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This article presents results of a comparison of a traveling ac voltage standard, which was a fused-silica planar multijunction thin-film thermal converter (PMJTC) developed at the National Institute of Standards and Technology (NIST). The ac–dc voltage-transfer difference of the standard was measured at 2 V and selected frequencies from 1–30 MHz against primary thermal ac voltage standards at the Silesian University of Technology, Istituto Nazionale di Ricerca Metrologica, RISE Research Institutes of Sweden, and Trescal A/S Silkeborg.

This paper presents the results of determination of the ac–dc voltage transfer difference of two calculable thermal ac voltage standards, developed at the Silesian University of Technology, Gliwice, Poland, in 1–30 MHz frequency range. Two experimental methods confirmed with high accuracy the results obtained from the mathematical model.

The article presents construction, mathematical model and calibration results of a 50 mA coaxial current shunt developed at Silesian University of Technology (SUT) in Gliwice, Poland.

The article presents results of measurements of errors of electronic energy meters measuring energy consumed by LED lighting used in households.

This paper presents results of a trilateral comparison with a traveling ac voltage standard comprising a planar thin-film thermal converter. The ac–dc voltage transfer difference of the standard was measured at 1 V and at selected frequencies from 20 Hz to 1 MHz against primary thermal ac voltage standards at the Silesian University of Technology, Istituto Nazionale di Ricerca Metrologica, and Trescal.

This paper describes two calculable thermal ac voltage standards developed at the Silesian University of Technology in Gliwice, Poland. The design and mathematical model of these standards made calculation of their ac–dc transfer differences with very low uncertainty possible, comparable to the uncertainty of the best available calculable ac voltage standards in the 10 kHz–1 MHz frequency range. The correctness of the results of the ac–dc transfer difference calculation was also confirmed experimentally.

The paper describes the design and mathematical model of a 50 mA coaxial current shunt developed at Silesian University of Technology (SUT) in Gliwice, Poland. The AC-DC transfer difference of the shunt transimpedance and its phase displacement were calculated based on the mathematical model of the shunt. The results of AC-DC transfer difference calculation were validated by calibration of the shunt at Swedish National Metrology Institute RiSE.

The paper presents results of determination of the AC-DC voltage transfer differences in 1 MHz - 30 MHz frequency range of the two reference thermal voltage converters developed at Silesian University of Technology (SUT). Two experimental methods confirmed high accuracy of results obtained from the mathematical model.

The paper presents results of a trilateral comparison of a travelling AC voltage standard, which was a fused-silica NIST planar multijunction thin-film thermal converter. The AC-DC voltage transfer difference of the standard was measured at 2 V and selected frequencies from 1 MHz to 30 MHz against primary thermal AC voltage standards at SUT, RISE and Trescal.

Results of investigations of selected highly stable wideband AC sources to be used in AC-DC transfer systems in the frequency range from 1 MHz to 10 MHz are presented in the paper. The most stable sources were pointed out and tested. Moreover, impact of the RF amplifier on the stability of the generated AC voltage was checked and discussed. Finally AC-DC transfer difference measurements were performed with and without an RF amplifier to prove its usefulness in the high-frequency AC-DC transfer.

This paper presents an analysis of the effect of the digital-to-analog converter resolution on the root-mean-square value of the sinusoidal signal generated by the digitally synthesized source (DSS) of low-frequency standard ac voltage. The analysis applies to the DSS being calibrated using the peak-to-peak method.

This paper presents methods of calibration of digital sources of ac voltage of very low frequency (0.001–100 Hz) and of effective value from 0.5 to 5 V. This work deals primarily with the calibration methods of the digital source of the sinusoidal signal [digitally synthesized source (DSS)] which is approximated with the staircase waveform. The construction of the DSS and the calibration system is presented. The calibration methods are divided into dynamic and static. Of the dynamic methods, the thermal method and integrating sampling method are briefly presented. Of the static methods, the step and the peak-to-peak methods of calibration are briefly presented. The potential applications, basic features, and accuracy of all four methods are discussed. This paper also presents a comparison of results obtained using the methods of calibration described in this paper.

Despite wide availability of AC voltage calibrators, digitally synthesized sources (DSS) in the form of function/arbitrary waveform generators (AWG) and radio-frequency (RF) generators there is still deficiency of AC voltage sources of sinusoidal voltage, able to synthesize signals from approximately 10 Hz up to hundreds of MHz with very high short-term stability of the amplitude and whose amplitude, in the order of a few volts, could be adjusted with high resolution, down to 10−6 V/V or better. Adding the second channel could further increase the versatility and applications of the source. In this case the phase difference between sinusoidal voltages, generated by the source, should be adjustable with the resolution in the order of 10−6 radian. Such a source could be used in numerous metrology and diagnostic applications like primary standards of AC power and energy, voltage and current (AC-DC transfer systems), fully digital or digitally-assisted impedance bridges, insulation diagnostics systems and many others. Our paper will present a review and comparison of existing sources, results of their investigation, formulation of requirements and preliminary proposals of the design of the new source.

This paper describes two calculable thermal AC voltage standards developed at the Silesian University of Technology (SUT) in Gliwice, Poland. The design and mathematical model of these standards made possible calculation of their AC-DC transfer differences with very low uncertainty, comparable to the uncertainty of the best available calculable AC voltage standards in 10 kHz–1 MHz frequency range. The correctness of results of the AC-DC transfer difference calculation was also confirmed experimentally.

The paper present results of trilateral comparison of a travelling AC voltage standard with PTB/IPHT planar thin-film thermal converter. The AC-DC voltage transfer difference of the standard was measured at 1 V and selected frequencies from 20 Hz to 1 MHz against primary thermal AC voltage standards at SUT, INRIM and Trescal.

New planar multijunction thermal converters (PMJTCs) with low-power coefficient and high dynamic range using CuNi44/BiSbTe thermocouples have been manufactured. In series connection with carefully evaluated range resistors for voltages up to 1000 V they result in AC-DC voltage transfer standards with known AC-DC voltage transfer difference at low frequencies, for which the voltage step-up procedure is not necessary any more.

The design of a new planar or thin-film multijunction thermal converter (PMJTC) on a quartz membrane and a quartz crystal chip results in a calculable standard for AC-DC voltage transfer for frequencies from 100 kHz to 100 MHz with improved uncertainties. This is due to smaller dielectric losses and higher insulation resistance in the quartz membrane and the quartz chip. The window with the membrane is anisotropically etched into the quartz crystal chip. For the first measurements, the temperature of the heater was radiometrically sensed with a thin-film infrared sensor and later with an array of 100 Cu-CuNi thermocouples. At frequencies higher than 100 kHz, the AC-DC voltage transfer differences are one order smaller than with the standard PMJTC with the Si/sub 3/N/sub 4//SiO/sub 2//Si/sub 3/N/sub 4/ sandwich membrane on a silicon chip.

This paper describes the realization of a two-terminal-pair digital impedance bridge and the test measurements performed with it. The bridge, with a very simple architecture, is based on a commercial two-channel digital signal synthesizer and a synchronous detector. The bridge can perform comparisons between the impedances having arbitrary phase and magnitude ratio. The bridge balance is achieved automatically in less than 1 min. $R$ – $C$ comparisons with calibrated standards, at kilohertz frequencies and 100- $\text{k}\Omega $ magnitude level, give ratio errors of the order of $10^{-6}$ , with potential for further improvements.

This paper is focused on the ambient temperature coefficient of the output frequency of thermal piezoacoustic sensors operating in a twin configuration (differential mode). The sources of the ambient temperature coefficient of the sensor are pointed out and the partial temperature coefficients of each block of the measurement chain are analysed with special attention to the influence of the non-linearity and mismatch of the frequency-temperature characteristics of the active and reference sensor. The derived equations are verified experimentally using the model of a thermal r.m.s. converter. A method for the reduction of the ambient temperature coefficient based on the proper choice of resonance frequency of the reference sensor is proposed. The presented analysis is valid for small variations of the ambient temperature, within the range of a few degrees Kelvin.

The low-frequency AC-DC voltage transfer differences of thermal converters for higher voltages with planar multijunction thermal converters (PMJTCs) and series resistors have been determined by using only the assumption of a linear change of the low-frequency AC-DC current transfer difference of the PMJTC with input power. Uncertainties of less than 1 /spl mu/V/V are achieved up to 1000 V.

The “Automated impedance metrology extending the quantum toolbox for electricity” project (AIM QuTE) will extend Josephson impedance bridges capabilities to the whole complex plane with the best level of uncertainties (0.05 ppm). In parallel, fully digital bridges will be developed to reduce the operator workload imposed on national metrology institutes for the realisation of the impedances scales and for calibrations. The target level of uncertainty for these fully digital bridges is parts in 10 −7 . Furthermore, sub-pF standards will be developed to establish traceability of very small capacitances. An electronic impedance simulator, which will cover a very large region of the complex impedance plane, will also be realised, it will significantly reduce the number of standards required to link traceability of top level calibration laboratories to national metrology institutes.

The paper describes a high-performance digitally synthesized source (DSS) designed for low-frequency AC voltage calibrator. The source generates very stable and accurate sinusoidal AC voltage from 1.2 to 12 V in frequency range from a few muHz to 100 kHz.

New Planar Multijunction Thermal Converters (PMJTC) with low power coefficient and high dynamic range using CuNi44/BiSbTe-thermocouples were developed. Together with carefully evaluated range resistors for voltages up to 1000 V they resulted in ac-dc transfer standards with negligible ac-dc voltage transfer difference at low frequencies. The measuring system was improved with a new highly stable low frequency voltage source.

Three methods for the determination of the RMS value of AC voltage at low frequencies are compared: the step calibration of a digitally synthesized source, the optimized sampling method, and the AC-DC voltage transfer with a multifunction thermal converter. The three methods agree within 1/spl times/10/sup -6/ with an uncertainty of 2.5/spl times/10/sup -6/ in the frequency range from 10 Hz to 100 Hz.

The design of a new planar or thin-film multijunction thermal converter (PMJTC) on a quartz chip results in improved performance for frequencies higher than 100 kHz due to smaller dielectric losses and higher insulation resistance in the quartz membrane and the quartz chip. The window with the membrane is anisotropically etched into the quartz crystal chip. The temperature of the heater is radiometrically sensed with a thin-film infrared sensor. At frequencies higher than 100 kHz the ac-dc voltage transfer differences are one order smaller than with the standard PMJTC with the Si/sub 3/N/sub 4//SiO/sub 2//Si/sub 3/N/sub 4/ sandwich membrane on a silicon chip.