functional blocks, each of which is complemented by a feedback circuit and aback up system. Measurements are carried out in the following way: the first input signal is converted by the main and backup systems together with upstream blocks of the main system. Backup systems with upstream blocks of the main system must have the same transformation ratio as the main system. Then the measured quantity is transformed by blocks of the backup systems with upstream blocks of the main system with chain connection of feedback circuit of each unit of the main system. The result is valued as a difference when using the element wise additive correction algorithm, and as apart of the above results when using the element wise multiplicative correction algorithm. The additive correction is more effective with small multiplicative errors. In the project the combination of two techniques is proposed in order to extend the frequency range by an order. The new approximating weight window was proposed for digital processing samples of instantaneous values for integral signal characteristics such as average, root-mean-square value, signal power, spectral components. The developed methodology and practical implementation.