9762 papers found
This paper presents the model of closed loop Hall effect current transducers. The model complies with the physical proprieties of the real system and it is useful for the analysis of the transducer’s work with deformed input signal.
The analog to digital front ends of measuring instruments affect crucially the interpretation of the signals acquired from the real world into the digital domain and their back presentation. The signal processing in the digital domain due to its stability meets usually the requirements on the uncertainty of the measuring instruments easily. ADCs and DACs influence dominantly the accuracy of instruments and limit the signal dynamic and their applicability. The exact error description and standardised testing methods are required by the end user. Moreover, the simplification of the error...
The aim of this paper is to provide the basis for the calibration of a hydrophone "in situ", thus assigning a value of uncertainty, which may be high, but according to requirements may be sufficient.
Operation and effectiveness of most electronic systems is strongly affected by their noise rejection capability. The performance they exhibit in the presence of noise is therefore assessed since the early production stage, as well as routinely during periodical maintenance actions. To carry out appropriate tests suitable noise sources are needed. Actually, only white noise sources are widely available on the market; generators capable of producing colored noise are instead very unusual. In theory, ordinary arbitrary waveform generators could be used, once suitably programmed to serve as...
This paper shows that the increasing complexity of new equipment for the power grid, mainly transmitted through processes of additional software, is an important issue and needs to be quickly assimilated by the metrological controls to prevent the emergence of problems in the way of smart grid. This paper aims to describe all relevant aspects of this particular experience revealed in Brazil, discussing the real scenario and its challenges opposites.
The paper deals with the definition of dynamic performance of Analog-to-Information Converters (AICs). These components allow of overcoming the sampling frequency limits of the Shannon's theorem, by assuming that the observed signal has a sparse representation in a given domain. The paper aims to verify the behavior of standard parameters currently defined for Analog-to-Digital Converters when applied to the AICs. To this aim, several simulations and experimental tests have been carried out to study the influence, in the frequency domain, of quantization noise and nonlinearity on the AIC...
A measurement system for the correction of gradient-field measurements using stretched wires is described. Relative field multipoles of a magnet are measured through the oscillating-wire technique. Then, by means of the same setup, the multipoles are used to correct the gradient measurements with the stretched wire technique. In this paper, after an analytical background on stretched and oscillating wire methods, the proposed correction is described. Results of experimental validation of the proposed correction on measurements of a quadrupole for the CLIC accelerator study at CERN in the...
This paper describes the calibration of pH sensor located at the OBSEA marine observatory. This instrument is based on an industrial pH electrode that is connected to a CTD instrument (Conductivity, Temperature, and Depth). The calibration of the pH sensor has been done using a high precision spectrophotometer pH meter from Institute of Marine Sciences (ICM), and in this way it has been obtained a numerical function for the pH sensor proportional to real pH.
A smart current control system for enhancing performance of a superconducting cable test station is proposed. According to the Fuzzy Gain Scheduling logic, the controller parameters are modulated by the working conditions. An improved flexibility for the definition of the set point is achieved. The system effectiveness has been proved through several simulations and demonstrated experimentally on the Facility for Research on Superconducting Cables at European Organization for Nuclear Research (CERN).
The paper deals with measurement and control aspects of active power filtering in ship systems. A main focus of the paper will be concentrated on the analysis of the ways of improvement of compensating current generation algorithms. Two aspects of improvement will be discussed: a choice of an appropriate algorithm and an assessment of the quality of compensation by analysis of resulting waveform distortions on power supply side.