The authors propose to use the Virtual Standard® technology in conducting calibration operations for a wide range of measurements. The Virtual Standard® technology is a universal technology for determining and introducing corrections in measuring device readings to reduce their errors. Theoretical principles underlying the Virtual Standard® technology are discussed, and their operation flow chart and some experimental findings are provided.
The problems of metrological ensuring virtual measuring instruments (VMI) are discussed. The VMI classification is proposed. The principles of measuring instrument legalization are formulated as a base for the problem solving. As the basic problems, structural identification of VMI, and unauthorised access, and VMI calibration and standardization are pinpointed. It is shown that complete calibration is foreground for VMI similar as to usual measuring instruments, without necessity to certify, separately, measurement software.
This paper describes problems of measuring the noise figure when the noise figures are low and there is high mismatching of measurement system. Measurement errors can be identified using this method. Methods limiting the influence of a measurement system with real parameters are presented. The available accuracy in dependence on the parameters of the measurement system is described.
The paper presents the derived dependence on the total noise factor of cascade-connected linear two-ports in the conditions of energy mismatching. The method of assessing the uncertainty in measuring this factor, which takes into account propagation of standard partial uncertainties of the measurement of the set of four noise parameters, disposable power gains and input and output impedance of particular two-ports, is determined. The uncertainty analysis takes into account the correlation among these parameters. A strict dependence between the mismatching stages of two-ports in the cascade...
A traditional description of the measurement result obtained with the use of a definite measurement instrument is complemented by the information about its accuracy on the basis of technical specifications given by its producer or verified in checking and legalisation procedures. The paper presents the premises resulting from currently available technical possibilities, which show that it is purposeful to complement the set of functions realised in a microprocessor instrument with additional properties enabling the instrument user to access the information about the uncertainty of the...
This protocol was developed to estimate the uncertainty of measurement of a chemical analysis by utilizing in-house validation studies and quality control data. The approach was to generate an estimate of the uncertainty across the analytical concentracion range. This was to be expressed as a mathematical equation or factor that could be inserted into a Laboratory Information Management System (LIMS) and thus produce an uncertainty estimate from an entered analytical result. The aim is to identify as many sources of uncertainty as possible and account for them by appropriatte precision and...
In this paper we present results on load sensors based on the magnetostrictive delay technique. The sensors translate the displacement of soft magnetic plate, hard magnetic disk and aluminium disk into force with respect to three different magnetostrictive delay line set-ups. The range of displacement determines the range of measurable load. Stainless steel springs have been used as active core supports. The best results both in sensitivity and repeatability have been obtained using soft magnetic plate as active core.
Electronic systems for automated monitoring of the presence of dangerous gases are available nowadays in different configurations and with quite different capabilities. This work is presenting the development of an electronic instrument for monitoring the level of two gases (namely CO and CH 4 ) aiming for possible use in coalmines. The instrument is using SnO 2 sensors and is based on a graphical estimation of the concentration of each of the two gases realised by a combination of the information from the calibration curves of the two sensors. In this way, instead of trying to suppress the...
The current sensor presented in the paper is built around a relatively new category of materials expressed by magnetic amorphous wires. Its operating principle is based on the Matteucci effect occurring in amorphous wires showing high level of magnetostriction. The wire is wound around the conductor through which the current to be measured flows. Under certain conditions, at the ends of the wire sharp voltage pulses appear whose amplitude depends on the intensity of the circumferential magnetic field generated on the conductor surface and, implicitly, on the current intensity.
In this paper we present an overview of the electromagnetic field loop sensors measurement performances. The loop sensors are much utilised in electromagnetic field measurements (magnetic field measurement, simultaneous magnetic and electric field measurements). The knowledge of the influence of the dimensions sensor on measurement performances of the electromagnetic field is important both in sensor optimisation, and in the selection of the sensor for a certain application. The results of time domain measurements of the magnetic field near some appliances, made with an active magnetic field...