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This paper describes a system for generating and measuring extremely accurate phase angles that combines the digital synchronous signal generation with the synchronous subsampling technique, aided by digital phase regulation. The system can be set up with commercially available instrumentation. Experimental evidences suggest that the phase between two generated sine signals can be resolved to a few microradians up to the megahertz range. [ABSTRACT FROM AUTHOR]

This paper describes a five-terminal (four terminal with shield) digital impedance bridge aided by digital adaptive phase regulation. It allows the comparison of ac resistances and capacitances with outstanding accuracy and with measurement uncertainties bearing only some 10−6 Ω/Ω, as corroborated by extensive experimental investigations. [ABSTRACT FROM AUTHOR]

This paper describes three impedance bridges in operation at INMETRO: the two- and four-terminal-pair coaxial bridges and a digital quadrature bridge, including several comparisons among them in the nanofarad capacitance range. These comparisons have the objective to verify the performance and reliability of the coaxial bridges between themselves and to infer on the capabilities of a digital one, recently put in operation. The results obtained indicate that the more accurate coaxial systems are compatible with one another in the 10−7 level. The digital bridge is in agreement with the coaxial ones within a few parts in 106 or even less in some cases. [ABSTRACT FROM AUTHOR]

A method for estimating parameters of combined amplitude and phase modulation signals from digital sampling data is proposed. It can be employed with advantage to analyze combined modulation functions of commercial function generators. Though this problem of inference has applications in communication technology, it has also become a concern to the power industry in issues related to phasor measurement unit tests. Prior information available to metrologists about the signal components allows the reduction of the dimensionality of the search algorithm with consequent time savings. [ABSTRACT FROM PUBLISHER]

This paper describes a new calibration system developed at INMETRO to guarantee traceability of low-frequency alternating current (ac) voltage calibrations (<1 kHz) to a programmable Josephson ac waveform synthesizer. The automated full-synchronous system allows the synchronization of a commercial calibrator or signal synthesizer with a programmable Josephson voltage synthesizer system to be made by employing digital sampling and signal processing techniques, aided by adaptive digital control. It allows accurate determination of the spectral content of ac signals with minimum human intervention. System operation, measurement techniques, and data analysis are detailed. [ABSTRACT FROM PUBLISHER]

The measurement of the severity of electric light flicker is achieved using a complex model of the human response embodied in a flickermeter. The complex nature of the model leads to variations in flicker readings with voltage input that can be hard to predict. Uncertainty evaluation is therefore difficult to achieve by conventional methods, and a Monte Carlo approach is required. This paper describes the implementation of such an approach to evaluate the uncertainty for flicker measurements based on a model of the measurement. [ABSTRACT FROM AUTHOR]

This paper describes a sampling system designed using a commercial sigma-delta analog-to-digital converter (Σ-Δ ADC). In addition to characterization measurements using a conventional high-quality signal generator, a Josephson waveform synthesizer that provides ultimately noise- and drift-free voltages was used. To evaluate the suitability of this sampling system as part of a transfer power standard, additional comparisons of the root-mean-square (RMS) values measured were performed against a thermal converter and the primary power sampling standard at the Physikalisch-Technische Bundesanstalt, Braunschweig, Germany. Initial analysis of the measurement data shows an effective resolution in the range of 18-19 bits at an equivalent sampling rate of 64 kHz. The integral nonlinearity error of the system was measured to be within ±7 μV/V or one least significant bit at this resolution. [ABSTRACT FROM AUTHOR]

This paper describes the accurate methods for the determination of power quality parameters. The methods and procedures described apply to the measurement of harmonics, flicker, fluctuating harmonics, and interharmonics and allow uncertainties of some parts in 106 to be attained. [ABSTRACT FROM AUTHOR]

An easy-to-use and low-cost quasi-synchronous multichannel digital sampler controller to aid routine laboratory ac measurements by digital sampling is described. Using a single digital sampling voltmeter, accurate measurements of ac quantities can easily be done with uncertainties of a few microvolts per volt. Measurement results and consistent uncertainty calculations are described. [ABSTRACT FROM AUTHOR]

A recent upgrade of the primary standard for electric alternating power at the Physikalisch-Technische Bundesanstalt improved the measurements, indicating that standard uncertainties of the order of 1 μW/VA are attainable. Investigations done to ensure such low uncertainty figures are presented, and the evaluation of measurement uncertainties is discussed in detail. [ABSTRACT FROM AUTHOR]

Presents a study that evaluated the synchronous generation and sampling technique. Sources of errors; Estimation of uncertainties; Conclusion.