The approach presented in the paper shows possibility of increasing performance of cyclic analog digital converters (CADC) [1]. In the paper, the intelligent version of CADC (ICADC) is considered. The main particularities is ICADC computes the binary codes of input signal samples using the model based on the adaptive algorithms developed in [2-5]. In the paper there are presented the results of real design and analysis of the laboratory prototype of sub-optimal ICADC.
Analog-to-digital converter additive post-correction using look-up-tables is considered. In a practical post-correction system, the correction values must be stored using limited (fixed-point) precision. In this paper the effects of limited precision in the correction values is investigated. A theory for approximating the SINAD after correction using fixed-point values is presented. The theory shows good agreement when compared with simulation results.
This paper describes the system under construction at I.N.Ri.M. for the characterization of high resolution DACs and ADCs. The main measurement instrument used as a reference is a high precision sampling multimeter, which is properly configured for the measurement of both dc and ac voltages supplied by the DAC under test. A proper voltage pattern is supplied to the ADC under test by means of a multichannel output board put inside a computer, combined by suitable supplementary electronic circuits. The constructed signal is then measured by the multimeter and analyzed by the computer.
This paper presents a new approach to static parameters testing of analog-to-digital converters (ADCs). In comparison to ordinary approaches, the measured transition levels are not related to zero potential but to the transition levels of a reference ADC, which is of the same type as a tested ADC. These differences, which can be in the extreme case in the range of a few least significant bits (LSB) of the tested ADC, were measured by a succesive approximation principle-based test system, with a digital-to-analog converter (DAC) in the feedback. A special algorithm has been proposed to...
The study branch concerning computer science and engineering (which offers the study programs of a number of Faculties of Electrical Engineering and Informatics) is often primarily focused on software engineering. It brings a tendency to minimize an amount of basic courses relevant to electrical engineering in this study branch. It concerns also the education in measurement and instrumentation. The paper describes the approach applied at the CTU in Prague, Faculty of Electrical Engineering to solve this matter. A content of lectures and labs of the basic course “Measurement in Digital...
The paper presents a remotely accessible laboratory for real-time electric and electronic measurement experiments, distributed on geographical scale and accessible to users through common Web browsers. The remote laboratory is part of an innovative platform for distance learning including a traditional Learning Management System and innovative modules enabling the learners to control real instrumentation. The paper describes the platform structure and its innovative functionalities in comparison with classical web-based training systems focusing, in particular, on a set of hardware...
In this work a data acquisition board (DAQB) with data transfer by parallel port LPT and the associated virtual library included into LabVIEW software are presented. The DAQB developed around a National Semiconductor LM 12458 device, have the capability to perform tasks that diminish the host processor work and is capable to communicate with the host computer by using a set of drivers associated. Highly integrated device circuit that has into it the most components of the board, facility in data handling, good metrological performance and a very low cost are the benefits of the proposed...
The article presents the parametric method for functional testing of virtual instruments. Presented method allows to define the quality of project implementation of virtual instruments. Owning to the definition of weight matrices of user selections, for particular elements of the user interface in virtual instruments, already on the stage of their design, it is possible to estimate the risk related to their implementation. The presented parametric method for functional testing allows to define mutations, which result from incorrect design implementation of virtual instruments. Tests by...
The paper presents an approach to Real-Time virtual instrument design. It uses cyclical buffer technique to obtain an instrument working in Real-Time mode using general purpose operating system and basic data acquisition card. Advantages and drawbacks of the approach in comparison to hardware Real-Time solutions are presented. Software architecture of the cyclical buffer solution is discussed in detail. Dependency between the cyclical buffer fill ratio and convergence function is presented. Experiments conducted in order to determine abilities of the cyclical buffer are described. Three main...
The paper presents a virtual instrument based on a quasi-balanced bridge designed to measure the parameters of an inductor, a capacitor or a resistor. The unknown element, in series with a reference resistor, forms the real half of an ac bridge, while the software model of a resistive potentiometer shapes the virtual half. Actually, one acquires the supplying voltage and the voltage across the reference resistor respectively, after which these signals are digitally processed according to the quasi-balanced bridge algorithm. Both the hardware and the software of the prototype model are...