To calibrate power and power quality measurement instruments such as flicker meters or harmonic measurement devices, several alternative techniques are generally used or proposed: • Using a reference device to make measurements which can be compared against those made by the UUT. • Applying variable loads to a static, impedance loaded power line to induce required conditions. • Generating the required signals with a precision signal source. This paper discusses the third option. There are a number of benefits to this approach, as well as a number of difficulties to overcome and decisions to...
Principles of complex software and hardware design of the sub-optimal low-energy cyclic ADC (CADC) are presented. The extended conversion algorithm for estimates computing is discussed. Upper boundaries of CADC resolution, rate of conversion and the ways they can be achieved are analyzed. Properties and general advantage of sub-optimal CADC are discussed and investigated in simulation experiments.
Test and self-diagnosis are important for the reliability of embedded measurement systems. For such mixed-signal systems it was introduced any special methods of design-for-testability. This paper will discuss any problems of possible structures by using the analogue Boundary-Scan method and its implementation.
The progress in the technology of the analogue to digital converters (ADCs) suppresses the error effects linked with its inherent architecture. Multiperiodicity of differential nonlinearity and the impact of analog components at the ADC input on the integral nonlinearity prefers unified behavioural error model expressed as one dimensional image in the code k domain. The paper presents two new methods for low code frequency testing. The first one is based on synchronous detection of higher harmonics in ADC output record. Second apply repetitive best fitting method to estimate the harmonics....
It is dispensable to develop the discriminating method of the human body tissues for the automation of the operation using robots. The piezoelectric elements are used as the sensor to measure the qualities of the living body. The discrimination for various meats as the living body is tried using the developed tactile sensor. It is shown that the discrimination among the living tissues is possible using the proposed tactile sensor.
In this paper we present a new sensor able to detect absolute and incremental angular position, having a simple construction. The sensing technique is based on the magnetostrictive delay line principle. The dependence of the sensor on the sensing core rotation was measured and filtered. Thus, a sinusoidal response with an uncertainty of 0.05% was realised. We also demonstrate the ability of this principle idea to be used as a dynamic displacement sensor in the range of 15 mm.
The paper describes the realization of a measurement system for executing Eddy Current Non Destructive Testing (EC-NDT) to detect defects on conductive materials. The measurement method is based on the adoption of a useful parameter, the mutual impedance matrix, obtained using a suitable probe and analyzed by means of a novel low cost non-iterative inversion algorithm. In particular, the probe is constituted by a set of coils arranged in a two-dimensional array: during a measurement session, the mutual impedance matrix is obtained exciting one coil at time and capturing the voltage at the...
The main purpose of this paper is to present some metrological aspects of identification and grouping of harmonics and interharmonics and calculation of total harmonic. The Virtual Instrument for identification of distorted signal spectrum is described and the demonstration may take place at the presentation of the paper at the oral or poster session. We define the total harmonic and interharmonic distortion coefficient and analyse its sensitivity to variation in fundamental and interharmonic frequency and sensitivity to incompleteness of samples for five different cases: rectangular window,...
The quality of an evaluation of dynamic parameters of ADCs and AD modules is strongly dependent on the quality of testing signal generator. The most important parameters are the signal to noise ratio (SNR) and the spectral purity (THD). Besides, the short-time frequency and amplitude stability are also necessary to be considered, but it is often marginalized. However, they also influence the accuracy of the further evaluation. A possibility, how to estimate this imperfection, is presented in the paper.
Only complete expression of measurement result (measurement uncertainty included) makes possible correct interpretation of measurement results and reliable decision-making. Estimation of measurement uncertainty is complex and time consuming for some stand-alone digital instruments, and especially for indirect measurements results. It is possible to integrate calculation of measurement uncertainty into digital instrument containing processor. For direct and indirect measurements it is advantageous to develop appropriate software application for integration of digital instrument(s) and...