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This article presents a comparison of measurement methods for current and voltage distortions in low-voltage networks in the frequency range from 2 to 150 kHz (supraharmonics). The comparison encompasses the methods informatively described in IEC and CISPR international standards, as well as other innovative techniques presented in the literature. This work is carried out within a novel framework that includes advanced and complex synthetic test signals, as well as real grid recordings that allow an accurate comparison of the performance of the tested methods. Specifically designed indices are employed to characterize the accuracy of the tested methods in the frequency and amplitude assessments. In light of that, the strengths and weaknesses of the methods are identified. The results of this article contribute to the ongoing standardization work carried out by the IEC SC77A/WG9 with the purpose of defining a normative measurement method suitable for assessing grid disturbance levels in the range from 2 to 150 kHz. [ABSTRACT FROM AUTHOR]

This article proposes an online scheme for state estimation of a generic class of nonlinear dynamical systems in the presence of abnormal measurement data from sensors. We thoroughly illustrate why the performance of standard recursive Bayesian inference degrades in the presence of any measurement distortion. After demonstrating how different abnormalities can be accommodated explicitly inside a generic state–space model, we propose a robust mechanism to perform recursive Bayesian inference on the presented model to not only detect but also mitigate the effect of corrupted measurements in the final state estimates. Using simulations and experimentation, we demonstrate the success of the proposed framework in reducing the impact of different types of distortions in measurements. The ability to tackle different kinds of measurement abnormalities during online inference sets the proposed method apart from the existing techniques. [ABSTRACT FROM AUTHOR]

The transient response of electrocardiogram (ECG) amplifiers is investigated in the light of the IEC 60601 performance standard for electrocardiographs. Simulations and bench tests carried out on models of several electrodes reveal that the undershoot limit of $100~\mu \text{V}$ and the recovery slope limit of 300 $\mu $ Vs−1 in response to a narrow 3-mV, 100-ms rectangular pulse are violated when the recommended input impedance of 10 $\text{M}\Omega $ is used in the amplifier. Analyses of dc and ac coupling of the electrodes to the amplifier are carried out, and the constraints are established for the amplifier input impedance based on the electrical properties of the electrodes. We recommend that the amplifier input resistance needs to be determined as $\text{R}_{\mathrm {in}} >60\text{R}_{P}$ or $>25/{\text{C}}_{P}$ , whichever is greater, where ${\text{R}}_{P}$ and $\text{C}_{P}$ are the resistance and capacitance of a simple electrical model of the electrode. In the case of ac coupling of the electrode to the amplifier, $\text{C}_{C}\text{R}_{\mathrm {in}} > 6$ s, where ${\text{C}}_{C}$ is the coupling capacitor. The results of simulations and tests suggest that an amplifier input impedance exceeding 3 $\text{G}\Omega $ and a cutoff frequency no higher than 0.05 Hz are necessary in order to meet the IEC 60601 performance criteria and avoid distortion of the recorded ECG signal. [ABSTRACT FROM AUTHOR]

When a polarized polychromatic beam passes through a quarter-wave retarder, the constituent spectral components suffer different changes in the state of polarization. As a result, when the beam passes through an analyzer, the intensity of the resultant beam changes, depending on the orientation of the analyzer, state of polarization of the input beam, spectral and spatial intensity distribution of the source and the wavelength. dependent retardance of the quarter-wave retarder. The intensity variation of the resulting beam is theoretically and experimentally observed, with the variation of the azimuthal angle of the analyzer for film-type chromatic and prism-type achromatic quarter-wave retarders. The spectral performances of achromatic retarders are generally evaluated by measuring, retardances at discrete wavelengths by using a monochromatic beam of light over the wavelength range of interest. In this study, a simple method is used for computing the fractional nonlinear polarization (FNLP) from theoretically and experimentally obtained intensity variations for evaluating the spectral performance of both achromatic and chromatic quarter-wave retarders operating over a broad spectral range in the visible region using a polychromatic beam of light. FNLP variation is also shown for a film-type chromatic quarter-wave retarder using a monochromatic source of light. The experimentally obtained values are compared with theoretical values and a good agreement is observed. The applications of the method for the performance evaluation of quarter- wave retarders are discussed. [ABSTRACT FROM AUTHOR]

This paper describes the significant enhancements brought to an original methodology designed for testing measurement software. In a previous paper, the authors proposed a black- box seven-step procedure that allows the functional verification of complex instrument software to be performed. The main features of the procedure are concerned with the following: 1) the ability of reproducing actual correlations among the software inputs and 2) the need for a limited number of test cases. Making use of innovative statistical techniques, the methodology performance and reliability have been enhanced. Two further steps have been added with the aim of improving the correlation coefficient assessments and providing the estimations with a confidence level. Finally, a new strategy has been studied to optimize the number of test cases. The effects of the new solutions on the performance of the methodology are evaluated by applying the procedure to a complex software module employed in an automotive system. A comparison with the previous methodology version is also reported. [ABSTRACT FROM AUTHOR]