We propose a method to determine the reference impedance of the TRA calibration technique for vector network analysers. This method was developed within the framework of our activity on traceability of on-wafer S parameters measurements. Starting from a modified TRA calibration procedure, we demonstrate the possibility to determine the calibration reference impedance, and leading to a significant reduction of the measurement uncertainties. In comparison with results obtained using the reference multiline TRL calibration technique, the results that we obtain show the efficiency of the present method.

The LNE has recently developed a 1 V programmable Josephson voltage standard specially dedicated to its transfer activities such as calibration of DC voltage references (Zener diode reference and Weston saturated standard cells) and digital voltmeters of high precision. This new programmable Josephson voltage standard allows the LNE to propose new calibration capabilities with reduced uncertainties while taking advantage of the simplicity to operate programmable Josephson array. The 1.018 V output voltage of the Zener diode reference can then be calibrated with a typical relative uncertainty of 80 nV (k = 2) in the framework of routine calibration services (an improvement by a factor 7). This paper describes the design of the new system and its metrological performances.

This paper describes a new primary standard at LNE for precision measurement of RMS values and total harmonic distortion of periodic signals containing a fundamental frequency at 50 Hz and quasistationary harmonics which maximum order is 50. The method is based on the sampling of the signals and the analysis of the samples by discrete Fourier transform. The traceability to the SI units is ensured by comparing the measurements to those obtained using a thermal converter. The standard uncertainty for RMS value and total harmonic distortion are respectively 22 µV/V and 0,0025% for all the signals studied.

The article presents the new electrical power measurement capabilities at LNE. The primary standard is based on sampling techniques. The power is calculated with a discrete Fourier transform algorithm, which is used to process the quantised samples of the voltage and current signals. Up to now, this primary standard was characterised only to measure active power for sinusoidal signals in the 45 Hz–65 Hz frequency range. From now on, the reactive power can also be measured and the frequency range has been extended to 400 Hz.

The RMS value of a signal is measured by averaging its squared value over an infinite duration, and similarly a power is measured by averaging the product of two signals (voltage and current). These computations of square, product and average are very easy when the signal has been digitised, but this digitisation carries three distinct sources of errors: truncation, sampling and quantification. These three error sources are studied independently of each others, as well as methods for reducing them, especially the use of a weighting window. With this “windowing”, a statistical study of the simultaneous effect of these three error sources has been made by simulation with a very large number of parameters values, and formulas are presented, which link the standard deviation to the resolution and the number of samples.

This work explores MEMS (Micro-ElectroMechanical Systems) potentialities to produce flexible AC voltage references through mechanical-electrical transduction that could be used for high precision electrical metrology and for applications in miniaturized instrumentation. AC voltage references ranging from 2 V to 90 V have been designed and fabricated using the same Epitaxial Silicon On Insulator (SOI) Surface Micromachining process that permits an accurate control of both dimensions and material properties. The measured MEMS AC voltage reference values have been found in a good agreement with the calculations performed with Coventor software. These test structures have been used to develop the read-out electronics to drive the MEMS and to design a second set of devices with improved characteristics. Deep Level Transient Spectroscopy measurements carried out on the new MEMS showed resonance frequencies of about a few kilohertz, which makes it possible to have AC voltage references working from about tens of kHz. Moreover, the stability of the MEMS out-put voltage at 100 kHz has been found very promising for the best samples where the relative deviation from the mean value over almost 12 h showed a standard deviation of 6.3 × 10^-6, which is a very good result.

We present our experimental set-up and discuss the results obtained within the framework of the ANR-TRIMET project which aim was the closure of the quantum metrological triangle (QMT) at a relative uncertainty level of 1 part in 10⁶. This experiment consists in achieving Ohm’s law with the three effects used and investigated in quantum electrical metrology: Josephson effect (JE), quantum Hall effect (QHE) and single electron tunnelling effect (SET). The aim is to check the consistency of the phenomenological constants K_J, R_K and Q_X associated with these effects and theoretically expressed with the fundamental constants e and h (elementary charge and Planck constant, respectively). Such an experiment is a contribution for a new definition of the International System of Units (SI). Also, the obtained results are a first step towards a determination of e.

To fill the gap of intermediate frequencies 100 kHz–100 MHz for which still remains a lack of traceability of impedance measurements for recent measurement instruments, LNE has established the traceability of a 4 ports vector network analyzer (VNA) and applied the method of Suzuki to measure four terminal pair impedances (Z4TP). In order to establish the traceability of the 4 ports VNA, used to measure Z4TP, LNE has investigated successively two different ways. We have developed 4TP calculable thin-film resistors, and then we have established the traceability of the “Unknown Thru” calibration method. We will show the two approaches and the measurement results up to 10 MHz obtained for a 1 000 pF capacitor with the associated uncertainties.

This paper describes the development of a new power standard based on a commercial thermocouple sensor. A calibration with a twin microcalorimeter has been performed in order to determine the effective efficiency of the sensor. A calibration using thermal transfer allows us to validate the results got with the microcalorimeter. LNE has got a new power standard for low frequencies.

Two compensated current comparators with magnetic flux cancelling have been made in the 1970s by the LCIE (Laboratoire Central des Industries Electriques) as a reference for high current transformers calibration for currents up to 50 kA at industrial frequencies 50 Hz, 60 Hz and 400 Hz. They are associated with manually operated electronic equipments: an adjustable phantom burden and a ratio error set capable to provide with high accuracy the quadrature and the in-phase components of the current transformer errors. This article presents the work that has been done to entirely redefine theses devices by abandoning the idea of a direct servo system of the old equipment and replacing it by a software servo that offers high calibration stability, better incertainties and fully controllable by a remote computer via an USB connection, allowing full automation of the procedure.