Le secteur de communications sécurisés et portables connait une véritable révolution avec l’apparition des plateformes dites radios logiciels (Software Defined Radios, SDRs). Les performances exceptionnelles de ces systèmes sont les résultats d’une interaction assez complexe et souvent peu évidente entre le logiciel embarqué, le circuit de traitement numérique et les blocs mixtes analogiques/RF. Cette complexité limite la testabilité du produit fini. La méthodologie de test utilisée actuellement a atteint ses limites dues au cout élevé, le long temps de test et le bas degré de généralisation. De plus, les plateformes SDRs peuvent évoluer sur le terrain et elles vont supporter des standards et des scénarios qui n’ont pas été considérés pendant le la phase de conception. Donc, une stratégie de test sur le terrain (en ligne) n’est plus une caractéristique optionnelle mais une nécessité. Dans ce contexte, le but de notre recherche est d’inventer et développer une méthodologie de test capable de garantir le bon fonctionnement d’une plateforme SDR après la production et pendant sa vie. Notre objectif final est de réduire le coût du test en profitant de la reconfigurabilité de la plateforme. Pour les radios tactiques qui doivent être mises à jour sur le terrain sans équipement spécial, les stratégies Built-In Self-Test (BIST) sont, sans doute, la seule moyenne de garantir la conformité aux spécifications. Dans cette mémoire, nous introduisons une nouvelle architecture de test RF BIST qui utilise la technique de de sous-échantillonnage nonuniform à la sortie de l’émetteur (TX) d’une SDR afin d’évaluer la conformité de la masque spectrale. Notre solution s’appuie sur une implémentation autonome, est modulable et peut être appliquée pour le test sur le terrain avec des modifications minimes. Par rapport aux autres techniques de test analogiques/RF, cet approche ne dépends pas de la architecture du TX, ni d’un modèle ad-hoc, ce qui est idéale pour le test des SDRs. / The advent of increasingly powerful Integrated Circuits (IC) has led to the emergence of the Software Defined Radio (SDR) concept, which brought the sector of secured mobile communications into a new era. The outstanding performance of these systems results from optimal trade-offs among advanced analog/Radio Frequency (RF) circuitry, high-speed reconfigurable digital hardware and sophisticated real-time software. The inherent sophistication of such platforms poses a challenging problem for product testing. Currently deployed industrial test strategies face rising obstacles due to the costlier RF test equipment, longer test time and lack of flexibility. Moreover, an SDR platform is field-upgradeable, which means it will support standards and scenarii not considered during the design phase. Therefore, an in-field test strategy is not anymore 'a nice to have' feature but a mandatory requirement. In this context, our research aims to invent and develop a new test methodology able to guarantee the correct functioning of the SDR platform post-fabrication and over its operational lifetime. The overall aim of our efforts is to reduce post-manufacture test cost of SDR transceivers by leveraging the reconfigurability of the platform.For tactical radio units that must be field-upgradeable without specialized equipment, Built-in Self-Test (BIST) schemes are arguably the only way to ensure continued compliance to specifications. In this study we introduce a novel RF BIST architecture which uses Periodically Nonuniform Sampling (PNS2) of the transmitter (TX) output to evaluate compliance to spectral mask specifications. Our solution supports a stand-alone implementation, is scalable across a wide set of complex specifications and can be easily applied for in-field testing with small added hardware. Compared to existing analog/RF test techniques, this approach is not limited to a given TX architecture and does not rely on an ad-hoc TX model, which makes it ideal for SDR testing.

Localization inside the human body using radio frequency (RF) transmission is gaining importance in a number of applications such as Capsule Endoscopy. The accuracy of RF localization depends on the technology adopted for this purpose. The two most common RF localization technologies use received signal strength (RSS) and time-of-arrival (TOA). This research presents a comparison of the accuracy of TOA and RSS based localization inside human tissue using computational techniques for simulation of radio propagation inside human tissues. Computer simulation of the propagation of radio waves inside the human body is extremely challenging and computationally intensive. We designed a basic, MATLAB coded, finite difference time-domain (FDTD) for the radio propagation in and around the human body and compared the results obtained from this software with the commonly used and commercially available Finite Element Method (FEM) modeling in Ansoft HFSS (ANSYS). We first show that the FDTD analysis yields comparable results. Then we use the software to simulate the RSS and TOA of the wideband signals propagated inside the human body for RF localization to compare the accuracies of the two methods. The accuracy of each technique is compared with the Cramer-Rao Lower Bound (CRLB) commonly used for calculation of bounds for the performance of localization techniques and the effects of human body movements.

Experimental meningitis was induced in pigmented guinea pigs by subarachnoid inoculation of \(1 \times 10^9\) Escherichia coli K-12 or \(3 \times 10^7\) CFU Streptococcus pneumoniae serotype 2 D39 (NCTC 7466) or PLN-A, \(\Delta\)NA1 or \(\Delta\)HY1, defined isogenic derivatives of D39 deficient in pneumolysin, neuraminidase or hyaluronidase respectively. All animals developed a meningeal inflammatory response and a labyrinthitis. Hearing loss in pneumococcal meningitis was measured by recording the evoked auditory nerve compound action potential from the round window membrane. Animals infected with PLN-A sustained significantly less hearing loss than those infected with wild-type D39 (12 dB vs. 50 dB 12 h post inoculation; P<0.0001), Neuraminidase deficiency did not alter the course of the meningeal inflammatory response nor affect hearing loss. The \(\Delta\)HY1 mutant survived poorly in the cerebrospinal fluid and blood but still caused hearing loss. Both pneumococcal and E. coli meningitis induced specific ultrastructural lesions in the organ of Corti as judged by high-resolution scanning and transmission electron microscopy, and these lesions were most severe with pneumolysin-sufficient pneumococcal infection. Microperfusion of \(5\times10^6\) CFU S.pneumoniae D39 directly into the scala tympani of guinea pigs also resulted in electrophysiological and ultrastructural damage to the organ of Corti that could be diminished by pretreatment with antibiotics. The data confirm the cochlea as the site of meningogenic deafness. They suggest that pneumolysin expression is chiefly responsible for meningogenic deafness and that if pneumococci invade the inner ear during bacterial meningitis, cochlear deafhess will rapidly ensue.

The vestibular system provides vital information about head position and motion; which is used for the control of balance through vestibulospinal reflexes. Chapter 2 explores the process of transforming head position to body coordinates, with and without vision. The results show when vision is available, the evoked response is less precise. Chapter 3 explores the transformation process before and after 60 days of bedrest. After this period of inactivity, participants swayed more, and their EVS-evoked sway response was less precise. This decrement in precision appears to begin recovery 6 days postbedrest. Chapter 4 focuses on vestibulo-ocular reflexes rather than postural reflexes. Electrical vestibular stimulation is used to evoke measurable torsional eye-movements. The magnitude of the response is modulated by stimulus frequency. Results suggest that CNS interprets electrical vestibular stimulation as a velocity signal rather than a position or acceleration signal. This technique is an ideal measure of pure vestibular function, Chapter 5 utilised the technique in a clinical environment. Vestibular schwannoma patients, with known unilateral vestibular deficit, were tested to identify if the proposed technique can detect this deficit. Results showed that asymmetries could be detected, and, the test may be more sensitive than previously used measures of vestibular asymmetries.

É apresentado um amplificador de potência (PA) com controle digital da potência de saída, operando na banda S de frequência (2,2 GHz). Este PA utiliza um transformador de entrada para reduzir as flutuações dos sinais de terra. Um estágio de excitação oferece uma impedância apropriada para a fonte de entrada e ganho para o próximo estágio. O estágio de controle é usado para melhorar a eficiência do PA, composto por quatro ramos paralelos de chaves, onde os estados (ligado ou desligado) são separadamente ativados por uma palavra de controle de 4 bits. O estágio de saída implementa um amplificador classe E, usando uma topologia cascode para minimizar o estresse de tensão sobre os transistores, permitindo sua utilização sob tensão de alimentação de 3,3 V para se atingir uma potência de saída máxima em torno de 1 W, em um processo CMOS 130 nm, cuja tensão típica de alimentação é 1,2 V. O PA proposto foi projetado em uma tecnologia CMOS 130 nm para RF, ocupa uma área de 1,900 x 0,875 mm2 e os resultados das simulações em leiaute extraído obtidos demonstram uma potência de saída máxima de 28,5 dBm (707 mW), com PAE (Power- Added Efficiency) correspondente de 49,7%, para uma tensão de alimentação de 3,3 V. O controle de 4 bits permite um ajuste dentro da faixa dinâmica da potência de saída entre 13,6 a 28,5 dBm (22,9 a 707 mW), divididos em 15 passos, com o PAE variando de 9,1% a 49,7%. O PA proposto permite redução do consumo de potência quando este não está transmitindo na potência máxima. A potência consumida atinge um mínimo de 0,21Wquando a potência de saída é de 13,6 dBm (22,9 mW) e um máximo de 1,4 W quando a potência de saída é de 28,5 dBm (707 mW), o que representa 1,19 W de economia, aumentando a vida da bateria. A linearidade obtida neste circuito mostrou-se suficiente para atender os requisitos da máscara de emissão de espúrios de um padrão de comunicação com envoltória constante largamente utilizado, apresentando desempenho adequado para atender as especificações dos sistemas de comunicações modernos. / A power amplifier with digital power control useful to S-Band (2.2 GHz) applications and with an output power around 1 W is presented. It uses an input transformer to reduce ground bounce effects. A tuned driver stage provides impedance matching to the input signal source and proper gain to the next stage. A control stage is used for efficiency improvement, composed by four parallel branches where the state (on or off) is separately activated by a 4-bit input. The class-E power stage uses a cascode topology to minimize the voltage stress over the power transistors, allowing higher supply voltages. The PA was designed in a 130 nm RF CMOS process and the layout has a total area of 1.900 x 0.875 mm2, post-layout simulations resulted a peak output power of 28.5 dBm with a maximum power added efficiency (PAE) around 49.7% under 3.3 V of supply voltage. The 4-bit control allows a total output power dynamic range adjustment of 14.9 dB, divided in 15 steps, with the PAE changing from 9.1% to 49.7%. The proposed PA allows reduce the power consumption when it isn’t transmitting at the maximum output power. Where the power consumption is only 0.21 W when the PA is at the minimum output power level of 13.6 dBm (22.9 mW), which is 1.19 W smaller than the power consumption at full mode (1.4 W), increasing the battery life. The linearity in this circuit meet the emission mask requirements for a widely used communication standard with constant envelope. Post-layout simulation results indicate an overall performance adequate to fulfill the specifications of modern wireless communication systems.

Le secteur de communications sécurisés et portables connait une véritable révolution avec l’apparition des plateformes dites radios logiciels (Software Defined Radios, SDRs). Les performances exceptionnelles de ces systèmes sont les résultats d’une interaction assez complexe et souvent peu évidente entre le logiciel embarqué, le circuit de traitement numérique et les blocs mixtes analogiques/RF. Cette complexité limite la testabilité du produit fini. La méthodologie de test utilisée actuellement a atteint ses limites dues au cout élevé, le long temps de test et le bas degré de généralisation. De plus, les plateformes SDRs peuvent évoluer sur le terrain et elles vont supporter des standards et des scénarios qui n’ont pas été considérés pendant le la phase de conception. Donc, une stratégie de test sur le terrain (en ligne) n’est plus une caractéristique optionnelle mais une nécessité. Dans ce contexte, le but de notre recherche est d’inventer et développer une méthodologie de test capable de garantir le bon fonctionnement d’une plateforme SDR après la production et pendant sa vie. Notre objectif final est de réduire le coût du test en profitant de la reconfigurabilité de la plateforme. Pour les radios tactiques qui doivent être mises à jour sur le terrain sans équipement spécial, les stratégies Built-In Self-Test (BIST) sont, sans doute, la seule moyenne de garantir la conformité aux spécifications. Dans cette mémoire, nous introduisons une nouvelle architecture de test RF BIST qui utilise la technique de de sous-échantillonnage nonuniform à la sortie de l’émetteur (TX) d’une SDR afin d’évaluer la conformité de la masque spectrale. Notre solution s’appuie sur une implémentation autonome, est modulable et peut être appliquée pour le test sur le terrain avec des modifications minimes. Par rapport aux autres techniques de test analogiques/RF, cet approche ne dépends pas de la architecture du TX, ni d’un modèle ad-hoc, ce qui est idéale pour le test des SDRs. / The advent of increasingly powerful Integrated Circuits (IC) has led to the emergence of the Software Defined Radio (SDR) concept, which brought the sector of secured mobile communications into a new era. The outstanding performance of these systems results from optimal trade-offs among advanced analog/Radio Frequency (RF) circuitry, high-speed reconfigurable digital hardware and sophisticated real-time software. The inherent sophistication of such platforms poses a challenging problem for product testing. Currently deployed industrial test strategies face rising obstacles due to the costlier RF test equipment, longer test time and lack of flexibility. Moreover, an SDR platform is field-upgradeable, which means it will support standards and scenarii not considered during the design phase. Therefore, an in-field test strategy is not anymore 'a nice to have' feature but a mandatory requirement. In this context, our research aims to invent and develop a new test methodology able to guarantee the correct functioning of the SDR platform post-fabrication and over its operational lifetime. The overall aim of our efforts is to reduce post-manufacture test cost of SDR transceivers by leveraging the reconfigurability of the platform.For tactical radio units that must be field-upgradeable without specialized equipment, Built-in Self-Test (BIST) schemes are arguably the only way to ensure continued compliance to specifications. In this study we introduce a novel RF BIST architecture which uses Periodically Nonuniform Sampling (PNS2) of the transmitter (TX) output to evaluate compliance to spectral mask specifications. Our solution supports a stand-alone implementation, is scalable across a wide set of complex specifications and can be easily applied for in-field testing with small added hardware. Compared to existing analog/RF test techniques, this approach is not limited to a given TX architecture and does not rely on an ad-hoc TX model, which makes it ideal for SDR testing.

Cílem práce bylo porovnat úpravy ekonomické oblasti auditu a auditorské profese dvou zemí. Práce je členěna do čtyř kapitol. Nejdříve se věnuje historickému vývoji auditingu v České republice a Ruské federaci včetně přístupu k definicím auditu, dále seznamuje s úpravou auditingu z hlediska legislativních norem, přístupu k auditu účetní závěrky, s auditorskou profesí, auditorskými směrnicemi, etickým kodexem a vybranými fázemi auditorských postupů v porovnání v České republice a v Ruské federaci. Závěr je zpracován ve snaze rekapitulace zjištěných charakteristik posuzované oblasti a uvedení vybraných odlišností.

Superconducting thin films are a possible alternative to bulk niobium for superconducting radio frequency cavity applications. Thin film cavities have produced larger Q0 than bulk niobium at low accelerating voltages [1], are less susceptible to external magnetic fields and therefore require less magnetic shielding than bulk niobium cavities [2] and can benefit from substrates which conduct heat more effectively than bulk niobium [3]. The major drawback for current thin film cavity technology is the large Q slope which is observed above accelerating gradients of 6 7 MV/m. The mechanism for the Q slope is not yet fully understood. Theories have been suggested but are not accepted by everyone within the scientific community [2, 4, 5, 6, 7]. It is assumed that a better understanding of the physical properties of superconducting films is required before the origins of the sharp Q slope can be elucidated. This study has been conducted to better understand the physical properties of superconducting thin films deposited by the magnetron sputtering process. In particular, superconducting niobium films have been deposited by high power impulse magnetron sputtering (HiPIMS) and tested by a wide range of analytical techniques as a function of the substrate temperature and applied bias during deposition. Analytical techniques which have been used include x-ray diffraction crystallography, Rutherford backscattering spectroscopy, scanning electron microscopy, residual resistance ratio, DC magnetometry and RF surface resistance measurements. Results showed that the application of an applied bias during deposition resulted in increased energy of bombarding ions and enhanced rates of surface diffusion and defect annihilation within the microstructure of a growing niobium film. However, large numbers of random complex defects formed once the energy of bombarding ions becomes too large. The systematic approach that was described to investigate the changing morphological and DC superconducting properties of deposited films, as a function of the applied bias, allowed the identification of which process conditions produce the fewest random complex defects. The same systematic investigations could be applied to any HiPIMS deposition facility to provide similar results. An important observation during the study is that the initial substrate conditions have a large influence on the properties of a deposited niobium film. Niobium films deposited onto polycrystalline copper substrate that was pre-annealed at 700 ˚C prior to deposition displayed more stable magnetic flux pinning, larger RRR and an enhanced resistance to the onset of flux penetration, than was observed for films deposited with a wide range of process conditions onto as received copper substrate. Superconductors other than niobium have been successfully deposited by HiPIMS and tested. Niobium titanium nitride thin films displayed a superconducting transition temperature up to 16.7 K, with a normal state resistivity as small as 45±7 μΩcm. The findings suggest that similar niobium titanium nitride thin films could produce smaller RF surface resistance than bulk niobium cavities at 4.2 K.

abstract: The continuing advancement of modulation standards with newer generations of cellular technology, promises ever increasing data rate and bandwidth efficiency. However, these modulation schemes present high peak to average power ratio (PAPR) even after applying crest factor reduction. Being the most power-hungry component in the radio frequency (RF) transmitter, power amplifiers (PA) for infrastructure applications, need to operate efficiently at the presence of these high PAPR signals while maintaining reasonable linearity performance which could be improved by moderate digital pre-distortion (DPD) techniques. This strict requirement of operating efficiently at average power level while being capable of delivering the peak power, made the load modulated PAs such as Doherty PA, Outphasing PA, various Envelope Tracking PAs, Polar transmitters and most recently the load modulated balanced PA, the prime candidates for such application. However, due to its simpler architecture and ability to deliver RF power efficiently with good linearity performance has made Doherty PA (DPA) the most popular solution and has been deployed almost exclusively for wireless infrastructure application all over the world. Although DPAs has been very successful at amplifying the high PAPR signals, most recent advancements in cellular technology has opted for higher PAPR based signals at wider bandwidth. This lead to increased research and development work to innovate advanced Doherty architectures which are more efficient at back-off (BO) power levels compared to traditional DPAs. In this dissertation, three such advanced Doherty architectures and/or techniques are proposed to achieve high efficiency at further BO power level compared to traditional architecture using symmetrical devices for carrier and peaking PAs. Gallium Nitride (GaN) based high-electron-mobility (HEMT) technology has been used to design and fabricate the DPAs to validate the proposed advanced techniques for higher efficiency with good linearity performance at BO power levels. / Dissertation/Thesis / Doctoral Dissertation Electrical Engineering 2018

L'Internet des objets (IoT) est annoncé comme la prochaine grande révolution technologique où des milliards d'appareils s'interconnecteront en utilisant les technologies d’Internet et permettront aux utilisateurs d'interagir avec le monde physique, permettant Smart Home, Smart Cities, tout intelligent. Les réseaux de capteurs sans fil (WSN) sont cruciales pour tourner la vision de l'IoT dans une réalité, mais pour que cela devienne réalité, beaucoup de ces dispositifs doivent être autonomes en énergie. Par conséquent, un défi majeur est de fournir une durée de vie de plusieurs années tout en alimentant les nœuds par batteries ou en utilisant l'énergie récoltée. Bluetooth Low Energy (BLE) a montré une efficacité énergétique et une robustesse supérieures à celles d'autres protocoles WSN bien connus, ce qui fait BLE un candidat solide pour la mise en œuvre dans des scénarios IoT. En outre, BLE est présent dans presque tous les smartphones, ce qui en fait une télécommande universelle omniprésente pour les maisons intelligentes, les bâtiments ou les villes. Néanmoins, l'amélioration de la performance BLE pour les cas typiques d'utilisation de l'IoT, où la durée de vie de la batterie de nombreuses années, est toujours nécessaire.Dans ce travail, nous avons évalué les performances de BLE en termes de latence et de consommation d'énergie sur la base de modèles analytiques afin d'optimiser ses performances et d'obtenir son niveau maximal d'efficacité énergétique sans modification de la spécification en premier lieu. À cette fin, nous avons proposé une classification des scénarios ainsi que des modes de fonctionnement pour chaque scénario. L'efficacité énergétique est atteinte pour chaque mode de fonctionnement en optimisant les paramètres qui sont affectés aux nœuds BLE pendant la phase de découverte du voisin. Cette optimisation des paramètres a été réalisée à partir d'un modèle énergétique extrait de l'état de la technique. Le modèle, à son tour, a été optimisé pour obtenir une latence et une consommation d'énergie quel que soit le comportement des nœuds à différents niveaux: application et communication. Puisqu'un nœud peut être le périphérique central à un niveau, alors qu'il peut être le périphérique à l'autre niveau en même temps, ce qui affecte la performance finale des nœuds.En outre, un nouveau modèle d'estimation de la durée de vie de la batterie a été présenté pour montrer l'impact réel de l'optimisation de la consommation énergétique sur la durée de vie des nœuds, de façon rapide (en termes de temps de simulation) et réaliste (en tenant compte des données empiriques). Les résultats de performance ont été obtenus dans notre simulateur Matlab basé sur le paradigme OOP, à travers l'utilisation de plusieurs cas de test IoT. En outre, le modèle de latence utilisé pour notre étude a été validé expérimentalement ainsi que l'optimisation des paramètres proposée, montrant une grande précision.Après avoir obtenu les meilleures performances possibles de BLE sans modification de la spécification, nous avons évalué les performances du protocole en implémentant le concept de Wake-Up radio (WuR), qui est un récepteur d’ultra-faible consommation et qui est en charge de détecter le canal de communication, en attente d'un signal adressé au nœud, puis réveiller la radio principale. Ainsi, la radio principale, qui consomme beaucoup plus d'énergie, peut rester en mode veille pendant de longues périodes et passer en mode actif uniquement pour la réception de paquets, économisant ainsi une quantité d'énergie considérable. Nous avons démontré que la durée de vie de BLE peut être significativement augmentée en implémentant une WuR et nous proposons une modification du protocole afin de rendre ce protocole compatible avec un mode de fonctionnement qui inclut une WuR. Pour cela, nous avons étudié l'état de l'art de la WuR et évalué la durée de vie des périphériques BLE lorsqu'une WuR sélectionnée est implémentée du côté master. / The Internet of Things (IoT) is announced as the next big technological revolution where billions of devices will interconnect using Internet technologies and let users interact with the physical world, allowing Smart Home, Smart Cities, smart everything. Wireless Sensor Network (WSN) are crucial for turning the vision of IoT into a reality, but for this to come true, many of these devices need to be autonomous in energy. Hence, one major challenge is to provide multi-year lifetime while powered on batteries or using harvested energy. Bluetooth Low Energy (BLE) has shown higher energy efficiency and robustness than other well known WSN protocols, making it a strong candidate for implementation in IoT scenarios. Additionally, BLE is present in almost every smartphone, turning it into perfect ubiquitous remote control for smart homes, buildings or cities. Nevertheless, BLE performance improvement for typical IoT use cases, where battery lifetime should reach many years, is still necessary.In this work we evaluated BLE performance in terms of latency and energy consumption based on analytical models in order to optimize its performance and obtain its maximum level of energy efficiency without modification of the specification in a first place. For this purpose, we proposed a scenarios classification as well as modes of operation for each scenario. Energy efficiency is achieved for each mode of operation by optimizing the parameters that are assigned to the BLE nodes during the neighbor discovery phase. This optimization of the parameters was made based on an energy model extracted from the state of the art. The model, in turn, has been optimized to obtain latency and energy consumption regardless of the behavior of the nodes at different levels: application and communication. Since a node can be the central device at one level, while it can be the peripheral device at the other level at the same time, which affects the final performance of the nodes.In addition, a novel battery lifetime estimation model was presented to show the actual impact that energy consumption optimization have on nodes lifetime in a fast (in terms of simulation time) and realistic way (by taking into account empirical data). Performance results were obtained in our Matlab based simulator based on OOP paradigm, through the use of several IoT test cases. In addition, the latency model used for our investigation was experimentally validated as well as the proposed parameter optimization, showing a high accuracy.After obtaining the best performance possible of BLE without modification of the specification, we evaluated the protocol performance when implementing the concept of Wake-Up radio, which is an ultra low power receiver in charge on sensing the communication channel, waiting for a signal addressed to the node and then wake the main radio up. Thus, the main radio which consumes higher energy, can remain in sleep mode for long periods of time and switch to an active mode only for packet reception, therefore saving considerable amount of energy. We demonstrated that BLE lifetime can be significantly increased by implementing a Wake-Up radio and we propose a modification of the protocol in order to render this protocol compatible with an operating mode which includes a Wake-Up radio. For this, we studied the Wake-Up radio state of the art and evaluated BLE devices lifetime when a selected Wake-Up radio is implemented at the master side.