Méthodes de conception d’amplificateurs de puissance flexibles pour les applications spatiale

Méthodes de conception d’amplificateurs de puissance flexibles pour les applications spatiale PDF Author: David Sardin
Publisher:
ISBN:
Category :
Languages : fr
Pages : 456

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Book Description
Ce travail de thèse concerne l'amélioration du rendement des amplificateurs de puissance utilisés dans les équipements radiofréquence.Les besoins actuels dans le domaine des télécommunications spatiales imposent aux satellites de présenter des capacités de reconfigurabilité et de flexibilité en puissance. La finalité est d'une part, d'utiliser de manière optimale la puissanceDC disponible à bord et d'autre part, de permettre une évolution de la mission du satellite. Dans ce contexte, ce manuscrit présente le développement d'un amplificateur de puissance RF 30W à fort rendement basé sur le principe de la technique de l'envelope tracking. L'amplificateur d'enveloppe VHF ainsi proposé démontre d'excellentes performances en rendement et en bande passante en présence de signaux modulés à large bande.

Méthodes de conception d’amplificateurs de puissance flexibles pour les applications spatiale

Méthodes de conception d’amplificateurs de puissance flexibles pour les applications spatiale PDF Author: David Sardin
Publisher:
ISBN:
Category :
Languages : fr
Pages : 456

Get Book Here

Book Description
Ce travail de thèse concerne l'amélioration du rendement des amplificateurs de puissance utilisés dans les équipements radiofréquence.Les besoins actuels dans le domaine des télécommunications spatiales imposent aux satellites de présenter des capacités de reconfigurabilité et de flexibilité en puissance. La finalité est d'une part, d'utiliser de manière optimale la puissanceDC disponible à bord et d'autre part, de permettre une évolution de la mission du satellite. Dans ce contexte, ce manuscrit présente le développement d'un amplificateur de puissance RF 30W à fort rendement basé sur le principe de la technique de l'envelope tracking. L'amplificateur d'enveloppe VHF ainsi proposé démontre d'excellentes performances en rendement et en bande passante en présence de signaux modulés à large bande.

Conception et réalisation d'amplificateurs de puissance micro-ondes à l'état solide et à fort rendement pour des applications spatiales bande S et bande X

Conception et réalisation d'amplificateurs de puissance micro-ondes à l'état solide et à fort rendement pour des applications spatiales bande S et bande X PDF Author: Marc Zoyo
Publisher:
ISBN:
Category :
Languages : fr
Pages : 233

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Book Description
L'OBJECTIF DE CE TRAVAIL A ETE DE DETERMINER UNE METHODOLOGIE DE CONCEPTION ORIGINALE ET SYSTEMATIQUE D'AMPLIFICATEURS HYPERFREQUENCES DE PUISSANCE A TRES HAUT RENDEMENT, EN TECHNOLOGIE HYBRIDE ET CE POUR DES APPLICATIONS SPATIALES. LA PREMIERE PARTIE CONSTITUE UNE INTRODUCTION DETAILLANT LES DIVERS PHENOMENES RELATIFS A L'AMPLIFICATION DE PUISSANCE DANS LE DOMAINE DES HYPERFREQUENCES. UN EXEMPLE PARTICULIER DU FONCTIONNEMENT A FORT RENDEMENT, APPELE LA CLASSE F, EST EXPLICITE. LA DEUXIEME PARTIE TRAITE DE LA CARACTERISATION ET DE LA MODELISATION DE DIFFERENTS TYPES DE TRANSISTORS A EFFET DE CHAMP DE PUISSANCE. IL EST AINSI PROPOSE UNE NOUVELLE APPROCHE DE LA CARACTERISATION, BASEE SUR DES TRANSFORMATIONS LARGE BANDE D'IMPEDANCES, AFIN D'EXTRAIRE DES MODELES ELECTRIQUES EQUIVALENTS EN REGIMES LINEAIRE ET NON-LINEAIRE. LA TROISIEME PARTIE CONCERNE LA CONCEPTION ET LA REALISATION D'AMPLIFICATEURS HYBRIDES DE PUISSANCE A FORT RENDEMENT FONCTIONNANT EN BANDE X (8,2GHZ) ET CONSTITUES DE TRANSISTORS A EFFET DE CHAMP A HETEROSTRUCTURE (HFET). DES CORRELATIONS ENTRE LES RESULTATS EXPERIMENTAUX ET CEUX PREDITS PAR LES SIMULATIONS ONT PERMIS DE MONTRER UNE BONNE ADEQUATION. L'INFLUENCE DES CHARGES PRESENTEES AUX DEUX PREMIERS HARMONIQUES DU SIGNAL APPLIQUE SUR LE COMPORTEMENT DU HFET DE PUISSANCE EST ETUDIEE ET DISCUTEE. DANS LA DERNIERE PARTIE, LA PROCEDURE DE CONCEPTION DE CE TYPE D'AMPLIFICATEUR EST VALIDEE A L'AIDE DE DIVERSES APPLICATIONS TELS QUE DES AMPLIFICATEURS DE PUISSANCE FONCTIONNANT EN BANDE X OU EN BANDE S, A BASE DE TRANSISTORS PSEUDOMORPHIQUES A HAUTE MOBILITE ELECTRONIQUE (PHEMT)

Microwave Scanning Antennas: Apertures

Microwave Scanning Antennas: Apertures PDF Author: Robert C. Hansen
Publisher:
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 472

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Book Description


UCRL.

UCRL. PDF Author: U.S. Atomic Energy Commission
Publisher:
ISBN:
Category : Government publications
Languages : en
Pages : 26

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Book Description


Quantum Communications and Cryptography

Quantum Communications and Cryptography PDF Author: Alexander V. Sergienko
Publisher: CRC Press
ISBN: 1420026607
Category : Science
Languages : en
Pages : 248

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Book Description
All current methods of secure communication such as public-key cryptography can eventually be broken by faster computing. At the interface of physics and computer science lies a powerful solution for secure communications: quantum cryptography. Because eavesdropping changes the physical nature of the information, users in a quantum exchange can easily detect eavesdroppers. This allows for totally secure random key distribution, a central requirement for use of the one-time pad. Since the one-time pad is theoretically proven to be undecipherable, quantum cryptography is the key to perfect secrecy. Quantum Communications and Cryptography is the first comprehensive review of the past, present, and potential developments in this dynamic field. Leading expert contributors from around the world discuss the scientific foundations, experimental and theoretical developments, and cutting-edge technical and engineering advances in quantum communications and cryptography. The book describes the engineering principles and practical implementations in a real-world metropolitan network as well as physical principles and experimental results of such technologies as entanglement swapping and quantum teleportation. It also offers the first detailed treatment of quantum information processing with continuous variables. Technologies include both free-space and fiber-based communications systems along with the necessary protocols and information processing approaches. Bridging the gap between physics and engineering, Quantum Communications and Cryptography supplies a springboard for further developments and breakthroughs in this rapidly growing area.

Ultra Wide Band Antennas

Ultra Wide Band Antennas PDF Author: Xavier Begaud
Publisher: John Wiley & Sons
ISBN: 1118586573
Category : Technology & Engineering
Languages : en
Pages : 217

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Book Description
Ultra Wide Band Technology (UWB) has reached a level of maturity that allows us to offer wireless links with either high or low data rates. These wireless links are frequently associated with a location capability for which ultimate accuracy varies with the inverse of the frequency bandwidth. Using time or frequency domain waveforms, they are currently the subject of international standards facilitating their commercial implementation. Drawing up a complete state of the art, Ultra Wide Band Antennas is aimed at students, engineers and researchers and presents a summary of internationally recognized studies.

Advances in Turbulence XII

Advances in Turbulence XII PDF Author: Bruno Eckhardt
Publisher: Springer
ISBN: 9783662519325
Category : Science
Languages : en
Pages : 0

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Book Description
Lagrangian aspects.- Lagrangian modeling and properties of particles with inertia.- Effect of Faxén forces on acceleration statistics of material particles in turbulent flow.- Lagrangian analysis of turbulent convection.- Linear and angular dynamics of an inertial particle in turbulence.- Collision rate between heavy particles in a model turbulent flow.- From cloud condensation nuclei to cloud droplets: a turbulent model.- Lagrangian statistics of inertial particles in turbulent flow.- Lagrangian statistics of two–dimensional turbulence in a square container.- Measurement of Lagrangian Particle Trajectories by Digital in-line Holography.- 3-D Particle Tracking Velocimetry (PTV) in gas flows using coloured tracer particles.- Two-particle dispersion in 2D inverse cascade turbulence and its telegraph equation model.- Numerical simulations of particle dispersion in stratified flows.- Instability and Transition.- Experimental study of the von Kármán flow from = 10 to 10: spontaneous symmetry breaking and turbulent bifurcations.- Flow reversals in a vertical channel.- Linear Instability of Streamwise Corner Flow.- DNS of turbulent plane Couette flow with emphasis on turbulent stripe.- Geometry of state space in plane Couette flow.- Linear and nonlinear instabilities of sliding Couette flow.- Localization in plane Couette edge dynamics.- Nonlinear optimal perturbations in plane Couette flow.- Order parameter in laminar-turbulent patterns.- Pattern formation in low Reynolds number plane Couette flow.- Quasi-stationary and chaotic convection in low rotating spherical shells.- Linear stability of 2D rough channels.- Transient turbulent bursting in enclosed flows.- On New Localized Vortex Solutions in the Couette-Ekman Layer.- Shear instabilities in Taylor-Couette flow.- Particle Tracking Velocimetry in Transitional Plane Couette Flow.- Experimental study of coherent structures in turbulent pipe flow.- Forced localized turbulence in pipe flows.- From localized to expanding turbulence.- Influence of test-rigs on the laminar-to-turbulent transition of pipe flows.- Interaction of turbulent spots in pipe flow.- Large-scale transitional dynamics in pipe flow.- Nonlinear coherent structures in a square duct.- Quantitative measurement of the life time of turbulence in pipe flow.- Experimental investigation of turbulent patch evolution in spatially steady boundary layers.- Interaction of noise disturbances and streamwise streaks.- Linear generation of multiple time scales by 3D unstable perturbations.- Convection at very high Rayleigh number: signature of transition from a micro-thermometer inside the flow.- Estimating local instabilities for irregular flows in the differentially heated rotating annulus.- Search for the “ultimate state” in turbulent Rayleigh-Bénard convection.- Rayleigh–Taylor instability in two dimensions and phase-field method.- Split energy cascade in quasi-2D turbulence.- Stabililty and laminarisation of turbulent rotating channel flow.- The vortical flow pattern exhibited by the channel flow on a rotating system just past transition under the influence of the Coriolis force.- Transient evolution and high stratification scaling in horizontal mixing layers.- Control of turbulent flows.- Toward cost-effective Control of Wall Turbulence for Skin Friction Drag Reduction.- Active control of turbulent boundary layer using an array of piezo-ceramic actuators.- Flat plate turbulent boundary-layer control using vertical LEBUs.- Estimation of the spanwise wall shear stress based on upstream information for wall turbulence control.- Interactions between vortex generators and a flat plate boundary layer. Application to the control of separated flows..- Modulated global mode of a controlled wake.- Swirl effects in turbulent pipe flow.- Control of an axisymmetric turbulent wake by a pulsed jet.- Direct Numerical Simulations of turbulent mixed convection in enclosures with heated obstacles.-

MIMO

MIMO PDF Author: Alain Sibille
Publisher: Academic Press
ISBN: 0123821959
Category : Technology & Engineering
Languages : es
Pages : 385

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Book Description
Foreword from Arogyaswami Paulraj, Professor (Emeritus), Stanford University (USA) - The first book to show how MIMO principles can be implemented in today's mobile broadband networks and components - Explains and solves some of the practical difficulties that arise in designing and implementing MIMO systems - Both theory and implementation sections are written in the context of the most recent standards: IEEE 802.11n (WiFi); IEEE 802.16 (WIMAX); 4G networks (3GPP/3GPP2, LTE)

Introduction to ISDN

Introduction to ISDN PDF Author:
Publisher: Wiley-Blackwell
ISBN:
Category : Computers
Languages : en
Pages : 100

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Book Description


Signal Processing for Communications

Signal Processing for Communications PDF Author: Paolo Prandoni
Publisher: Collection Savoir suisse
ISBN: 2940222207
Category : Signal processing
Languages : en
Pages : 392

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Book Description
With a novel, less classical approach to the subject, the authors have written a book with the conviction that signal processing should be taught to be fun. The treatment is therefore less focused on the mathematics and more on the conceptual aspects, the idea being to allow the readers to think about the subject at a higher conceptual level, thus building the foundations for more advanced topics. The book remains an engineering text, with the goal of helping students solve real-world problems. In this vein, the last chapter pulls together the individual topics as discussed throughout the book into an in-depth look at the development of an end-to-end communication system, namely, a modem for communicating digital information over an analog channel.