Entwurf nichtrekursiver Digitalfilter mit beliebigen Betrags- und Phasengängen

This paper presents an efficient multiple exchange algorithm for the frequency domain design of digital FIR filters with arbitrary magnitude and phase responses. The designed filters minimize theL ₂ norm of the weighted complex frequency domain error function subject to constraints on the resulting magnitude and phase errors. This general design criterion allows for an arbitrary trade-off between complexL ₂ approximation and Chebyshev approximation of given magnitude and phase responses. The optimization can be carried out by iteratively solving small quadratic programs. These linearly constrained subproblems can be solved using robust standard software.     

Magnetoresistive Sensoren

Depending on the angle between magnetization and current density in a thin permalloy film, the anisotropic magnetoresistive effect is utilized for high performance sensors. Both the parameters of the sputtering process and the sensor layout have to be optimized. Aiming a magnetic field resolution of some nT in a frequencey range from 0–1 kHz, the results of Wheatston-bridge circuits are discussed.     

Konvergenz der Kommunikationsnetze zu Multiservice-Netzen

The rapid progress in the convergence of communication networks (fixed and mobile networks with data networks) to multi service networks has an impact on the principles of the traditional switching technologies. Future requirements will also have to be fulfilled through service-convergence (bundling of individual services to new services) regardless of organizational or technical boundaries. Requirements in the information- and communication-business all the way to technical network aspects are to be faced. Based on developments in microelectronics, two converging evolutions by packet-oriented technologies (within the network and at the edge of the network) are now taking place. Starting with the principles of circuit-switching and packet-switching the change in today’s telecommunications world will be discussed. Apart from that emphasis will be put on the distribution of the switching functions within the network, the change of the network’s topology, as well as the influence on the signalling protocols (extensions and new approaches).     

Norm constraint regard for stable H2 controllers

For stable output controllers, the standard H₂ problem is modified by additionally including the H₂ controller norm.      

Die zweite Phase der Feldbusentwicklung

The past decade may be regarded as the phase of the fundamental developments in fieldbus systems that were based on the OSI model. Today we are entering a second stage. It is the objective of this issue to present the current state and where the further developments will lead to. This introductory article is intended to give an overview on the subject.     

Auswirkungen von Blitzschlägen auf 20-kV-Energiekabel

Recently appeared defects on high voltage cables have required an urgent evaluation of the impact of lightning strikes necessary. In some cases overvoltages between the copper wire screen of the cable and earth may appear which cause damages of the cablesheath. Field measurements with a classification of the voltage impulses at the copper wire screen have been made to evaluate the number of events. Additionally a numerical model was developed to study the effects of atmospheric discharges on underground cables with emphasis to the influence on the cablesheath. This numeric method was also applied to estimate the effectiveness of different protection arrangements. This contribution presents evaluation methods for overvoltages of cables and a model used firstly for calculating the stress caused by differential voltages and secondly to determinate the influence of protection measures.     

Messmethoden zur Charakterisierung von Mikrowellenleistungstransistoren

For first try designs of microwave power amplifiers it is necessary to know the entire physical behaviour of the used components with high accuracy. The attention should be directed especially to the center component of these circuits, the power transistor, whose nonlinear characteristics have an essential impact on the behavior of the whole amplifier. This article gives an overview of current methods of measurement for microwave power transistor characterization. Furthermore a measurement system is presented, capable of characterizing microwave power transistors within a frequency range from 30 kHz to 8.7 GHz at bias current up to 7.5 A including self heating effects.     

Special features of structural defects in undoped CdTe textured ingots produced by free growth from a gasdynamic vapor flow

The structural features of undoped CdTe ingots grown in a gasdynamic flow at 620°C were studied by selective etching and X-ray diffractometry. It is found that the samples grown at a deposition rate of up to 500 μm/h consist of independently growing rods with both [111] A and [111] B directions. This indicates that the vapor composition in the growth region is almost stoichiometric. Both rod types exhibited transverse striations due to rotation twins. The twin boundaries in rods with the growth direction [111] A were shown to be also small-angle boundaries with additional misorientation of separate twins of 0.2°–0.3°. __________ Translated from Fizika i Tekhnika Poluprovodnikov, Vol. 37, No. 2, 2003, pp. 129–133. Original Russian Text Copyright ? 2003 by Klevkov, Martovitskii, Medvedev.     

Koordinatenmesstechnik für biomedizinische Anwendungen

The importance of computer aided measurement techniques as a means of controlling industrial manufacturing and testing technical products with high accuracy is increasing ever more with the general goal of improving the quality of all kinds of products. This development started about twenty years ago and is still improving. There is also rapid development in biomedical technique and this demands the application of modern computerized measurement techniques and measuring devices. Especially computer aided co-ordinate metrology can be applied as a very important and universal tool for solving complex measuring tasks for workpiece metrology, to evaluate the measuring results to give the basis for the improvement and optimization of future work in the biomedical technique.     

Control system design based on holistic eigenvalue allocation

A trade-off between optimum allocation of the entire set of eigenvalues and the size of controller norm or a general actuator effort is carried out for continuous-time and discrete-time systems. Controllers achieving appropriate results are termed holistic. The design is based on the trace and determinant of the closed-loop state-space matrix. To solve the problem within the scope of actuating effort, the norm of the state controller matrixor the actuator effort transfer matrix are taken into consideration. The method is also extended for designing holistic observers. For preserving stability, a Lyapunov condition is included. An erratum to this article is available at .