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 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 control the measurement. The new approach sets no special requirements on the input sawtooth impulse generator precision and the precision of the obtained differential non-linearity (DNL) characteristics mainly depends on the DAC used. Practical measurement results evaluated on data acquisition board Lab-PC-1200 with 12b ADC obtained by new method are compared with common static method results.

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 components designed to emulate the electronic measurement instrumentation. Such components are used to teach the learners how to create their own test benches. The correctness of the connection scheme, remotely set by the learners, is automatically verified, in real-time, by a specific module of the e-learning platform.

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 parametric method for functional testing can be carried out both manually and automatically.

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 described. The experimental results and the error analysis are also presented.