The goal of the paper is presentation of a new approach to the measurement of effective resolution (effective number of bits - ENOB) of the cyclic A/D converters (CADCs). The core idea of the approach is direct measurement of ENOB using, as a numerical measure, the number of true bits before the first erroneous bit (FEB) position. The position of FEB is determined as the first non-zero bit in the binary presentations of conversion errors. The definition of ENOB based on FEB is introduced and discussed. The particularities of the proposed method are analysed in simulation experiments. There are presented typical evolutions of FEB distributions in sequential cycles of conversion. Values of ENOB obtained using FEB-based method are compared with results obtained using the conventional approach to ENOB assessment. The comparison is performed on example of analysis of influence of DNL and INL errors of internal A/D converter on ENOB of CADC. The proposed method of the ENOB measurement gives more adequate information about the actual ADC resolution and weakens the influence of the form of testing signals on the results of the ENOB measurement.

In many circumstances software processing is the best and suitable way of improving image contrast, hence image quality. Different biomedical instrumentation and apparatuses encompass post processing units capable of optimal outcomes. However, in particular cases, especially for contour analysis, the above outcomes are not sufficient. Therefore, an alternative can be envisaged in designing image enhancer and intensifier to compensate image processing limitations. This aspect is very important regardless of computational costs of this alternative. This paper proposes some criteria of design image enhancer and intensifier for biomedical applications. Moreover, the hardware has been used for improving the quality of cardio-vascular image constrast with acceptable outcomes. The images come from different instrumentations, namely, diagnostic ultrasound and echocardiograph. In addition, a specific algorithm has been implemented by means of a variational approach based on Mumford & Shah functional to solve the magnification or zooming problem for a given digital image. The numerical solution of the system of elliptic PDEs associated with the MS functional can provide simultaneously noise suppression, extraction of shape and magnification of the image.

A new automatic system is described whereby precise, simple and reliable intercomparison of electronic voltage standards is enabled by using a self-developed 16 channel low-thermal switch and digital nanovoltmeter, controlled by the computer. It enables faster and easier comparison, as well as optimisation of the whole procedure. The control software was developed using a LabVIEW, and the obtained parameters are pointed out. At the Primary Electromagnetic Laboratory, which is a part of the Faculty of Electrical Engineering in Zagreb, the maintenance of the unit of volt is one of its important tasks, due to its role as a holder of national standards of voltage. Although the best possible accuracy (or maintenance of the highest level) is attainable by means of Josephson voltage standards, due to its costs and limited availability it is not the most practical, specially when the utmost level of accuracy is not essential. For measurement of voltage differences at a level of microvolts crucial attention has to be paid to avoid any unstable and changeable TEMS. Therefore, in the construction of the mentioned multi-channel low-thermal switch and digital nanovoltmeter this was the very important task.

We analyse the volt-amperometric (VI-) method for the characterization of minor loops of soft magnetic materials. By adopting several input signals and by operating at various frequencies in the 10 Hz – 10 kHz frequency range, we perform the measurement on a soft ferrite core. Through the use of two different measurement schemes, we control in the first case the voltage across– and in the second case the current through– the primary coil. Measurement results are reported and a comparison among the various techniques is provided throughout the paper. A commercial ferrite core and a Fe-Si thin lamination are used as our samples.

PDA-based instruments with wireless capabilities are a powerful aid to monitor and control applications. Using virtual instrumentation abilities of Labview 8.2, PDA, communications protocols and wireless devices we developed and tested some applications dedicated to the data transfer, workable for Pocket PC 2003. LabVIEW allow the addition of the dedicated module LabVIEW PDA Module, an essential resource in the development of graphical applications GUI usable on the PDA level