This paper describes a new four-terminal pair (4TP) digital sampling impedance bridge designed for the frequency range up to 1 MHz and small impedances, such as shunts. The bridge is capable of comparing impedance standards of arbitrary ratios in a full complex plane from approximately 100 k down to 50 m , limited by the maximum achievable current 3 A. To keep low uncertainties, a new multiplexer was designed and a very simple and fully automated linearity correction method based on the pair of calculable resistors was developed and validated. This paper describes the design and details of the bridge topology, basic uncertainty budget, and first results of the validation. The expanded uncertainty of impedance module is about 50 µ / at 1 MHz for impedance ratios up to 1:16 and voltage drops above 10 mV and the expanded uncertainty of a phase angle was about 360 µrad/MHz. Expanded uncertainty for frequency 100 kHz about 10 µ / was reached. Typical expanded uncertainty for low-impedance ratios below 1:1.1 is only 35 µ /. Set of measurement of impedance standards of known values and a small international comparison of ac-dc and phase angle errors of current shunts were carried out to validate the bridge capabilities in a wide range of impedances. The validation measurements showed the deviations of the bridge are below 35 µ / and below 350 µrad at 1 MHz.

No abstract

No abstract

No abstract

Uncertainty analysis of a very simple sampling phase meter based on four parameter sine wave fitting is presented in this paper. An uncertainty of a sample time and a measured voltage is assigned to every sampled point and a total uncertainty of a phase difference is calculated by means of the Monte Carlo method. Results show the total uncertainty is lower than 0.5 millidegree for selected digitizer. A noise of the measured signal or the digitizer is the largest contribution to the total uncertainty.Index Terms-measurement uncertainty, phase difference, Monte Carlo, sine wave fitting.