bluuebunny/crossref_metadata_2025_split huggingface dataset:
Linear prediction methods for interference elimination in spread spectrum systems
Authors: Bernardini Angelo , Bernesi Marco , Salerno Mario 
Published: September 2008

AbstractThe performance of Pseudonoise (PN) Spread Spectrum System in the presence of narrow‐band interference can be improved by using various types of interference rejection filters.In this paper two different approaches are considered, the first based on Surface Acoustic Wave (SAW) devices and the second based on digital whitening using transversal filters.The reasons for the convenience of digital whitening are discussed and techniques for determining the coefficients of a linear interference suppression filter are described.Numerical results are presented on the characteristics of the linear filter and on its effectiveness in suppressing the interference when many different jamming and signaling conditions are considered.It is found that a critical point is the choice of the filter order which is related to a number of different design parameters: the signal‐to‐jammer power ratio, the noise power, the number of bands in which the jammer tones are splitted and the number of signal samples used in the coefficient estimation.
A migrating data driven architecture for signal processing
Authors: Brofferio Sergio , Mastronardi Giuseppe 
Published: September 2008

AbstractThe paper presents a migrating operations data‐driven multiprocessor architecture suited for digital signal processing.Three types of basic operations are first defined; this allows a simplified and efficient representation of algorithm execution in terms of Petri Nets.Data‐flow primitives, packets and operators, allow the implementation of the algorithm into an architecture, which is a generalization of the well known data driven architecture.Operand packets allow migration of operation computing from one processor to the neighbouring ones in case of nonuniform computation load within the system.The architecture of the data driven processor is then examined in its basic blocks and an example of operation migration control strategy is shown.Different architectures suited for specific trade‐off are proposed.
VLSI technologies: High performers and workhorses
Authors: Baldi Livio 
Published: September 2008

AbstractThe evolution of integrated circuit has been characterized in the past three decades by an exponential growth, both in performances and in circuit complexity, and it is showing no sign of slowing down. Several families of technologies have contributed to this explosive development: bipolar, GaAs and MOS, but only the last one has emerged as suitable for VLSI. However, each of the three has found its special field of application and is bringing its contribute to the total growth of circuit integration. It is very likely that all three shall coexist also in the next future, and will benefit from a mutual exchange of basic techniques. CMOS however will remain the main technology for VLSI, due to low power dissipation, flexibility and relatively low complexity. The critical issues which could hinder the further development of CMOS technology in the submicron range are essentially related to reliability, due to the increase in electric field and power density. The proposed solutions will probably imply new standards in supply voltages and slow down the progress in device speed.
Shallow junctions for ULSI technology
Authors: Solmi Sandro , Angelucci Renato , Merli Marco 
Published: September 2008

AbstractAbstract.Post‐implantation annealing conditions suitable to obtain very shallow p + ‐n and n + ‐p junctions with good electrical characteristics are critically examined by considering transient enhanced diffusion phenomena, dopant electrical activation, regrowth of the amorphous layer and radiation damage removal. Since activation energy of the diffusion processes is lower than that of damage recovery, high temperature rapid thermal annealings results, in principle, the best technique to fabricate shallow junction. The characteristics of diodes with junction depth of about 0.1 μm obtained by low energy implantation and annealing at 1000°C for 10 s are reported and discussed. Finally, ion implantation of B and As through a film of molybdenum or molybdenum silicide has been considered as a promising approach to shallow junction formations. Preliminary results related to devices fabricated by means of this self‐aligned procedure are presented.
Doped SiO2 deposition from TMP in APCVD
Authors: Bartholomew L. D. , Gralenski N. M. , Sisson J. C. , Pignatel G. U. 
Published: September 2008

AbstractIn this work we have investigated the feasibility of atmospheric pressure chemical vapor deposition of phosphorus and boron doped silicon oxides from a liquid source—namely TMP (tri‐methyl‐phosphite)—an alternative to phosphine as a P dopant source'. The most important results on process characterization, dopant incorporation, and film properties are presented. In addition to the easy operation of the liquid source, a remarkable improvement in step coverage has been found, in comparison with PSG deposition from conventional silane and phosphine chemistry.
Testing of E2PROM aging and endurance: A case study
Authors: Lanzoni Massimo , Menozzi Roberto , Olivo Piero , Riccò Bruno , Haardt Andrea 
Published: September 2008

AbstractThis work presents a detailed characterization of commercial E2PROMs performed by means of a new technique that allows non destructive monitoring of cell aging. Such a tech nique is based on accurate time control of the device power supply to stop the programming process, thus freezing the charge injected into the floating gate. Since a characteristic time is measured, the experiments can be performed varying other important parameters (in particular the supply voltage), whose influence on device endurance has been demonstrated. Thp method is also used to monitor the floating gate charging and discharging dynamics exploiting measurements of the drawn current.
Investigation of non‐local transport phenomena in small semiconductor devices
Authors: Gnudi Antonio , Odeh Farouk , Rudan Massimo 
Published: September 2008

AbstractThe hydrodynamic transport model based fin the generalized momentum and energy equations is used to simulate a n + ‐n‐n + one‐dimensional silicon device and the results are compared with Monte Carlo calculations. The non‐local effects are shown to become important for lengths of the order of a few tenths of a micrometer at applied voltages around 1.0–1.5 V. The hydrodynamic and Monte Carlo velocity and energy are generally in good agreement. Finally, the effects of the thermal conductivity and of the convective terms, in regions where large gradients are present, are investigated.
Information management in VLSI technology
Authors: Robertson John M. , Holwill Robert J. 
Published: September 2008

AbstractAny review of the development of microelectronics technology tends to emphasise improvements in packing density. However, there are also a number of other important parallel developments. This paper considers the factors which have contributed to an explosion of data concerning the device fabrication process. Ways in which that data may be structured and handled as technical or product information are reviewed and some of the implications for success are also out‐lined.
Two‐dimensional simulation of quantum well lasers
Authors: Song G. Hugh , Hess Karl , Kerkhoven Thomas , Ravaioli Umberto 
Published: September 2008

AbstractA versatile two‐dimensional simulator for various types of semiconductor lasers for both steady state and transients has been developed. The simulator is capable of spectral analysis of quantum‐well semiconductor lasers, such as gain‐spectrum analysis, as well as analysis of the two‐dimensional current flow and optical intensity patterns. The simulator is based on the drift‐diffusion model with full Fermi‐Dirac statistics for the transport equations as well as for the Poisson equation. Simulation of the thermionic emission current is required at the abrupt heterointerfaces of the quantum well. For the spectral analysis of quantum‐well lasers, we have used the photon rate equation for each Fabry‐Perot mode. For the optical intensity pattern, we have solved the two‐dimensional Helmholtz eigenvalue equation using the subspace iteration method. The transient simulation is done by the full backward‐Euler method in conjunction with the full Newton approach for the entire semiconductor equations. To demonstrate the simulator, a model GaAs‐AIGaAs graded‐index‐separate‐confinement‐heterostructure buried‐quantum‐well laser is analyzed.
Quasi‐two dimensional MESFET models application and validation
Authors: Snowden Christopher M. , Pantoja Renato R. 
Published: September 2008

AbstractA physical model of a gallium arsenide MESFET, based on an improved quasi‐two‐dimensional description of the transport in the device is presented. The formulation of the model includes a comprehensive treatment of the doping profile and allows sharp variations in the profile to be reflected in the device characteristics, unlike previously published models. The model is applied to the dc and microwave characterisation of MESFETs and microwave power amplifiers. Comparison with a wide range of measured data has permitted the validation of the models for a variety of small‐signal and power devices.
A computer aided procedure for experimental chamcterization and small signal modeling of MESFETs
Authors: Ferrero Andrea , Pisani Umberto 
Published: September 2008

AbstractA system which integrates in a single workstation the experimental procedures and data processing in order to carry out small‐signal equivalent circuits of microwave FET is presented.The workstation basic hardware consists of a HP8510 vector network analyzer, a dual programmable power supply, a dc bias switching box and a HP9000 series 300 desktop computer.While other approaches base the extraction of circuit elements mainly from scattering parameter measurements, the developed one implements several types of measurement techniques both in dc (pulsed), and in, necessary to directly extract several circuit parameters.Thus the optimization of a great number of parameters is avoided, which often leads either to an ill conditioned determination of element values, or to extraction of physically meaningless parameters.Furthermore by means of the described procedure several MESFET parameters tied to the technological process can be achieved.Some experimental results obtained with on wafer ion implantated devices show a very good model accuracy reached in the frequency band from 1 GHz to 18 GHz.
Alternative formulation of boundary‐element method for two‐dimensional electromagnetic boundary‐value problems
Authors: Gentili Gian Guido 
Published: September 2008

AbstractAn alternative formulation of the Boundary Element Method for internal two‐dimensional electromagnetic boundary‐value problems related to Helmholtz equation is presented.The formulation does not require the computation of special functions and the speed of computation is considerably faster than in standard formulations of BEM. The method of moments is used to solve the integral equation of BEM and all the integrals are computed analytically.Several examples of application of the method to the study of planar structures are shown and a comparison with the results obtained with standard BEM analysis is presented.
A new millimetre wave satellite system for land mobile communications
Authors: Valdoni Francesco , Ruggieri Marina , Vatalaro Francesco , Paraboni Aldo 
Published: September 2008

AbstractCellular systems are gaining wide acceptance. In Europe the GSM system is expected to provide service to more than 10 million users by the year 2000. Assuming that a demand for additional services at 64 kbit/s or so will not easily be satisfied either by the present GSM system or by advanced satellite systems at L‐band, this paper proposes a new satellite system at EHF (40150 GHz) to be integrated at the end of the decade with the GSM system or its descendants. First, the paper describes the main obstacles for the new system, in terms of channel characteristics and technology developments, and then illustrates a preliminary system design to show the technical feasibility in the proposed ten years time scale.
Mathematical approaches to electron device modelling for non‐linear microwave circuit design: State of the art and present trends
Authors: Filicori Fabio , Monaco Vito A. , Vannini Giorgio 
Published: September 2008

AbstractThe accuracy of CAD techniques for the design of non‐linear microwave circuits is strongly dependent on the features of the models used for the characterization of electron devices (i.e. MESFET, bipolar transistors, diodes etc.,.). At present, empirical equivalent circuits are widely used. These models, which are in many cases sufficiently accurate, require, however, quite refined numerical and measurement techniques to extract from measured data the parameters of a model which is strongly dependent on the particular physical structure of each device.Moreover, when using equivalent circuit models, the design of non‐linear microwave circuits must be carried out by using numerical optimization techniques. In this respect a simple mathematical model described in the frequency domain in terms of explicit equations between the electrical variables, would be preferable for the designer. Mathematical models, in fact, allow quite easy, direct procedures for circuit design. This paper deals with the problem of mathematical modelling of electron devices operating under large‐signal conditions at microwave frequencies. In particular, mathematical models based on the describing‐function and Volterra‐series approach are considered also taking into account their application to circuit design. The advantages of a recently proposed mathematical modelling approach based on mild assumptions valid for most types of electron devices, are also discussed in the paper.
Speech and image coding for digital communications
Authors: Guglielmo Mario , Modena Giulio , Montagna Roberto 
Published: September 2008

AbstractThe paper is presenting a sketch of the main results achieved in the recent years and of the ongoing activities (mainly within the Standardization Bodies) in the areas of audio and video coding for bandwidth reduction. The evolution of the telecommunication Field and the needs which originate the different standards are also considered.The paper is organized in two main chapters: the first one is dealing with the techniques for audio and speech coding while the second presents the main achievements in terms of Recommendations and consolidate algorithms for image coding. Concerning speech and audio coding the paper presents and overview of the coding techniques and then examines the different environments of transmissions (network and mobile communication), the bandwidths required to satisfy the considered applications and the defined speech quality evaluation methods. A similar approach has been used for video coding and the evolution of the coding techniques appearing in the CCITT Recommendations is presented. The ongoing activities within CCIR, CMIT, CCITT and ISO towards new worldwide standards are also outlined providing indications on the areas which will require further developments.
Integrated services digital networks: Narrowband networks
Authors: Mossotto Cesare 
Published: September 2008

AbstractThis paper deals with the deployment of the narrowband Integrated Services Digital Network, which is conceived as a significant rationalization of the existing public telecommunication networks, which include at present a number of different structures devoted to the various kinds of services.The main guidelines of ISDN evolution are depicted, starting with a short analysis of the expected wide range of TLC services, as this market is the main driving force for the deployment of new network architectures providing a powerful integrated access, a rapid service introduction and a high flexibility. The resulting reference network architecture is then described, highlighting the maximum possible integration of techniques and services, the unified access for the whole range of TLC services, the significant improvement of the user‐network signalling capabilities, the provision of high level network capabilities and the efficient communication among the various network entities. Some interworking and network dimensioning aspects, related to the gradual deployment of this new network architecture, are also examined, together with some consideration about further evolutionary steps.A second part of the paper is devoted to an analysis of ISDN functionalities, starting with a short survey of ISDN protocols (X.31 network access protocol, higher layers protocols, CCITT N. 7 network signalling for ISDN), which are the international standards on which this evolution is based. Circuit and packet ISDN switching facilities are then briefly examined, focusing on ISDN access functions, which are very important for both the access integration and the hardware cost reduction. A further important point examined concerns ISDN protocol testing and validation (for both terminals and switching offices), together with the performance evaluation of ISDN switching officies.The last part of the paper is devoted to a short survey of the present status of ISDN world development (pilot services, start of commercial services), starting from the European situation (France, Germany, United Kingdom, Italy etc.), examining the ISDN development in other Countries (United States, Japan, Canada and others) and giving finally some indications about the expected future plans.
Integrated services digital networks: Broadband networks
Authors: Listanti Marco , Roveri Aldo 
Published: September 2008

AbstractThis paper deals with the final goal of the evolutionary process of the public telecommunication networks towards broadband capabilities (B‐ISDN), process which is based on the adoption of the Asynchronous Transfer Mode (ATM).At first, a critical analysis is carried out about the transfer modes which gave rise to the definition of ATM. This analysis makes reference to three different and complementary aspects, i.e. the multiplexing technique, the switching principle and the protocol architecture.Then the current status of B‐ISDN is presented on the basis of the most recent results available from the standardization activity. In particular aichitectural aspects and traffic control issues are considered.
Broadband switching systems: First generation
Authors: Pattavina Achille 
Published: September 2008

AbstractSeveral generations of switching systems for broadband networks have been developed in the eighties. This paper describes the structures, the properties and performance Of the first generation of such systems known as banyan interconnection networks. Three classes of these networks are examined, that is unbuffered networks, buffered networks with internal queueing and buffered networks with output quequeing.
Terminals and signal processing in atm networks
Authors: Modena Giulio 
Published: September 2008

AbstractThe paper presents the research topics of the «Progetto Finalizzato Telecomunicazio‐ni» partially founded by CNR (National Council for Research) on the multi‐media terminals, video broadcast terminal and HDTV (High Definition Television) signal processing. It describes the main features of a full ATM Workstation, of ISDN multiservice terminal and digital video broadcast codec connected to ATM node. It presents also the studies on HDTV by simulation of algorithm.
Coherent optical FSK transmission systems
Authors: Prati Giancarlo 
Published: September 2008

AbstractCoherent optical systems are getting much closer to commercial realizations than expected only few years ago. Front‐running candidates for simplicity and effectiveness are FSK communication systems. Several reasons stand in favour of this system: most evident are direct modulation of semiconductor lasers, generation of two‐lobe spectrum or compact spectrum by simply setting the modulation index, possibility of envelope or discriminator detection, full compatibility with optical amplifiers due to constant optical envelope, direct application to subcar‐rier multiplexing with analog optical FM. In this paper we describe the basic FSK trasmission system, presenting the relative problems and illustrating possible different solutions for transmission and for the receiver, and concentrating on specific subsystems time by time, such as line coder, automatic frequency control, receiver balanced front‐end, post‐detection pre‐amplifier, discriminator and envelope detection, from both theoretical and implementation points of view.
Application of tricomi functions in the eigenvalue analysis of the circular gyrotropic waveguide
Authors: Ivanov Kamen P. , Georgiev Georgi N. 
Published: September 2008

AbstractThe complex Tricomi confluent hypergeometric functions Φ (a, c;x) are introduced as exact functions for propagation of normal TEommodes in circular guiding structures, containing coaxially positioned azimuthally magnetized ferrite layer of double‐connected cross‐section. An original form of characteristic equation of the ferrite‐fiiled coaxial waveguide is derived in terms of the arguments of Tricomi functions. Using the specially tabulated values of the latter, a numerical solution of this equation is accomplished, giving the eigenvalue spectrum and nonreciprocal phase characteristics of the structure. An analysis of its phase shifting capabilities is presented for a variety of geometry and ferrite parameters. The potentialities of the gyrotropic waveguide as digital nonreciprocal phaser, operating in theTE01mode, are discussed.
Space variant resolution ADCT still image coding
Authors: Imperato Mario Alessandro , Jacovitti Giovanni , Neri Alessandro 
Published: September 2008

AbstractStarting from the principle that the distorsion measure, representing the cost payed by the users for lossy reproducing an image, takes its maxima in correspondence of local minima of Shannon's Entropy, a space variant resolution coding method matched to the local content of the image is presented. A fidelity criterion based on the estimated kurtosis function of the image is then applied to drive the quantization phase of an ADCT coder. Finally, an enhanced version of the ISO/CCITT hierarchical progressive transmission mode is proposed and its perfomance evaluated on the basis of reference images.
Digital computer simulation of synthetic aperture systems and images
Authors: Camporeale Claudio , Galati Gaspare 
Published: September 2008

AbstractDigital computer simulation is a powerful tool for the design, the mission planning and the image quality analysis of advanced SAR Systems.«End‐to‐end» simulators describe the whole process of the SAR imaging including the generation of the coherent echoes and their processing and allow, unlike the «product simulators», to evaluate the effects of the various impairments on the final image.The main disadvantage of the «end‐to‐end» approach, as described in this paper, is the heavy computation burden; therefore, a new type of simulator is presented, attempting to reduce the burden but presenting a greater degree of completeness and realism than the SAR product simulators, already existing.An «end‐to‐end» simulator and an «intermediate» simulator are described and analyzed, with emphasis on their architecture and performance.