bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation of 3G radio network topologies considering performance and exposure aspects
Authors: Buddendick H. , Wertz P. , Eibert T. F. , Landstorfer F. M. , Wölfle G.
Published: April 2010

Abstract. Five different radio network topologies, in the following referred to as "scenario", have been analyzed with regard to their capability to cover a medium size city with 3G mobile services. T-Mobile launched this study to assess different radio network topologies in terms of exposure. Thus, the main focus is to examine if, for exposure reasons, a medium size city can be covered with outer-city located sites. The radio network topologies discussed in this paper can generally be divided into two categories: In category one, the sites are located in the city, and in the other, the sites are located outside of the built-up area. In both cases the number of sites per scenario varies, and additionally the antenna height and site distance to the built-up area vary for the second category. The investigations are performed with a ray optical propagation model based on 3-D building data and a dynamic 3G network simulator. A mix of four services and a realistic spatial traffic distribution based on land usage is assumed. The performance of the scenarios, assessed by the evaluation of coverage and capacity, is examined together with the exposure. It is shown that network topologies with sites located only outside the city are not an adequate solution due to capacity constraints and coverage problems with high data services. A promising network topology is a reduced set of inner-city sites with higher order sectorization.
Design issues of arithmetic structures in adiabatic logic
Authors: Teichmann Ph. , Fischer J. , Chouard F. , Schmitt-Landsiedel D.
Published: April 2010

Abstract. Since adiabatic logic uses a supply that incorporates both supply voltage and clock signal in one line, adiabatic logic systems have a built-in micro-pipelined architecture. Considering this fact, different design constraints have to be observed compared to static CMOS designs. Complex arithmetic building blocks, like multipliers, mainly consist of adders. Therefore, a comparison of adder structures is performed. Based on these results, multipliers and complex systems can be built. A Discrete Cosine Transformation (DCT) is taken as example for an arithmetic system. Comparing an adiabatic logic implementation of a DCT to its static CMOS counterpart, a significant saving factor of more than 10 can be achieved with the adiabatic system.
Design of UWB pulse radio transceiver using statistical correlation technique in frequency domain
Authors: Anis M. , Tielert R.
Published: April 2010

Abstract. In this paper, we propose a new technique to extract low power UWB pulse radio signals, near to noise level, using statistical correlation technique in frequency domain. The receiver consists of many narrow bandpass filters which extract energy either from transmitted UWB signal, interfering channels or noise. Transmitted UWB data can be eliminated by statistical correlation of multiple bandpass filter outputs. Super-regenerative oscillators, tuned within UWB spectrum, are designed as bandpass filters. Summers and comparators perform statistical correlation.
Visualisierung analoger Schaltungen durch 3-D Animation von transienten SPICE-Simulationen
Authors: Becker J. , Manoli Y.
Published: April 2010

Abstract. Für das Zeichnen analoger Schaltpläne wird oft versucht, die Potentialverteilung in der entsprechenden Schaltung auszunutzen, um eine Platzierung der Bauteile nach abfallendem Potential vorzunehmen. Mit Hilfe von Computerunterstützung gelingt es, eine verallgemeinerte dreidimensionale Platzierungsstrategie anzuwenden, die allein auf Grund der Potentialwerte einer Schaltung die automatische Generierung einer technisch exakten Potentialdarstellung erlaubt. Somit ist es möglich, die Ergebnisse von transienten SPICE-Simulationen in jedem Zeitschritt darzustellen und eine Animation des zeitlichen Verhaltens zu erzeugen. Die Umsetzung dieser Methode zur Einbettung in eine webbasierte Lern – und Arbeitsplattform wird im Folgenden erläutert.
Flat Fading in Mittelwellen-DRM-Gleichwellennetzen
Authors: Müller B. , Philipp J.
Published: April 2010

Abstract. Digitale Rundfunksysteme mit OFDM-Mehrträgerverfahren wie T-DAB, DVB-T und DRM wurden speziell entwickelt, um auch bei Mehrwegeausbreitung einen guten Empfang zu gewährleisten. Mit diesem Verfahren wurde auch der Aufbau von Gleichwellennetzen (SFNs) möglich. In solchen Gleichwellennetzen wird durch die Überlagerung der Signalanteile von unterschiedlichen Sendern mit verschiedenen Laufzeiten ein frequenzselektives Fading verursacht. Diese Überlagerung beeinträchtigt die Empfangsqualität nicht, solange die Kohärenzbandbreite (Kehrwert des Laufzeitunterschiedes) klein gegenüber der Signalbandbreite ist. Diese Bedingung ist meist bei den Systemen T-DAB und DVB-T erfüllt, bei denen die Signalbandbreite in der Größenordnung von 106 Hz liegen. Im DRM-System ist dagegen die Signalbandbreite auf wenige kHz beschränkt. Dadurch kann das „selektive“ Fading leicht das komplette Signal beeinträchtigen und somit bei großen Wellenlängen auch weite Gebiete erfassen. Zur Klärung, welche Maßnahmen getroffen werden können, um dennoch ein robustes DRM-Gleichwellennetzes auf Mittelwelle zu betreiben, wurden die Interferenz-Effekte eines Gleichwellennetzes mit zwei Sendern theoretisch modelliert und durch Feldmessungen in einem realen Gleichwellennetz mit zwei synchron arbeitenden Sendern im Gebiet zwischen Kaiserslautern und Mainz untersucht. Multicarrier digital broadcasting systems like T-DAB, DVB-T and DRM are designed to provide reception especially in multipath environments. At the same time this feature enables the implementation of single frequency networks (SFNs). In these, the superposition of the signals arriving from the different transmitters with different delays gives rise to interference in the form of frequency selective fading. This does not impair reception quality as long as the coherence bandwidth (the reciprocal of the time delay difference) is small compared to the signal bandwidth. This condition in most cases is safely met in T-DAB and DVB-T networks where the signal bandwidth is of the order of 106 Hz. In the DRM system the signal bandwidth however is confined to a few kHz only. Thus "selective" fading may easily affect the whole signal and, due to the large wave length, extend to comparatively large areas. To clarify which provisions have to be met to nevertheless render the operation of medium wave DRM SFNs feasible the interference effects in a two-transmitter SFN have been modelled theoretically and evaluated by field measurements in a real network consisting of synchronized transmitters sited near Kaiserslautern and Mainz.
Measurements of Cosmic Magnetism with LOFAR and SKA
Authors: Beck R.
Published: April 2010

Abstract. The origin of magnetic fields in stars, galaxies and clusters is an open problem in astrophysics. The next-generation radio telescopes Low Frequency Array (LOFAR) and Square Kilometre Array (SKA) will revolutionize the study of cosmic magnetism. "The origin and evolution of cosmic magnetism" is a key science project for SKA. The planned all-sky survey of Faraday rotation measures (RM) at 1.4 GHz will be used to model the structure and strength of the magnetic fields in the intergalactic medium, the interstellar medium of intervening galaxies, and in the Milky Way. A complementary survey of selected regions at around 200 MHz is planned as a key project for LOFAR. Spectro-polarimetry applied to the large number of spectral channels available for LOFAR and SKA will allow to separate RM components from distinct foreground and background regions and to perform 3-D Faraday tomography of the interstellar medium of the Milky Way and nearby galaxies. – Deep polarization mapping with LOFAR and SKA will open a new era also in the observation of synchrotron emission from magnetic fields. LOFAR's sensitivity will allow to map the structure of weak, extended magnetic fields in the halos of galaxies, in galaxy clusters, and possibly in the intergalactic medium. Polarization observations with SKA at higher frequencies (1–10 GHz) will show the detailed magnetic field structure within the disks and central regions of galaxies, with much higher angular resolution than present-day radio telescopes.
LOFAR in Germany
Authors: Reich W.
Published: April 2010

Abstract. The LOw Frequency ARray – LOFAR – is a new fully digital radio telescope designed for frequencies between 30 MHz and 240 MHz centered in the Netherlands. In May 2006 ten German institutes formed the German LOng Wavelength consortium – GLOW – to coordinate its contributions and scientific interests to the LOFAR project. The first LOFAR station CS1 was installed in summer 2006 near Exloo/Netherlands. The second station IS-G1 is presently been placed in the immediate vicinity of the Effelsberg 100-m radio telescope near Bad Münstereifel/Germany. This contribution briefly describes the basic properties and aims of LOFAR, the aims of the GLOW consortium and the actual activities to install a LOFAR station at the Effelsberg site.
Contactless electromagnetic measuring system using conventional calibration algorithms to determine scattering parameters
Authors: Zelder T. , Rabe H. , Eul H.
Published: April 2010

Abstract. In this paper, a contactless measuring system for the determination of the S-parameters of planar circuits is presented. With a contactless measuring system it is possible to characterise a device-under-test (DUT) embedded in a planar circuit environment without cutting the planar transmission lines connecting the DUT. The technique utilizes four identical capacitive probes in conjunction with a vector network analyser (VNA). For the usage of electromagnetic probes compared to other coupling techniques like the electro-optic probing, there is no need for expensive and complex equipment in addition to the typical equipment of a common microwave laboratory. The S-parameters are determined accurately using conventional calibration methods. A simple analytical model for the representation of the basic characteristics is developed. Furthermore, the influences on the S-parameters as a result of a variation in the coupling are presented. With the knowledge of the system characteristics, an accurate contactless measurement system is set up. The comparison between conventional and contactless measurements in a frequency range of 1–20 GHz shows a very good agreement with a phase error smaller than 1°.
Airborne field strength monitoring
Authors: Bredemeyer J. , Kleine-Ostmann T. , Schrader T. , Münter K. , Ritter J.
Published: April 2010

Abstract. In civil and military aviation, ground based navigation aids (NAVAIDS) are still crucial for flight guidance even though the acceptance of satellite based systems (GNSS) increases. Part of the calibration process for NAVAIDS (ILS, DME, VOR) is to perform a flight inspection according to specified methods as stated in a document (DOC8071, 2000) by the International Civil Aviation Organization (ICAO). One major task is to determine the coverage, or, in other words, the true signal-in-space field strength of a ground transmitter. This has always been a challenge to flight inspection up to now, since, especially in the L-band (DME, 1GHz), the antenna installed performance was known with an uncertainty of 10 dB or even more. In order to meet ICAO's required accuracy of ±3 dB it is necessary to have a precise 3-D antenna factor of the receiving antenna operating on the airborne platform including all losses and impedance mismatching. Introducing precise, effective antenna factors to flight inspection to achieve the required accuracy is new and not published in relevant papers yet. The authors try to establish a new balanced procedure between simulation and validation by airborne and ground measurements. This involves the interpretation of measured scattering parameters gained both on the ground and airborne in comparison with numerical results obtained by the multilevel fast multipole algorithm (MLFMA) accelerated method of moments (MoM) using a complex geometric model of the aircraft. First results will be presented in this paper.
Shielding effectiveness of original and modified building materials
Authors: Frenzel T. , Stumpf J. , Koch M.
Published: April 2010

Abstract. This contribution deals with the determination of the shielding effectiveness of building materials used for office, factory and government buildings. Besides the examination of standard materials, measurements were also performed on modified materials, e.g. ferro concrete with enhanced shielding effectiveness due to a changed mixture or structure of the reinforcement. The measurements of original and modified materials were carried out in a fully anechoic room (FAR) according to IEEE 299-1997 from 80 MHz up to 10 GHz.
Design of Sievenpiper HIS for use in planar broadband antennas by means of effective medium theory
Authors: Hampel S.K. , Schmitz O. , Klemp O. , Eul H.
Published: April 2010

Abstract. The claim for multistandard operating handsets of small physical size as well as the ever increasing demand for higher data rates require new broadband operating antennas. Because of the widespread use of especially planar broadband antennas a lot of factors influencing the characteristic antenna parameters have to be regarded. Furthermore, aspects regarding the electromagnetic compatibility inside the handheld as well as the protection of biological systems, e.g. the user of a mobilephone, have to be payed attention to. An electromagnetic structure which allows for protection by means of shielding as well as enhances the antennas efficiency by providing unique electromagnetic properties are the so called Sievenpiper High Impedance Surfaces (HIS) invented by Sievenpiper (1999). This paper will present the theory and the well known design equations for those structures. An investigation by means of simulation tools and measurement setups will be done to approve the accuracy of the theoretical results. Here measurement results of the impedance and radiation properties of a planar log.-per. four-arm antenna equiped in conjunction with a fabricated prototype Sievenpiper HIS will be presented.
Calibration method for direct conversion receiver front-ends
Authors: Müller R. , Jentschel H.-J.
Published: April 2010

Abstract. Technology induced process tolerances in analog circuits cause device characteristics different from specification. For direct conversion receiver front-ends a system level calibration method is presented. The malfunctions of the devices are compensated by tuning dominant circuit parameters. Thereto optimization techniques are applied which use measurement values and special evaluation functions.
Macro-modelling via radial basis functionen nets
Authors: Wiegand C. , Fischer C. , Kazemzadeh R. , Hedayat C. , John W. , Hilleringmann U.
Published: April 2010

Abstract. By the rising complexity and miniaturisation of the device's dimensions, the density of the conductors increases considerably. Referring to this, locally transient interactions between single physical values become apparent. Therefore, for the investigation and optimisation of integrated circuits it is essential to develop suitable models and simulation surroundings which allow for memory and time-efficient calculation of the behaviour. By means of the dynamic reconstruction theory and the radial basis functions nets the so-called black box models are provided. The description of black box models is derived from the input and output behaviour or so-called time series of a dynamic system. Concerning the time series, the black box model adapts its parameters via the extended Kalman filter. This paper provides a modelling approach that enables fast and efficient simulations.
Quantitative design space exploration of routing-switches for Network-on-Chip
Authors: Neuenhahn M. C. , Blume H. , Noll T. G.
Published: April 2010

Abstract. Future Systems-on-Chip (SoC) will consist of many embedded functional units like e.g. embedded processor cores, memories or FPGA like structures. These SoCs will have huge communication demands, which can not be fulfilled by bus-based communication systems. Possible solutions to this problem are so called Networks-on-Chip (NoC). These NoCs basically consist of network-interfaces which integrate functional units into the NoC and routing-switches which connect the network-interfaces. Here, VLSI-based routing-switch implementations are presented. The characteristics of these NoCs like performance and costs (e.g. silicon area respectively logic elements, power dissipation) depend on a variety of parameters. As a routing-switch is a key component of a NoC, the costs and performance of routing-switches are compared for different parameter combinations. Evaluated parameters are for example data word length, architecture of the routing-switch (parallel vs. centralized implementation) and routing-algorithm. The performance and costs of routing-switches were evaluated using an FPGA-based NoC-emulator. In addition different routing-switches were implemented using a 90 nm standard-cell library to determine the maximum clock frequency, power-dissipation and area of a VLSI-implementation. The power consumption was determined by simulating the extracted layout of the routing-switches. Finally, these results are benchmarked to other routing-switch implementations like Aetheral and xpipes.
Ein Unscented Kalman Filter zur Schätzung von Schaltungsnichtidealitäten eines zeitkontinuierlichen Sigma-Delta Wandlers mit impliziter Dezimation
Authors: Buhmann A. , Keller M. , Maurer M. , Ortmanns M. , Manoli Y.
Published: April 2010

Abstract. Nichtidealitäten einer Schaltung, wie z.B. nicht ideale Charakteristik des Operationsverstärkers und Streuungen in den Filterkoeffizienten, sind dahingehend bekannt die Effizienz von zeitkontinuierlichen Sigma-Delta Wandlern in drastischer Weise zu reduzieren. Daher stellt diese Veröffentlichung eine mögliche Methode vor, um die genannten Nichtidealitäten durch eine Schätzung mit Hilfe eines Unscented Kalman Filters zu bestimmen und in einem möglichen weiteren Schritt zu korrigieren. Des Weiteren kann durch eine leichte Modifikation des vorgestellten Algorithmus auch gleichzeitig eine implizite Dezimation des Ausgangssignals durchgeführt werden. Hierdurch wird die Gesamteffizienz des vorgestellten Ansatzes gesteigert, da kein zusätzlicher Dezimationsfilter mehr benötigt wird. Simulationsergebnisse des Filteralgorithmus zeigen die prinzipielle Funktion des Algorithmus.
A 3rd-order current-mode filter in 0.12 μm CMOS
Authors: Kolm R. , Zimmermann H.
Published: April 2010

Abstract. For software radio applications in system-on-chips, a 3rd-order current-mode Butterworth filter in 120 nm CMOS is realized. This filter is used for reconstruction purposes between a current-steering DAC and a current-mode mixer. Power can be reduced by using a current-mode architecture. The cut-off frequency of this filter is switchable between 1 MHz and 4 MHz, the current consumption is 4.5 mA at VDD=1.5 V, the inband noise density is 100 pA/√Hz and it has a dynamic range up to 65 dB.
Impact of on-chip inductance on power supply integrity
Authors: Eireiner M. , Henzler S. , Zhang X. , Berthold J. , Schmitt-Landsiedel D.
Published: April 2010

Abstract. Based on product related scenarios, the impact of on-chip inductance on power supply integrity is analyzed. The impact of varying current profiles is shown to be minimal. In a regular power grid with regular bump connections, the impact of on-chip inductance on the cycle average of the supply voltage can be neglected, even for a worst case estimation of on-chip inductance. Whereas, the maximum transient power supply drop can be significantly underestimated by neglecting on-chip inductance. The impact of on-chip inductance in a System-on-Chip (SoC) environment also can be neglected if the on-chip inductance is conservativly estimated.
Physical IC debug – backside approach and nanoscale challenge
Authors: Boit C. , Schlangen R. , Glowacki A. , Kindereit U. , Kiyan T. , Kerst U. , Lundquist T. , Kasapi S. , Suzuki H.
Published: April 2010

Abstract. Physical analysis for IC functionality in submicron technologies requires access through chip backside. Based upon typical global backside preparation with 50–100 µm moderate silicon thickness remaining, a state of the art of the analysis techniques available for this purpose is presented and evaluated for functional analysis and layout pattern resolution potential. A circuit edit technique valid for nano technology ICs, is also presented that is based upon the formation of local trenches using the bottom of Shallow Trench Isolation (STI) as endpoint for Focused Ion Beam (FIB) milling. As a derivative from this process, a locally ultra thin silicon device can be processed, creating a back surface as work bench for breakthrough applications of nanoscale analysis techniques to a fully functional circuit through chip backside. Several applications demonstrate the power and potential of this new approach.
Modelling dielectric and magnetic properties of ferroconcrete
Authors: Frenzel T. , Koch M.
Published: April 2010

Abstract. This contribution discusses the modelling and parameterization of dielectric and magnetic properties of ferroconcrete by using numerical electromagnetic field analysis software. The software is based on the Method of Moments (MoM). The shielding effectiveness (SE) of the ferroconcrete DUT was already measured in a study by order of the government. According to these results, the ferroconcrete DUT is modelled and calculated. Therefore the DUT is subdivided into two parts. The first part represents the reinforcement mesh; the second part represents the lossy concrete with complex permittivity. Afterwards, the reflection and transmission properties of numerical analysed building materials are validated and compared with the measurement results in a frequency range of 30–1000 MHz.
Measurement of electromagnetic interference in time-domain
Authors: Braun S. , Frech A. , Russer P.
Published: April 2010

Abstract. Time-domain EMI measurement systems allow measurement time to be reduced by several orders of magnitude. In this paper a novel real-time operating time-domain EMI measurement system is presented. By the use of several analog-to-digital converters the dynamic range requested by the international EMC standards is achieved. A real-time operating digital signal processing unit is presented. The frequency band that is investigated is subdivided into several sub-bands. A novel implementation of the 9 kHz IF filter for the frequency 150 kHz to 1 GHz is presented. By this way the measurement time has been reduced by a factor of 8000 in comparison to conventional EMI receivers. During emission measurements performed with a modelled IF-bandwidth of 9 kHz the noise floor is decreased to −19 dBµV in the average detector mode by the implemented low noise power splitter. Measurements have been performed with the improved measurement system in the frequency range 30 MHz–1 GHz.
Considerations on the frequency resource of professional wireless microphone systems
Authors: Dortmund S. , Fehr M. , Rolfes I.
Published: April 2010

Abstract. This Paper presents the results of spectral observations in the UHF TV Bands IV and V from 470 MHz up to 862 MHz with focus on the TV-Channels 61 to 63 and 67 to 69. Concerning the discussions on \\citet{WRC} this frequency range is in great demand of several applications and is usually treated as a "white space" in the TV-Bands. According to typical scenarios, two different spectral loads will be presented considering the requirements of professional wireless microphone receivers with respect to in-band intermodulation.
Analysis and design of a composite left-/right-handed leaky wave antenna based on the H10 rectangular waveguide mode
Authors: Weitsch Y. , Eibert T. F.
Published: April 2010

Abstract. The presented "open" composite left-handed/right-handed (CRHLH) substrate integrated waveguide performs well as a low-profile leaky wave antenna. This design is distinguished due to the fact that it is derived from the approved equivalent circuit model of the H10 rectangular hollow waveguide mode. The wave propagation behaviour is visualised by the dispersion diagram calculated by two different methods, infinite periodic full-wave simulation and Matrix-Pencil analysis of driven field solutions. The periodic configuration is also analysed in terms of the Bloch impedance. Although FR-4 serves as substrate the antenna features an efficiency of about 50% to 60%. The radiation performance demonstrates nearly backfire to almost endfire scanning capability of the antenna by mere frequency variation. Broadside radiation is possible due to the balanced state at 4 GHz.
MIMO performance of a planar logarithmically periodic antenna with respect to measured channel matrices
Authors: Rabe H. , Kornek D. , Stege M. , Rolfes I.
Published: April 2010

Abstract. The increasing interest in wireless transmission of highest data rates for multimedia applications (e.g. HDTV) demands the use of communication systems as e.g. described in the IEEE 802.11n draft specification for WLAN including spatial multiplexing or transmit diversity to achieve a constant high data rate and a small outage probability. In a wireless communications system the transmission of parallel data stream leads to multiple input/multiple output (MIMO) systems, whose key parameters heavily depend on the properties of the mobile channel. Assuming an uncorrelated channel matrix the correlation between the multiplexed data streams is caused by the coupling of the antennas, so that the radiation element becomes an even more important part of the system. Previous work in this research area (Klemp and Eul, 2006) has shown that planar log.-per four arm antennas are promising candidates for MIMO applications providing two nearly decorrelated radiators, which cover a wide frequency range including both WLAN bands at 2.4 GHz and 5.4 GHz. Up to now the MIMO performance of this antenna is mainly analyzed by simulations. In this contribution measured channel matrices in a real office environment are studied in terms of the antenna's MIMO performance such as outage probability. The obtained results recorded by using a commercial platform are compared to the simulated ones.
Characterisation of human gait using a continuous-wave radar at 24 GHz
Authors: Hornsteiner C. , Detlefsen J.
Published: April 2010

Abstract. Human locomotion consists of a complex movement of various parts of the body. The reflections generated by body parts with different relative velocities result in different Doppler shifts which can be detected as a superposition with a Continuous-Wave (CW) Radar. A time-frequency transform like the short-time Fourier transform (STFT) of the radar signal allows a representation of the signal in both time- and frequency domain (spectrogram). It can be shown that even during one gait cycle the velocity of the torso, which constitutes the major part of the reflection, is not constant. Further a smaller portion of the signal is reflected from the legs. The velocity of the legs varies in a wide range from zero (foot is on the ground) to a velocity which is higher than that of the torso. The two dominant parameters which characterise the human gait are the step rate and the mean velocity. Both parameters can be deduced from suitable portions of the spectrogram. The statistical evaluation of the two parameters has the potential to be included for discrimination purposes either between different persons or between humans and other moving objects.
Effiziente Verfahren zur Parallelisierung von EMV-Simulationen für den Entwurfsprozess integrierter Schaltungen
Authors: Barke M. , Preisner T. , Mathis W.
Published: April 2010

Abstract. In dieser Arbeit wird mit einer parallelisierten Version des PCG-Verfahrens (preconditioned conjugate gradient method) eine effiziente Technik zur numerischen Lösung großer Gleichungssysteme vorgestellt. Der Anwendungsbereich ist dabei die Simulation numerischer Feldberechnungen (beispielsweise durch die Finite-Elemente-Methode). Es wird ferner auf eine Datenstruktur eingegangen, die für die spezielle Struktur der auftretenden Koeffizientenmatrizen geeignet ist.
Charakterisierung von CMOS RF Blöcken mittels Volterra-Reihen zur Optimierung des Designprozesses
Authors: Fei B. , Darrat A. H. , Mathis W.
Published: April 2010

Abstract. Im Rahmen dieser Arbeit werden die Volterra-Reihen zur Analyse der Nichtlinearität in RF Schaltungen verwendet, um den Designprozess für RF Systeme zu optimieren. Die auf Volterra-Reihen basierende Nichtlinearitätsanalyse wurde in eine Matlab-Toolbox implementiert. Diese Toolbox kann mittels Volterra-Reihen die symbolische Berechnung der Nichtlinearitätsparameter (harmonische Verzerrungen und Intermodulationsverzerrungen) eines RF Blocks für eine gegebene Architektur und Technologie durchführen. Danach können die symbolische Ausdrücke der Nichtlinearitätsparameter in Abhängigkeit von den Architekturparametern und Technologieparametern erhalten werden. Dies ermöglicht die Beschränkung der Wertebereiche der Architekturparameter und die Überprüfung auf die Erfüllung der Nichtlinearitätsspezifikationen für unterschiedliche Kombinationen von Architekturen und Technologien. Somit ist eine Beschränkung der Klassen der Architekturen und Technologien möglich. Die Toolbox wurde zur Verdeutlichung auf einen Low Noise Amplifier (LNA) der Inductive Source Degeneration (ISD) Architektur angewandt. Zur Verifikation wurde diese LNA-Schaltung auch in Cadence SpectreRF Design Tool simuliert.
Hardwarearchitektur für einen universellen LDPC Decoder
Authors: Beuschel C. , Pfleiderer H.-J.
Published: April 2010

Abstract. Im vorliegenden Beitrag wird eine universelle Decoderarchitektur für einen Low-Density Parity-Check (LDPC) Code Decoder vorgestellt. Anders als bei den in der Literatur häufig beschriebenen Architekturen für strukturierte Codes ist die hier vorgestellte Architektur frei programmierbar, so dass jeder beliebige LDPC Code durch eine Änderung der Initialisierung des Speichers für die Prüfmatrix mit derselben Hardware decodiert werden kann. Die größte Herausforderung beim Entwurf von teilparallelen LDPC Decoder Architekturen liegt im konfliktfreien Datenaustausch zwischen mehreren parallelen Speichern und Berechnungseinheiten, wozu ein Mapping und Scheduling Algorithmus benötigt wird. Der hier vorgestellte Algorithmus stützt sich auf Graphentheorie und findet für jeden beliebigen LDPC Code eine für die Architektur optimale Lösung. Damit sind keine Wartezyklen notwendig und die Parallelität der Architektur wird zu jedem Zeitpunkt voll ausgenutzt.
Influence of gate tunneling currents on switched capacitor integrators
Authors: Kraus W. , Schmitt-Landsiedel D.
Published: April 2010

Abstract. In order to achieve a higher level of integration in modern VLSI systems, not only the lateral geometrical dimensions have to be scaled. Lowering the supply voltage also requires scaling down the oxide thickness of the transistors. While the oxide thickness is scaled down proportionally with the supply voltage, the gate tunneling currents grow exponentially, which results in special issues concerning deviations in charge based analog and mixed signal circuitry. The influence of gate tunneling currents on this kind of circuits will be demonstrated at a fully differential switched capacitor integrator. The used process data is derived from the International Technology Roadmap for Semiconductors (ITRS Roadmap, 2006). The Parameter sets for the simulations are based on the Predictive Technology Model of the Arizona State University Modelling Group for the 65 nm Technology node (Predictive Technology Model, 2008).
An X-Band low-power and low-phase-noise VCO using bondwire inductor
Authors: Hu K. , Herzel F. , Scheytt J. C.
Published: April 2010

Abstract. In this paper a low-power low-phase-noise voltage-controlled-oscillator (VCO) has been designed and, fabricated in 0.25 μm SiGe BiCMOS process. The resonator of the VCO is implemented with on-chip MIM capacitors and a single aluminum bondwire. A tail current filter is realized to suppress flicker noise up-conversion. The measured phase noise is −126.6 dBc/Hz at 1 MHz offset from a 7.8 GHz carrier. The figure of merit (FOM) of the VCO is −192.5 dBc/Hz and the VCO core consumes 4 mA from a 3.3 V power supply. To the best of our knowledge, this is the best FOM and the lowest phase noise for bondwire VCOs in the X-band. This VCO will be used for satellite communications.
Array antennas design in dependence of element-phasing
Authors: Zichner R. , Chandra M.
Published: April 2010

Abstract. Array antennas are used in science as well as for commercial and military purposes. The used element antennas act in accordance to their desired uses, for example radars or stationer GPS satellites. Typical components are for example slotted waveguides, patches, yagi-antennas and helix-antennas. All these elements do stand out with their own characteristics based on their special applications. If these elements are formed into an array configuration, the effectiveness can be improved immensely. There is a relation between the array functions and the physical array properties like the element alignment (linear, planar, circular), distances between the elements and so on. Among the physical properties there are other attributes like phase or amplitude coefficients, which are of great significance. The aim of this study was to provide an insight into the problem of array design, as far as the antenna element phase is concerned. Along with this, array radiation characteristics effects are presented. With the help of the extracted cognitions beam forming behaviour can be shown and the array phase behaviour can be analysed. One of the main applications is to simulate the array characteristics, like the radiation characteristic or the gain, for displacements of the array feeding point. A software solution that simulates the phase shift of a given array pattern is sought to adjust the feeding point.
Evaluation of wave propagation effects for detection of vulnerable road users
Authors: Fackelmeier A. , Morhart C. , Biebl E. M.
Published: April 2010

Abstract. The protection of vulnerable road users (VRU) is a key issue of future driver assistance systems. An important point is to determine whether a VRU is visually hidden to the driver. This additional information is essential for the driver to prevent an accident or to reduce its severity. We show that by using a transponder attached at the VRU, wavelength dependent diffraction effects can be utilized to distinguish between visible and hidden VRUs. Several diffraction measurements were carried out taking place in open space areas with simple big scattering objects and in different road traffic scenarios demonstrating a reliability of nearly 100%. If future driver assistance systems for detecting VRUs are complemented with automotive electronics which enable distinction between visible and hidden VRUs, accidents can be avoided.
Analyse und Untersuchung der Quantisierungseffekte beim Goertzel-Filter
Authors: Tchegho A. , Gräb H. , Schlichtmann U. , Mattes H. , Sattler S.
Published: April 2010

Abstract. Digitale Filter können in praktischen Anwendungen nur mit endlicher Wortbreite realisiert werden. Deshalb müssen Quantisierungseffekte verstanden werden, um die Eigenschaften und die Performanz der digitalen Filter geeignet einstellen zu können. Die am stärksten beeinflussten Aspekte sind neben Frequenzgang, die Stabilität und das Signal-Rausch-Verhältnis. Zu geringe Wortbreiten führen zu drastischen Veränderungen der Filtereigenschaften. Eine zu konservativ gewählte Wortbreite hingegen, erhöht die Größe und somit die Anzahl der Operationen des Filters unnötigerweise. Ziel dieses Beitrages ist es, für eine bestimmte Filterklasse optimale Wortbreiten zu finden, welche sowohl die Anzahl der Berechnungen und damit Operationen minimieren als auch sicherstellen, dass vorgegebene Toleranzbereiche für spezifizierte Filtereigenschaften eingehalten werden können. Die Untersuchungen werden an einem Goertzel-Filter durchgeführt, welches aufgrund seiner effizienten Eigenschaften besonders für die spektrale Bewertung von Mixed-Signal Schaltungen und Systemen geeignet ist.
A new high-integrated weak field sensor for automotive applications
Authors: Thiessen T. , Prochaska M.
Published: April 2010

Abstract. Especially in the field of automotive applications smart sensor systems for magnetic field sensing face increasing requirements concerning low cost, low power consumption and high magnetic performance. Over the past years AMR sensors play a decisive role in this application area because of their robustness and stability. In the following a high-integrated smart sensor system for magnetic field sensing is presented. A novel approach for the detection of weak magnetic fields is shown, which is based on an AC-excitation of AMR elements. In contrast to common used sensors this concept is based on a nonlinear AMR element without Barber pole construction. By means of this methodology sensitivity as well as temperature and life time stability is significantly improved, while the production costs compared to common-used sensors are reduced. Within this novel approach new signal conditioning algorithms and analog circuit topologies are presented, which are able to meet low offset and low noise requirements.
An observational and numerical case study of a flash sea storm over the Gulf of Genoa
Authors: Orlandi A. , Pasi F. , Onorato L. F. , Gallino S.
Published: April 2010

Abstract. During the night between the 8 and 9 December 2006 the seawall of the Savona harbour (Liguria Region in north west of Italy) was overtopped by waves. In this work the "Savona flash sea storm" has been studied by analyzing the data recorded by meteo-marine observing stations and the data produced by high resolution meteo-marine numerical models. The data show that, due to the presence of a fast moving low pressure system, the event was characterized by a rapid transition and interaction between two different regimes of winds and related sea states. The results of the study suggest that the most damaging dynamics of the event could be correlated to a bi-modal structure of the wave spectrum. Based on this the authors suggest that a deeper study of the spectral structure of sea storms could lead to define new operational forecasting tools for the preventive evaluation of sea storms damaging potential.
Sensitivity study of surface wind flow of a limited area model simulating the extratropical storm Delta affecting the Canary Islands
Authors: Marrero C. , Jorba O. , Cuevas E. , Baldasano J. M.
Published: April 2010

Abstract. In November 2005 an extratropical storm named Delta affected the Canary Islands (Spain). The high sustained wind and intense gusts experienced caused significant damage. A numerical sensitivity study of Delta was conducted using the Weather Research & Forecasting Model (WRF-ARW). A total of 27 simulations were performed. Non-hydrostatic and hydrostatic experiments were designed taking into account physical parameterizations and geometrical factors (size and position of the outer domain, definition or not of nested grids, horizontal resolution and number of vertical levels). The Factor Separation Method was applied in order to identify the major model sensitivity parameters under this unusual meteorological situation. Results associated to percentage changes relatives to a control run simulation demonstrated that boundary layer and surface layer schemes, horizontal resolutions, hydrostaticity option and nesting grid activation were the model configuration parameters with the greatest impact on the 48 h maximum 10 m horizontal wind speed solution.
Qualitative analysis of precipiation distribution in Poland with use of different data sources
Authors: Walawender J. , Dyras I. , Łapeta B. , Serafin-Rek D. , Twardowski A.
Published: April 2010

Abstract. Geographical Information Systems (GIS) can be used to integrate data from different sources and in different formats to perform innovative spatial and temporal analysis. GIS can be also applied for climatic research to manage, investigate and display all kinds of weather data. The main objective of this study is to demonstrate that GIS is a useful tool to examine and visualise precipitation distribution obtained from different data sources: ground measurements, satellite and radar data. Three selected days (30 cases) with convective rainfall situations were analysed. Firstly, scalable GRID-based approach was applied to store data from three different sources in comparable layout. Then, geoprocessing algorithm was created within ArcGIS 9.2 environment. The algorithm included: GRID definition, reclassification and raster algebra. All of the calculations and procedures were performed automatically. Finally, contingency tables and pie charts were created to show relationship between ground measurements and both satellite and radar derived data. The results were visualised on maps.
Analysis of turbulence in fog episodes
Authors: Terradellas E. , Ferreres E. , Soler M. R.
Published: April 2010

Abstract. Many processes interact in a complex and highly non-linear way during the life cycle of fog, the turbulent transport being among them. Observations and analysis of turbulence are, then, fundamental to our understanding of the physical mechanisms involved with fog formation, evolution and dissipation. Data gathered by fast-response sonic anemometers are processed using wavelet methods in order to estimate turbulence parameters such as kinetic energy or fluxes during the successive stages of fog evolution.
Air mass origin and its influence over the aerosol size distribution: a study in SE Spain
Authors: Cabello M. , Orza J. A. G. , Galiano V.
Published: April 2010

Abstract. A k-means cluster analysis of 96 hour trajectories arriving in Southeast (SE) Spain at 3000, 1500 and 500 m for the 7-year period 2000–2006 has been performed to identify and describe the main flows arriving at the study area. The dependence of the aerosol size distribution on the air mass origin has been studied by using non-parametric statistics. There are statistically significant differences on aerosol size distribution and meteorological variables at surface level according to the identified clusters.
Origin and influence of PM10 in urban and in rural environments
Authors: Kerschbaumer A. , Lutz M.
Published: April 2010

Abstract. The paper presents an estimate of emission source influence on PM10 concentrations in Berlin. Particulate matter less than 10 μm in aerodynamic diameter (PM10) is a conglomerate of different chemical components related to distinct sources and physico-chemical processes in the atmosphere and lithosphere. Emission reduction thus has temporally and spatially varying effects on different scales. Urban PM10 concentrations are heavily influenced by long range transport (up to 70%) from remote source areas, whereas rural air pollution is strongly determined by urban emissions. By means of emission reduction scenario simulations with a chemistry-transport-model it has been found that on average two third of the urban background concentrations in Berlin are due to Berlin-specific emissions. This percentage varies strongly considering primary and secondary components: only about 5% of secondary PM10 concentrations are related to local emissions, while approximately 70% of primary concentrations stem from the urban sources. City related emissions influence homogenously the rural air-pollution concentrations, but with different ranges of influence.
Heavy rain events in the Western Mediterranean: an atmospheric pattern classification
Authors: Martínez C. , Campins J. , Jansà A. , Genovés A.
Published: April 2010

Abstract. Heavy rain is one of the most important high-impact weather phenomena that occasionally affect Mediterranean areas. The aim of this study is to achieve a classification of atmospheric patterns related to heavy rain events in both French and Spanish Mediterranean regions. The classification is made on some atmospheric fields (geopotential at 1000 hPa and at 500 hPa and temperature at 850 hPa) of HIRLAM-INM-0.5° operational analysis, for heavy rain events included in the High Impact Weather MEDEX database. It covers a period of roughly 7 and a half years, from January 1997 to May 2004. A Principal Components Analysis was conducted to reduce the number of variables. After that, by means of a Cluster Analysis, the heavy rain events are classified into 8 atmospheric patterns. The results show a good relationship between regions affected by heavy rain and atmospheric patterns, in the sense that the same atmospheric patterns usually produce heavy rain in different regions, and heavy rain in different regions is usually due to specific atmospheric patterns.
COST ES0602: towards a European network on chemical weather forecasting and information systems
Authors: Kukkonen J. , Klein T. , Karatzas K. , Torseth K. , Fahre Vik A. , San José R. , Balk T. , Sofiev M.
Published: April 2010

Abstract. The COST ES0602 action provides a forum for benchmarking approaches and practices in data exchange and multi-model capabilities for chemical weather forecasting and near real-time information services in Europe. The action includes approximately 30 participants from 19 countries, and its duration is from 2007 to 2011 (http://www.chemicalweather.eu/). Major efforts have been dedicated in other actions and projects to the development of infrastructures for data flow. We have therefore aimed for collaboration with ongoing actions towards developing near real-time exchange of input data for air quality forecasting. We have collected information on the operational air quality forecasting models on a regional and continental scale in a structured form, and inter-compared and evaluated the physical and chemical structure of these models. We have also constructed a European chemical weather forecasting portal that includes links to most of the available chemical weather forecasting systems in Europe. The collaboration also includes the examination of the case studies that have been organized within COST-728, in order to inter-compare and evaluate the models against experimental data. We have also constructed an operational model forecasting ensemble. Data from a representative set of regional background stations have been selected, and the operational forecasts for this set of sites will be inter-compared and evaluated. The Action has investigated, analysed and reviewed existing chemical weather information systems and services, and will provide recommendations on best practices concerning the presentation and dissemination of chemical weather information towards the public and decision makers.
Spatial distribution of PM1 and PM10 during Saharan dust episodes in Athens, Greece
Authors: Grigoropoulos K. N. , Nastos P. T. , Ferentinos G.
Published: April 2010

Abstract. The objective of this study is to present and analyse the spatial distribution of PM1 (particulate matter with diameter less than 1 μm) and PM10 (particulate matter with diameter less than 10 μm) within the greater area of Athens (GAA), Greece, during two extreme Saharan dust episodes in 2006 and 2008. Two portable detectors, based on light scattering method, were used to record the particulate matter concentrations. The samples were collected in the same morning hour of the day which coincided with the peak of vehicles traffic. We analysed the recorded data on normal days and on days with extreme Saharan dust events in order to find out the exceedances of the particulate matter concentrations. Using Kriging method, the spatial patterns of PM1 and PM10 concentrations were constructed for GAA. It is already known that particulate matter represent the main hazard in cardiovascular and respiratory syndromes within the most polluted cities of Europe, which confront high traffic problems, amplified by Saharan dust episodes, which are frequent especially in the Southern Europe, during spring time. The results of the performed analysis showed that during these episodes, PM concentrations over exceed the thresholds set by the European Union, exacerbating the human health in Athens.