L'objectif de cette thèse est d'étudier et d'améliorer une technique de réception numérique appelée turbo-égalisation et basée sur le principe turbo. Ce système est constitué de plusieurs fonctions qui traitent itérativement les différentes perturbations apportées par le canal de propagation. L'Interférences Entre Symboles (IES) est corrigée par un égaliseur particulier appelé annuleur d'interférences construit à l'aide de filtres optimisés selon le critère de Minimum d'Erreur Quadratique Moyenne (MEQM). Le bruit et l'IES résiduelle sont ensuite traités par un décodeur de canal. Chaque fonction produit une information souple sur les données émises qui est améliorée à chaque traitement. L'IES est ainsi éliminée progressivement au cours des itérations.<br /><br />Grâce à une analogie avec les modulations codées, nous expliquons l'influence du schéma d'entrelacement, qui peut être réalisé au niveau des bits ou des symboles de modulation, sur les performances de la turbo-égalisation selon les caractéristiques temporelles des canaux de propagation. D'autre part, afin d'obtenir des performances satisfaisantes sur un modèle de canal ionosphérique, dont les caractéristiques de propagation sont réputées difficiles, nous étudions les différentes structures et algorithmes d'adaptation possibles pour les égaliseurs présents dans la turbo-égalisation. Puis nous présentons des améliorations de la conversion Maire-binaire sans information a priori. Une optimisation du mapping pour la conversion Maire-binaire avec information a priori de la turbo-égalisation est proposée et conduit à un gain de performances en terme de Taux d'Erreurs Binaires. Enfin nous comparons la turbo-égalisation à trois techniques alternatives : un système avec turbo-décodage, la technique multiporteuse COFDM, et un turbo-détecteur à treillis réduit.

The purpose of this master thesis is to investigate the possibility to refine the control system of turbochargers in petrol engines by introducing turbo speed measurement. This thesis also investigates possible control enhancement from an electric wastegate actuator compared with a traditional pneumatic actuator. During the thesis work the control problem is divided into 3 sub systems: boost pressure controller, turbo speed controller, and electric actuator controller. The design procedure of the controllers follows model-based method in which a simulation model for engine and a simulation model for electric actuator are used. The designed controller is then implemented and evaluated in an engine test cell. The result of the thesis work shows that the electric wastegate actuator is preferred as it delivers consistent actuation speed and accurate positioning which favours model-based design that requires exact wastegate position. Although the purposed controller structure that uses turbo speed measurement cannot yet achieve faster generation of boost pressure by the end of the thesis work, the use of turbo speed sensor as controller feedback still shows potential to enhance the boost controller and ease the controller design, as the turbo speed measurement can reflect the boost pressure faster and is less sensitive to the disturbances in the air flow.

International Telemetering Conference Proceedings / October 22-25, 2001 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Traditional communication hardware has focused on modular architectures. Now, with the incoming high speed DSP and FPGAs a shift from traditional modular architecture to reconfigurable architecture has taken place. The nature of this architecture allows to optimize various telemetry applications in a single platform. This paper describes a reconfigurable multi channel communication system.

No description available.

No description available.

<p>In some turbochargers, boost pressure is reduced by opening the wastegate valve. In a modern turbo charged car, the most common way for opening the wastegate is with a pneumatic actuator and an air control solenoid, controlled by the ECU. In the control systems studied the ECU utilizes a static feedforward and a PID controller, for the purpose of making the boost pressure follow its reference value. With no systematic method for tuning the controller, this can be time consuming, and a set of well defined experiments to determine PID parameters are desired.When test time in a real engine is limited or expensive, it is advantageousto work in a simulation environment before doing live tests. A model for thewastegate actuator and air control solenoid is developed in the thesis. This is used to simulate controller performance before any tests in a real car is performed.In the thesis a tuning method for the PID controller based on step responsesis proposed. The tuning method evaluated is the IMC-choice of controller fora second order system, and it has a single design parameter not given by theexperiments. The controller is shown to give desired behavior when the staticfeedforward is correct or has small error.</p>

In some turbochargers, boost pressure is reduced by opening the wastegate valve. In a modern turbo charged car, the most common way for opening the wastegate is with a pneumatic actuator and an air control solenoid, controlled by the ECU. In the control systems studied the ECU utilizes a static feedforward and a PID controller, for the purpose of making the boost pressure follow its reference value. With no systematic method for tuning the controller, this can be time consuming, and a set of well defined experiments to determine PID parameters are desired.When test time in a real engine is limited or expensive, it is advantageousto work in a simulation environment before doing live tests. A model for thewastegate actuator and air control solenoid is developed in the thesis. This is used to simulate controller performance before any tests in a real car is performed.In the thesis a tuning method for the PID controller based on step responsesis proposed. The tuning method evaluated is the IMC-choice of controller fora second order system, and it has a single design parameter not given by theexperiments. The controller is shown to give desired behavior when the staticfeedforward is correct or has small error.

This thesis studies advanced error control schemes using turbo-like codes, turbo-like coded modulations, turbo hybrid-ARQ (Automatic Repeat reQuest) schemes, and rate compatible puncturing techniques for reliable and adaptive commercial and tactical spread-spectrum communications, especially for code-division multiple access (CDMA) cellular systems and direct-sequence (DS) and frequency-hopping (FH) anti-jam systems. Furthermore, we utilize both the maximum-likelihood (ML) bounding techniques and convergence analysis to design and analyze various turbo-like coding schemes that show different behaviors in error performance from conventional trellis coding schemes. In the area of DS-CPM, we propose a DS concatenated coded CPM system for pulse-noise jamming channels and an anti-jam iterative receiver utilizing jammer state information. We also design a mixed concatenated CPM system that mixes CPM schemes with different convergence characteristics. In addition, we present the ML bound and convergence analysis for the jamming channel. In the area of FH-CPM, we propose anti-jam serially concatenated slow FH-CPM systems, whose phase is continuous during each hop interval, along with coherent and non-coherent iterative receivers. We also propose an iterative jamming estimation technique for the iterative receiver. In the area of multi-h CPM, we propose a power- and bandwidth-efficient serially concatenated multi-h CPM along with an appropriate iterative receiver structure. Serially concatenated multi-h CPM is shown to outperform single-h CPM. To design adaptive and versatile error control schemes using turbo-like codes for packet-data networks, we propose turbo hybrid-ARQ (HARQ) and rate compatible puncturing techniques for retransmission. In the area of turbo hybrid-ARQ, we propose a Type-I turbo HARQ scheme using a concatenated RS-turbo code and a packet combining technique for W-CDMA system to improve the performance of error and decoding latency. The W-CDMA system including the fast power control and coherent Rake receiver with a channel estimation technique for multipath fading channels is considered. Finally, in the area of rate compatible punctured turbo-like codes, we propose rate compatible punctured turbo (RCPT) codes and rate compatible punctured serially concatenated convolutional (RCPS) codes along with their puncturing methods. In addition, we propose Type-II RCPT-HARQ and RCPS-HARQ schemes to perform an efficient incremental redundancy retransmission.

Turbo Molecular pumps, abbreviated as TMP, can create a high vacuum environment for some special industries, especially the semiconductor and IC industries. The turbo blade design is one of the main technologies that affect the performance of a TMP. The object of this study is to investigate what kind of blade design parameters, e.g. blade angle, blade spacing, blade chord, blade velocity, etc., will affect the performance of TMP. It is hope that an analysis methodology of these parameters can be setup in the viewpoint of pumping rate curve. The results of this study will be useful for the design of TMP.

Thèse de doctorat : Télécommunications : Paris 12 : 2004. / Titre provenant de l'écran-titre.