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Didier-Fèvre, Catherine. "« The place to be ? » Vivre et bouger dans les entre-deux : jeunesse et mobilités dans les espaces périurbains." Thesis, Paris 10, 2015. http://www.theses.fr/2015PA100095/document.
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Cette thèse de doctorat mène une réflexion sur les mobilités juvéniles périurbaines sous l’angle de « l’entre-deux », terme caractérisant à la fois les espaces périurbains et la jeunesse. Comment la jeunesse vit-elle une localisation résidentielle, choisie par les parents, et se déplace-t-elle dans ces espaces peu densément peuplés et faiblement desservis par des transports en commun ? Quel rôle jouent les contextes périurbains dans la construction identitaire des jeunes ? L’étude menée, à partir de trois lycées généraux et technologiques situés dans les franges de l’agglomération parisienne en proie à un mouvement de périurbanisation plus ou moins ancien, a consisté à interroger une population lycéenne périurbaine par le biais de méthodes qualitatives (85 entretiens) et quantitatives (1522 sondés en ligne). Développant un ancrage différencié à l’espace habité dans lequel la maison individuelle tient une place centrale, les jeunes adoptent une multitude de stratégies pour s’émanciper des contextes périurbains. Ils combinent les ressources des entre-deux pour s’affirmer en tant qu’individu, y compris dans le cadre de la socialisation secondaire marquant cet âge. Ils y trouvent ainsi leur bonheur, bien qu’ils cherchent souvent, de manière plus ou moins réaliste ou réalisable, à sortir de ces espaces. Ces bricolages spatiaux les amènent à développer une motilité (Kaufmann, 2002) plus importante que celle des jeunes urbains. En revanche, à l’heure de s’inventer une vie adulte, ce n’est pas tant l’espace périurbain qui apparaît comme un obstacle à leur projet que les ressources sociales, financières ou culturelles de leur famille. Malgré tout, les contextes périurbains, parce qu’ils font territoires, sont des lieux où les jeunes projettent volontiers leur vie future, même si, pour certains, l’attraction urbaine ou de l’étranger est plus forteThe ‘‘space-in-between’’ refers to any specified situation or space characterizing an intermediary and transitional state. This paper aims at exploring the notion of “space-in-between” through the themes of mobility and the youth living in the periurban fringes of the Great Paris. How does the youth live the residential choice of theirs parents and move to those median zone between rural and urban areas where public transit is deficient? What role have the periurban fringes in the building of the youth identity? Across this research, led in three public high schools located in the periurban fringes of the Great Paris, 85 young spoke about their mobilities and 1522 answered a questionnaire. Become oneself ask to move alone, to explore new spaces without parents but with peers, so these young people combine a lot of means to leave these spaces (walking, hitch-hiking, car-sharing, taking school buses for shopping and so on). Developing a specific link with the periurban areas where the home could be perceived as a special place, these young people live happily and do not consider themselves as ‘‘prisoners’’ in their territories. Nevertheless, they try to going out of them: going to parties, meeting other young people in the night clubs, meeting their friends as they want, practising sport and cultural leisures, and moving anywhere without asking their parents to drive them. At the time to become an adult, when they want to follow high education currucula, if they don’t choose the same way that urban and rural students, it seems that financial ressources and capacities to move are central in their choice. Some of them want to live in big cities or in foreign countries but most of them imagine them living the perurban edges where they had grow up. So the periurban fringes seem, as territories, the ‘place to be’!
El « espacio de transición » es una situación o un espacio que se caracteriza por ser intermedio.Aquella idea de intermedio interesa a los geografos en sus investigaciones sobre el espacio periurbano. Este proyecto , como continuidad de un precedente trabajo de investigaciones (Ser joven en el periurbano de SENS. ¿ Qué movilidades para los alumnos del instituto JANOT ? ; Catherine DIDIER-FEVRE, Máster 2 investigaciones, 2011. 229 páginas), intenta explorar la noción de « transición » a través de las movilidades. Si el término periurbano se define por un espacio de transición (noción aparecida con la instalación de la población en una extensión de la zona urbana) entre dos contrapuestos : espacio urbano y espacio rural, el de la juventud responde también a la noción de « espacio de transición ». En efecto, la juventud es la transición entre la desaparición de las claves de la infancia y la construcción de nuevos modelos. Es un tiempo de experiencias.Mientras « el periurbano sigue siendo el espacio de la juventud en una sociedad envejeciéndose : es el único espacio donde encontramos más de 3 jóvenes para con 2 mayores», muy pocas cosas fueron escritas sobre la juventud del periurbano. Aquella idea de las movilidades de la juventud es nueva. Tener en cuenta la edad de los habitantes de un espacio definido es fundamental para entender las relaciones de ellos con su territorio. Hasta ahora sólo los mayores o los niños pequeños preocuparon a los geografos del periurbano. Al investigar sobre los jóvenes del periurbano una se pregunta :¿Qué relaciones viven los jóvenes con el territorio periurbano al vivir una movilidad singular ?
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Bragg, Eric, Kyla Krogseng, and Christiane Schwaller. "Leveraging a More Sustainable Global Agricultural System : Improving Multinational Organizations' Capacities to Procure." Thesis, Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-3135.
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The procurement of agricultural commodities by multinational organizations has been identified as a leverage point for moving the global agricultural system towards sustainability. This study focuses on how multinational organizations can improve their capacities to procure more sustainably grown agriculture commodities. Using the Framework for Strategic Sustainable Development (FSSD) to create a theoretical ‘Ideal Case’ for procurement practices, this study analyzes the key strengths and weaknesses of existing practices surrounding the procurement of agricultural commodities in order to determine how they can improve. Interviews with four multinational corporations, one INGO and several experts in the field showed various weaknesses, including a lack of whole-system perspectives, inadequate definitions of sustainability, and weak strategies and tools to support organizations’ movements towards sustainability. Using these findings, recommendations were created to provide procurers, sourcing managers, supply chain managers, and sustainability managers with the necessary guidance to create conditions enabling the procurement of more sustainably grown agricultural commodities. The recommendations call for multi-stakeholder cooperation, increased use of impact assessments, long-term sustainability goals, and credible certification systems.
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You, Wei. "Exploring multiple-mode vibrations of capacitive micromachined ultrasonic transducers (CMUTs)." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/44222.
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Capacitive Micromachined Ultrasonic Transducers (CMUTs) are considered advantageous over piezoelectric transducers for ultrasound imaging for the high bandwidth, ease of integration with electronics and miniaturization. Research efforts over the past two decades have been focusing on manufacturing and system integration of CMUTs to achieve comparable and better performance than the piezoelectric counterparts, while the uniqueness of the CMUT structure and physics is barely exploited.
This thesis explores the complex behavior of CMUTs from a mode superposition perspective, and demonstrates imaging applications using CMUTs' multi-modal operation. The operation of CMUTs is first analytically modeled as a coupled electro-mechano-acoustical system using plate vibration theory. As the simplest case, the first symmetric and asymmetric modes of vibration can be excited simultaneously via asymmetric electrostatic actuation, resulting in a vibration profile with a shifted center. Finite element modeling (FEM) is used to verify the theoretical calculation, and an equivalent circuit consisting of two sub-circuits for the symmetric and asymmetric vibration modes is built to show the possibility of fast simulation of complex CMUT array behavior. Experimental characterization of fabricated CMUT chips show that asymmetric vibration can be achieved with multi-electrode CMUTs.
Two imaging applications using the multi-modal operation of CMUTs are proposed. The first concept, tiltable transducers, explores the benefits of orienting each transducer element toward the focal point to concentrate the acoustic energy and reduce grating lobes and side lobes. Imaging simulation shows the grating lobes can be reduced by 20dB while the main lobe energy is preserved. FEM simulation demonstrates that CMUTs capable of asymmetric vibration can be a viable candidate as tiltable transducers with careful design of the cell dimension and central frequency.
The second imaging application takes advantage of the ringing response of a CMUT to off-axis acoustic sources to achieve super-resolution imaging with low computational cost. The differential responses across all CMUT cells form a more decorrelated pattern than the regular average responses, which leads to better estimation performance of the proposed super-resolution algorithm.
While only preliminary experimental results for the proposed applications are presented, the multi-modal operation concept shows potential in improving several aspects of ultrasound imaging.
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Zenteno, Torres Jazmin. "Sliding mode control with fault tolerance capacities : application to a rendezvous mission in a circular orbit." Thesis, Bordeaux, 2020. http://www.theses.fr/2020BORD0063.
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De nombreux travaux de recherche ont ´et´e conduits dans le domaine de synthèse de lois de commande par modes glissants. Différentes approches de commande été proposées dans la litérature, telles que l’algorithme Super-Twisting (STA) et sa version récente, l’algorithme généralisé Super-Twisting (GSTA). Les travaux de recherche présentés dans ce mémoire de thèse s’inscriventdans ces méthodes pour résoudre le problème de commande et de commande tolérante aux fautes, pour une mission spatiale. La mission considère une cible passive et un chasseur. L’objectif visé est de synthétiser les lois de contrôle d’attitude et de mouvement relatif, tolérantes aux pannes. Les approches proposées abordent la problématique des modes flexibles des panneaux solaires etdes phénomènes de ballottement du carburant dans les réservoirs.Dans un premier travail, une loi de commande de type STA est proposée dans une configuration dite de backstepping. Dans un second travail, une loi de commande tolérante aux fautes basée sur les modes glissants du second ordre, est proposée. La solution est basée sur l’algorithme GSTA ,placé en boucle externe de compensation de défauts utilisant un estimateur de défauts non linéaire. Le problème de saturation des actionneurs est également abordé et une solution basée sur la géométrie polytopique, est proposée. Les éléments clés de l’approche tolérante aux pannes sont, i) d’une part la solution ne nécessite pas de diagnostiquer les fautes et donc n’utilise pas d’algorithme de détection et de localisation de défauts, et ii), d’autre part, l’approche est basée sur le formalisme duquaternion dual qui permet de tenir compte des effets de couplage attitude/mouvement relatif. Des critères orientés mission, illustrent les résultats obtenus au travers d’une campagne de simulation réalisteIncreasing attention has grown with regards to Sliding Mode Controllers (SMC). In order to reduce the so-called chattering effect, the Super-Twisting Algorithm (STA) has been proposed, recently. In this work, a controller based on the STA in a backstepping setup, is proposed for spacecraft rendezvous in a circular orbit. A key feature is that the chaser is not treated as a point mass, given that the effects of the flexible modes and propellant sloshing phenomena are considered. The results obtained are taken further, given that the guarantee of robustness against perturbations is not enough when it comes to critical systems, through the second ordersliding mode controllers technique. It is shown that the technique enables to solve to problem of fault tolerant control. The solution is based on the Generalized Super-Twisting Algorithm (GSTA) with an anti-windup strategy and a nonlinear observer and the dual quaternion formalism. The main reason of employing a GSTA is because it offers more robustness against state dependentperturbations (sloshing phenomena and flexible modes) than the STA. In addition, with the help of the anti-windup strategy, the control law does not saturate the thrusters, avoiding instablity when faults occur. The proposed solution is evaluated through a simulation campaign in a high-fidelity non-linear simulator, and mission oriented criteria demonstrate its potential
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Abdel-Fattah, E., and H. Sugai. "Electron heating mode transition observed in a very high frequency capacitive discharge." American Institute of Physics, 2003. http://hdl.handle.net/2237/7247.
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Yu, Feng. "Modeling of V2 Control with Composite Capacitors and Average Current Mode Control." Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/33458.
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Various types of current mode control are being used in different applications. Model for current mode control is indispensable for proper system design. Since 1980s, modeling of current mode control has been a hot topic in power electronics field. In current mode control, sub-harmonic oscillation is a common issue, especially for constant frequency current mode control: like peak current mode control, valley current mode control, or average current mode control.
Recently V2 control is becoming more and more popular due to its simple implementation ad super fast transient response. V2 control can also run into sub-harmonic oscillation just as current mode control. Efforts have been devoted to modeling of V2 control.
A common property of different types of current mode control and V2 control is that they are all multi-loop structures and the inner loops are all highly nonlinear. Due to the nonlinearity of the inner loops, modeling of these structures is extremely difficult. Up to now, there are two main problems which havenâ t been solved: 1. modeling of average current mode control; 2. modeling of V2 control with composite capacitors.
This thesis tries to solve these two problems and starts with V2 control. For V2 control with single type of bulk capacitors, an accurate model has been proposed previously. In this thesis, an equivalent circuit model is proposed to get better physical understanding. This method makes use of previous current mode control modeling result and relates V2 control with current mode control.
To model V2 control with composite capacitors, capacitor currents and output voltage time domain waveforms are analyzed. Based on describing function method, transfer function from control to output is derived. The modeling result shows that with more parallel ceramic capacitors, system has smaller stability margin.
For average current mode control, the structure is compared with V2 control. Similarity between the structures of current compensator in average current mode and output capacitor network in V2 control is identified. V2 model is utilized for average current mode control. The modeling derivation process is simplified. For the current compensator in average current mode control, it is not desired to have a high frequency pole from stability point of view.
As a conclusion, a circuit model for V2 control with bulk capacitors is proposed and another two problems are examined: modeling of V2 control with composite capacitors and modeling of average current mode control. It has been demonstrated that there is similarity between these two structures. The modeling results are verified through simulation and experiments.Master of Science
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Breuzet, Michel. "Resonateurs a ondes elastiques de volume en materiaux amorphes." Paris 6, 1988. http://www.theses.fr/1988PA066108.
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Wu, I.-Tsang. "Integrated Electrostatically- and Piezoelectrically-Transduced Contour-Mode MEMS Resonator on Silicon-on-Insulator (SOI) Wafer." Scholar Commons, 2014. https://scholarcommons.usf.edu/etd/5336.
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Due to the recent rapid growth in personal mobile communication devices (smartphones, PDA's, tablets, etc.), the wireless market is always looking for new ways to further miniaturize the RF front-ends while reducing the cost and power consumption. For many years, wireless transceivers and subsystems have been relying on high quality factor (Q) passives (e.g., quartz crystal, ceramics) to implement oscillators, filters, and other key RF front-end circuitry elements. However, these off-chip discrete components occupy large chip area and require power-demanding interfacing circuits. As a result, a great deal of research effort has been devoted to the development of micromechanical resonators that are much more amenable to direct integration with integrated circuit (IC).
Over the past few years, vibrating RF MEMS (Micro-Electrical-Mechanical-System) resonator technology has emerged as a viable solution, most notably, the film bulk acoustic resonator (FBAR) and surface acoustic wave (SAW) resonator, which have already been successfully implemented into commercial products. Undoubtedly, micromechanical resonators such as FBAR's can perform as well as if not better than its bulky conventional counterparts and facilitate the miniaturization and power reduction of conventional RF systems. However, in some cases when multi-frequency functionality on a single-chip is needed, FBAR simply won't deliver.
To address this dilemma, contour-mode MEMS resonators have been developed and regarded as the most viable on-chip high-Q alternative. Unlike FBAR, contour-mode resonators use lateral dimensions to define its resonating frequencies, thus allowing for single-chip multi-frequency functionality. However, there is still room for improvement with respect to lowering the motional resistance of these devices to allow matching to 50 Ω electronics, while retaining low power consumption, small size, and simpler manufacturing process.
This dissertation presents the design, fabrication, characterization and experimental analysis of two types of micro-mechanical resonators. Piezoelectrically- and electrostatically-transduced micromechanical resonators will both be shown. Both types of resonator will be fabricated in the same micro-fabrication run, which makes the comparison between the two much more impartial. The impacts of substrate's resistivity over the device performances will also be studied.
Among the most significant results, this dissertation also presents several ideas that are enabled by the use of silicon-on-insulator (SOI) wafer. A novel single-mask fabrication process that can produce capacitive resonator with nano-meter gap is demonstrated. The concept of dual-transduced micro-mechanical resonator is introduced by combining both piezoelectric and capacitive based resonators. Finally, frequency tuning of MEMS resonator are explored and detailed in this work as well.
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Bord, Isabelle. "Etude d'un capteur capacitif différentiel pour la détection de pluie." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2006. http://tel.archives-ouvertes.fr/tel-00399619.
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Ces travaux portent sur le développement d'un capteur capacitif de pluie à électrodes protégées fonctionnant en mode différentiel. Dans un premier temps, les propriétés électriques des différents matériaux constitutifs du capteur sont déterminées expérimentalement. A partir de considérations théoriques, nous avons établi des expressions semi-empiriques traduisant la dépendance en fréquence [10^2 à 10^5Hz] et en température [−40 à +80°C] des permittivités diélectriques, nécessaires aux calculs des capacités. Le capteur est ensuite dimensionné par simulation numérique (méthode des éléments finis) puis fabriqué selon différents procédés de dépôt pour les électrodes. Deux motifs d'électrodes sont étudiés : électrodes linéaires et électrodes interdigitées. La sensibilité à l'eau est évaluée par simulation numérique (film puis gouttes d'eau de volume variable) avant validation expérimentale. L'influence de la température sur les performances du capteur est finalement abordée : les effets de la dilatation thermique des matériaux et de la variation des permittivités diélectriques sont successivement traités. A l'issue de cette étude, l'efficacité du mode différentiel contre l'influence de la température est évaluée.
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Suciu, Constantin. "Switch mode emulation of large value capacitors in the rotor circuit to improve the induction motor performance." Thesis, Nottingham Trent University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314331.
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Summers, Clinton Thomas. "Distance Protection Aspects of Transmission Lines Equipped with Series Compensation Capacitors." Thesis, Virginia Tech, 1999. http://hdl.handle.net/10919/35284.
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In order to meet the high demand for power transmission capacity, some power companies have installed series capacitors on power transmission lines. This allows the impedance of the line to be lowered, thus yielding increased transmission capability. The series capacitor makes sense because it's simple and could be installed for 15 to 30% of the cost of installing a new line, and it can provide the benefits of increased system stability, reduced system losses, and better voltage regulation.1
Protective distance relays, which make use of impedance measurements in order to determine the presence and location of faults, are "fooled" by installed series capacitance on the line when the presence or absence of the capacitor in the fault circuit is not known a priori. This is because the capacitance cancels or compensates some of the inductance of the line and therefore the relay may perceive a fault to be in its first zone when the fault is actually in the second or third zone of protection. Similarly, first zone faults can be perceived to be reverse faults! Clearly this can cause some costly operating errors.
The general approach of interest is a method leading to the determination of the values of series L and C of the line at the time of the fault. This is done by analyzing the synchronous and subsynchronous content of the V and I signals seperately which provides adequate information to compute the series L and C of the line.Master of Science
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Belkadi, Nesrine. "Nouveaux MEMS C-BAR : résonateurs capacitifs à ondes élastiques de volume piégées sur substrat Silicium." Thesis, Besançon, 2016. http://www.theses.fr/2016BESA2088.
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Ces travaux de thèse décrivent l’étude et la réalisation de résonateurs MEMS (Micro-ElectroMechanical Systems) acoustiques à couplage capacitif dits C-BAR (Capacitive Bulk Acoustic Resonator). Les C-BAR exploitent les modes d’extension-compression d’épaisseur en mode fondamental à 9, 45MHz. L’élément vibrant est constitué de Si-monocristallin purement résistif et d’orientation (100). Notre but consiste à transposer au monde des MEMS a` excitation capacitive les caractéristiques de stabilité des résonateurs piézoélectriques BAW utilisés dans les sources de fréquences embarquées. Notre stratégie de développement s’est fondée sur l’exploitation de deux concepts originaux dans les domaines respectifs électrique et acoustique : l’intérêt immédiat des résonateurs MEMS-Si capacitifs tient à la disponibilité du matériau, au faible coût unitaire, à la produire à grande échelle, ainsi qu’à la robustesse. A plus longue échéance, cet intérêt tient au potentiel d’intégration avec l’électronique de commande ; Cette recherche est motivée par la nécessité d’éliminer les pertes structurelles dans les résonateurs MEMS. Grâce à l’étude de la dispersion acoustique des ondes élastiques guidées dans une plaque de Si, nous avons pu contrôler les bandes d’arrêt par modification locale des caractéristiques de la propagation afin de confiner l’énergie acoustique au centre du résonateur. Une première partie de ces travaux est consacrée à la modélisation du C-BAR. Grâce à des simulations FEM appuyées sur des calculs analytiques, nous avons défini les limites imposées aux paramètres constructifs pour l’obtention de performances satisfaisantes pour les applications visées. Nous avons notamment quantifié le nécessaire compromis entre les quantités antagonistes constituées par le k2, limité par la rigidité statique de la plaque, et le Q, limité par les constantes de dispersion des modes exploités et le facteur d’aspect de la plaque. La deuxième partie est consacrée à la micro-fabrication du C-BAR exploitant les micro techniques disponibles au sein de la Centrale MIMENTOThis PhD work describes the study and realization of capacitive Bulk Acoustic Waves MEMS resonators (C-BAR) exploiting the thicknessextensional vibration modes at 9, 45MHz of a mono-crystalline silicon plate (100). The aim of this research consists in translated to the domain of capacitive MEMS the good performances of BAW resonators for embedded frequency sources. The proposed work proposes new resonant structures bearing some originality from electric and acoustic viewpoints : capacitive full Si-MEMS have some immediate interest in the field of material availability, low cost per item, volume production and robustness, notwithstanding their know ability for electronic integration ; This research was motivated by the need to eliminate structural losses to reach the limits imposed by the material itself. With help of a study of dispersion curves, we managed a control of acoustic confinement by means of a local patterning of the surface of the vibrating element. By a proper mastering of the stop band of guided elastic waves in the structure, we can overcome the intrinsic limitations of structural MEMS. The first lock of this work is dedicated to the modeling of the C-BARs. It uses a combination of analytic and FEA calculations to frame the actual design of the resonators. This permits us to determine the limits imposed to the performances of such structures. This part especially points out the contradictory requirements of the C-BARs in terms of electromechanical coupling factor and of surtension coefficient. The second lock describes the issues of the micro-fabrication of the C-BARs at MIMENTO clean room facility
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Mourad, Hussein. "Mise en œuvre d’une méthodologie pour l’étude de rayonnement parasite basse fréquence de panneaux solaires sur des capteurs situés en zone proche." Limoges, 2007. https://aurore.unilim.fr/theses/nxfile/default/60bd8d91-54c9-4c60-a501-e14879bb1cd2/blobholder:0/2007LIMO4011.pdf.
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DEMETER (Detection of Electro-Magnetic Emissions Transmitted from Earthquakes Regions) est le premier microsatellite développé par le CNES (Centre National d’Etudes Spatiales). Son objectif est d’étudier les perturbations de l’ionosphère associées à l’activité sismique ou volcanique. Le satellite possède des sondes très sensibles qui ont pour rôle de mesurer les fluctuations du champ magnétique terrestre. Pour un fonctionnement normal du satellite, il est important que le bruit électromagnétique généré par la structure elle-même et en particulier par les panneaux solaires soit suffisamment faible pour ne pas perturber les mesures des sondes. Les travaux présentés dans cette thèse s’inscrivent dans la contribution à l’étude du rayonnement parasite basse fréquence de panneaux solaires en champ proche. L’analyse topologique de la distribution des courants de mode commun et de mode différentiel à travers les différents chemins de câblage des cellules solaires permet la construction d’un réseau de dipôles électriques équivalents du système et le calcul du champ électromagnétique rayonné en un point donné de son environnement par sommation vectorielle de toutes les contributions dipolairesDEMETER (Detection of Electro-Magnetic Emissions Transmitted from Earthquakes Regions) is the first microsatellite developed by the CNES (Centre National d’Etudes Spatiales). Its objective is to study the disturbances of the ionosphere associated with the seismic or volcanic activities. The satellite has very sensitive probes which have to measure the fluctuations of the terrestrial magnetic field. For a normal operation of the satellite, it is important that the electromagnetic noise generated by the structure itself and in particular by the solar panels is sufficiently weak not to disturb measurements of the probes. The work presented in this thesis falls under the contribution to the study of low frequency parasitic radiations of solar panels in the near field. The topological analysis of the distribution of the currents of common mode and differential mode through the various ways of wiring of the solar cells allows the construction of a network of equivalent electric dipoles of the system and the calculation of the electromagnetic field radiated in a given point of its environment by vectorial summation of all dipolar contributions
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Vakili-Amini, Babak. "A Mixed-Signal Low-Noise Sigma-Delta Interface IC for Integrated Sub-Micro-Gravity Capacitive SOI Accelerometers." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/10437.
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This dissertation presents the design and development of a mixed-signal low noise second-order integrated circuit (IC) for the open-loop and closed-loop operation of integrated capacitive micro- and nano-gravity accelerometers. The micromechanical accelerometers are fabricated in thick (less than 100 m) silicon-on-insulator (SOI) substrates. The IC provides the 1-bit digital output stream and has the versatility of interfacing sensors with different sensitivities while maintaining minimum power consumption (less than 5 mW) and maximum dynamic range (90 dB). A fully-differential sampled-data scheme is deployed with the ability of low-frequency noise reduction through the use of correlated double sampling (CDS) scheme. In this work, the measured resolution of the closed-loop CMOS-SOI accelerometer system, in the presence of high background accelerations, is in the micro-g (g: gravity) range. In this design, a second-order SC modulator is cascaded with the accelerometer and the front-end amplifier. The accelerometer operates in air and is designed for non-peaking response with a BW-3dB of 500 Hz. A 22 dB improvement in noise and hence dynamic range is achieved with a sampling clock of 40 kHz corresponding to a low oversampling ratio (OSR) of 40. The interface IC consumed a current of 1.5 mA from a supply of 3 V.
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Toure, Baïdy Birame. "Modélisation haute-fréquence des variateurs de vitesse pour aéronefs : contribution au dimensionnement et à l'optimisation de filtres CEM." Thesis, Grenoble, 2012. http://www.theses.fr/2012GRENT038/document.
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Depuis une bonne dizaine d'année, l'aéronautique a entamé sa mutation vers le "plus électrique".L'objectif étant de réduire la consommation de carburant, une des contraintes majeures de ces nouvelles solutions est de réduire la masse embarquée. Les filtres dimensionnés pour les convertisseurs statiques doivent donc être optimisés au mieux vis-à-vis de ce critère, ainsi que du volume. Il y a donc un fort besoin du côté des concepteurs d’avions de savoir quels choix parmi les différentes possibilités technologiques sont optimaux, et de connaître l'impact de ces choix sur le poids, le coût global et le volume de l'équipement. Le filtre CEM représente généralement environ 30% du coût et du volume d'un convertisseur électronique de puissance. Il va de soi que le volume et/ou la masse de ces filtres doit être optimisé. L'impact de la loi de commande du convertisseur, le choix des semi-conducteurs, du packaging, câbles (longueur et intégration dans l’avion), des machines électriques,...doivent être parfaitement connus pour atteindre un dimensionnement optimal.Dans cette perspective, les objectifs de ces travaux de thèse visent à fournir non seulement une démarche méthodologique pour la modélisation haute fréquence des variateurs de vitesse dédiés aux applications aéronautiques mais aussi une approche de dimensionnement par optimisation des filtres CEM. Pour cela, un outil logiciel évolutif d’aide à la génération rapide des modèles CEM est proposé. Une description modulaire et une mise en équation automatique du modèle fréquentiel complet ainsi que des gradients en facilitent l'utilisation en procédures d’optimisation sous contraintes. L’approche présentée dans ces travaux est relativement générique : la topologie du filtre, de la structure du convertisseur, du câblage et la loi de commande peuvent être facilement recalculées, grâce à cet environnement logicielThe More Electrical Aircraft concept is very promising regarding energy saves, but generates new problems, and especially the emergence of new power electronics loads on the electrical network. Keeping the same level of safety in the aircraft means developing these switching mode converters in accordance with the aircraft standards, as the DO160. This is not obvious since weights of equipments are especially constrained: indeed, the objective of weight and energy save needs to be balanced with the additional weight and volume of the required EMI filters. There is thus a strong need in helping the aircraft designers to choose among the various technological possibilities, and to know the impact of these choices on the global weight, cost and volume of the embedded equipments. The EMI filter usually represents roughly 30% of the cost and volume of a power electronics converter, and it is very important to optimize it. The impact of the converter control law, semiconductors choice, interconnects realization, harness selection and placement, electrical motors characteristics… should be perfectly known in order to reach a good system design. In this perspective, the objectives of this thesis are to provide not only an approach for modelling high frequency variable speed drives dedicated to aerospace applications but also a methodology to optimize the required EMI filters. For this purpose, new architecture software dedicated to the rapid generation of EMC models is proposed. A modular description and a complete automatic model generation facilitate the use by the designer in optimization procedures thanks to automatic gradient computation.The methodology presented in this work is not specifically developed for a given application. It is a very generic approach: the topology of the filter, the structure of the inverters, interconnects and the control law can be easily recalculated, using this software environment. Consequently, the impact of all these elements on the electromagnetic disturbances can be characterized, and the EMI filter optimized
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Zaid, Bilel. "Méthode d’optimisation du volume des bobines de mode commun pour la conception des filtres CEM." Thesis, Lille 1, 2018. http://www.theses.fr/2018LIL1I065/document.
Full textAbstract:
Ce travail de thèse présente une méthode d'optimisation du volume de la bobine de mode commun qui est généralement l'élément le plus volumineux du filtre. Le manuscrit commence par faire l'état de l'art des perturbations électromagnétiques conduites en électronique de puissance et des moyens permettant leur réduction. Ensuite, un calcul analytique de l'inductance de mode commun minimale qui permet de respecter la norme CEM est présenté. Ce calcul prend en considération la perméabilité complexe du matériau magnétique et les impédances des chemins de propagation des perturbations de mode commun dans la chaîne. Une fois l'inductance minimale calculée, une méthode d'optimisation du volume de la bobine de mode commun monocouche qui tient compte de la saturation du matériau magnétique est présentée. L'application de la méthode proposée dans diverses situations a montré l'existence d'une meilleure inductance, pouvant être supérieure à sa valeur minimale, qui permet de réduire au mieux le volume de la bobine. Par ailleurs, des règles de dimensionnement en relation avec la fréquence de commutation du convertisseur et de son rapport cyclique sont définies. La dernière partie de cette étude est dédiée à la prise en compte des effets de la capacité parasite équivalente de la bobine dans la procédure de dimensionnement. D'abord, une méthode pour la détermination des permittivités relatives du noyau magnétique et pour l'estimation de la capacité parasite équivalente est proposée. Cette méthode, accompagnée d'un calcul de la capacité maximale autorisée, permet d'adapter la géométrie de la bobine afin de respecter la contrainte normative en HF tout en optimisant son volumeThis work presents an optimization method of the common mode inductor volume that is generally the biggest element of the filter. The manuscript starts by presenting the state of art of conducted electromagnetic interferences in power electronics and techniques that allow their reduction. Then, an analytical calculation method of the minimal inductance value that allows respecting the normative constraint is presented. This calculation method takes into account the complex permeability of the magnetic material and the impedances of the different propagation path of common mode disturbances in the conversion system. After that, an optimization method of the single layer inductor volume with considering the magnetic core saturation issues is proposed. The application of the proposed method in different situations has shown the existence of the best inductance value that can be higher than its minimal value while reducing the optimal inductor volume. In addition, some rules that can be used in the design process in relation to the switching frequency of the converter and its duty cycle are defined. In the last part of this study, the effect of the equivalent parasitic capacitance of the common mode inductor is discussed and introduced in the proposed optimization process. A determination method of magnetic core relative permittivities and of the equivalent parasitic capacitance is proposed. This method, in addition to the proposed analytical calculation of the maximal allowed parasitic capacitance, makes it possible to adapt common mode inductor geometry in order to respect the normative constraint in the high frequencies while optimizing its volume
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Majjad, Hicham. "ÉTUDE ET RÉALISATION DE MICRORÉSONATEURS EN TECHNIQUE LIGA-UV." Phd thesis, Université de Franche-Comté, 2001. http://tel.archives-ouvertes.fr/tel-00009998.
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Cette étude a pour but la conception de microrésonateurs basses fréquences réalisés par une technique de microfabrication collective : la LIGA-UV. Il est donc nécessaire dans un premier temps de connaître les propriétés mécaniques du matériau choisi pour la réalisation, à savoir le nickel obtenu par électroformage. On détermine donc le module de Young ainsi que l'amortissement interne du matériau grâce au plus simple des microrésonateurs à savoir une micropoutre encastrée-libre. La démarche suivie lors de la phase de conception de ces microrésonateurs est la suivante : tout d'abord développer un modèle analytique qui permet de déterminer le maximum de paramètres géométriques. Ensuite, l'utilisation d'un modèle éléments finis, qui prend en compte plus de paramètres, permet d'affiner la géométrie grâce à des conditions aux limites proches de la réalité et de simuler le fonctionnement du microsystème. Ainsi, cette démarche a été suivie par la réalisation et la caractérisation de microrésonateurs en nickel à mode de flexion dans le plan qui vibrent à 70 kHz. L'excitation et la détection se font par le biais de peignes interdigités. Les fréquences expérimentales sont confrontées aux résultats des simulations avec une corrélation très satisfaisante. Enfin, un prototype de microrésonateur qui vibre à 6 MHz et dont l'originalité réside dans son mode de contour ou mode de Lamé a été réalisé. La vibration qui a lieu dans le plan a ses nœuds aux quatre coins et au centre de la plaque. L'excitation du microrésonateur se fait de manière électrostatique, quant à la détection elle se fait par l'intermédiaire d'un interféromètre laser hétérodyne. Les résultats ont montré un coefficient de qualité Q d'environ 1200 à l'air. Ce type de microrésonateur est le candidat idéal pour la réalisation d'un oscillateur intégré sous vide qui entraînerait une nette amélioration de ses performances mécaniques.
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Tan, Wenhua. "Modélisation et Conception des Composants Passifs Planar pour Filtres CEM." Phd thesis, Ecole Centrale de Lille, 2012. http://tel.archives-ouvertes.fr/tel-00776515.
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Les composants magnétiques en technologie planar répondent aux exigences actuelles de l'Electronique de Puissance (EP), à savoir la montée en fréquence de commutation des structures d'EP et la réduction du volume des convertisseurs. La première tendance impose des contraintes fortes en termes de compatibilité électromagnétique (CEM) des équipements. Ces dernières doivent être prises en compte par les ingénieurs dès la phase conception des convertisseurs en se basant sur des modèles fiables, peu développés pour les composants planar dans la littérature scientifique. Ce travail de thèse porte ainsi sur la modélisation des composants planar pour applications aux filtres CEM. Différentes méthodes sont développées au cours de cette thèse pour arriver à évaluer de manière fine les éléments parasites des inductances planar de mode commun : capacités parasites et inductances de fuite. Une partie du travail a porté sur la modélisation par circuits équivalents du comportement fréquentiel des inductances de MC. Une approche automatisée, basée sur un algorithme de fitting a ainsi été développée pour élaborer des circuits équivalents fiables et robustes. Des approches analytiques (Décomposition du Champ Electrique) et semi-analytiques (Fonctions de Green) ont aussi été proposées pour évaluer les valeurs des éléments parasites. La dernière partie de la thèse est plus orientée conception, avec la réalisation de deux structures de composants innovantes, la première se basant sur une technique de compensation des capacités parasites à l'aide d'éléments parasites structuraux et la seconde sur l'association de deux noyaux magnétiques, possédant matériaux et géométries différentes
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Diagne, Birahim. "Étude et modélisation compacte d'un transistor MOS SOI double-grille dédié à la conception." Phd thesis, Université Louis Pasteur - Strasbourg I, 2007. http://tel.archives-ouvertes.fr/tel-00206167.
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Nous proposons un modèle compact du transistor MOS double-grille silicium sur isolant (SOI) en mode de fonctionnement symétrique. Le modèle est basé sur le formalisme EKV et offre les caractéristiques suivantes : une expression analytique simple décrivant le comportement statique et dynamique du dispositif, des relations « directes » entre charges–tensions et tensions–courant, une méthode de calcul numérique robuste et rapide, une implémentation aisée du modèle dans un langage de haut niveau tel que VHDL-AMS permettant ainsi une simulation rapide et précise des caractéristiques électriques.Le modèle prend en compte non seulement les effets de petites géométries tels que l'abaissement de la barrière de potentiel induit par le drain, le partage de charge, la dégradation de la pente sous le seuil ainsi que la réduction de la mobilité des porteurs, mais également les effets dynamiques extrinsèques.
Il a été validé pour des dispositifs de longueur de canal de 60nm. Sa validation a été effectuée par comparaison de ses résultats avec ceux obtenus sur le simulateur de composants Atlas/SILVACO.
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Di, Molfetta Sabino. "Studio del modello di vita e di affidabilità di condensatori "Brick" in film per applicazione Automotive per macchine elettriche o ibride." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019.
Find full textAbstract:
Il mio progetto di tesi dal titolo "Studio del modello di vita e di affidabilità di condensatori "Brick" in film per applicazioni Automotive per macchine elettriche o ibride, è stato svolto in collaborazione con un'azienda di prodotto, leader mondiale nella progettazione e produzione di condensatori. L'obiettivo del mio progetto è stato quello di studiare, da un punto di vista affidabilistico, i modelli di vita dei condensatori in film di polipropilene utilizzati per applicazioni automotive. I test analizzati consistono nel sottoporre il dispositivo a determinati stress di temperatura e tensione, dalla durata variabile di tn ore, in modo tale da valutare l'affidabilità e la vita attesa garantita dal condensatore. Le attività svolte possono essere suddivise in tre grandi blocchi: organizzazione dei dati, andando a considerare un unico "failure mode", "Fitting" dei dati tramite il modello considerato ed infine costruzione del Test Plan in modo da soddisfare le seguenti richieste aziendali: determinazione della durata di ciascuno stress, determinazione del numero di campioni per ogni livello di stress e determinazione dei livelli di stress.
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Mayberry, Curtis Lee. "Interface circuits for readout and control of a micro-hemispherical resonating gyroscope." Thesis, Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53116.
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Gyroscopes are inertial sensors that measure the rate or angle of rotation. One of the most promising technologies for reaching a high-performance MEMS gyroscope has been development of the micro-hemispherical shell resonator. (μHSR) This thesis presents the electronic control and read-out interface that has been developed to turn the μHSR into a fully functional micro-hemispherical resonating gyroscope (μHRG) capable of measuring the rate of rotation. First, the μHSR was characterized, which both enabled the design of the interface and led to new insights into the linearity and feed-through characteristics of the μHSR. Then a detailed analysis of the rate mode interface including calculations and simulations was performed. This interface was then implemented on custom printed circuit boards for both the analog front-end and analog back-end, along with a custom on-board vacuum chamber and chassis to house the μHSR and interface electronics. Finally the performance of the rate mode gyroscope interface was characterized, showing a linear scale factor of 8.57 mv/deg/s, an angle random walk (ARW) of 34 deg/sqrt(hr) and a bias instability of 330 deg/hr.
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Guedj, Annie. "Oxydation photo-assistee du silicium par laser au co2 continu et contribution a l'etude des couches de silice obtenues." Toulouse, INSA, 1987. http://www.theses.fr/1987ISAT0011.
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Les caracteristiques de "l'oxyde laser" obtenu sont etudiees: 1)grace au controle de temperature par pyrometrie en ce qui concerne la cinetique de croissance. 2) a partir de mesures c(v) et i(v) en ce qui concerne les proprietes electriques. 3) par spectrometrie ir en ce qui concerne les proprietes physiques. Ces caracteristiques sont ensuite comparees a celles de l'oxyde thermique conventionnel. Enfin, par la realisation de transistors m. O. S. A "oxyde laser" (oxyde de grille), nous avons montre que ce mode d'oxydation assistee par laser peut etre utilise dans les technologies m. O. S.
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Sutorý, Tomáš. "NOVÉ PRINCIPY CHARAKTERIZACE HRADLOVÝCH KAPACIT PRO SIGMA-DELTA MODULÁTORY." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-233499.
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This thesis deals with the utilization of new principles of characterization of gate capacitances for sigma-delta modulators. Sigma-delta modulators are the integral part of sigma-delta analog-to-digital converters. The proposed new method is characterized by high resolution and modest requirements for laboratory equipment. It allows characterizing capacitances whose values are within the range which is used in sigma-delta modulators. The thesis contains description of the new method, the analysis of measurement accuracy and experimental results.
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Yang, Wen-Fu, and 楊文富. "Design of Sweeping Mode Capacitive Fingerprint Sensor Chip." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/79920172585469286937.
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碩士國立暨南國際大學
電機工程學系
94
Abstract Capacitive fingerprint sensing scheme can not only prevent the counterfeit of fingerprint image but also can be easily integrated with associated readout circuits to realize a single-chip fingerprint identification system. For the economic issue of portable applications, sweeping mode of capacitive fingerprint sensing is adopted, to save the chip size and cost. In this thesis, a sweeping mode capacitive fingerprint sensor and readout chip is designed and implemented by using standard CMOS process. The capacitive sensor acquires the fingerprint image by detecting the capacitance induced by human fingerprint. The chip employs pixel-wise design, where the readout circuit and sensing capacitor are integrated in each pixel to acquire accurate sensing value, for two-dimensional array readout. The sensed analog value of each pixel is then selected and transformed to digital value by an on-chip ADC. A chip containing 8128 sensors array and peripheral control circuit is implemented by using TSMC 0.35-m 2P4M CMOS process provided by Chip Implementation Center. The chip works at single 5V power supply and 500kHz clock. Capacitance value ranging from 0fF to 60fF can be sensed with corresponding output voltage ranging is from 0.7V to 2.64V. The digital output is 4bits. The chip consumes power 18mW.
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Yang, Tsung-Jung, and 楊宗融. "Time-mode Sigma-Delta Interface Circuit for Capacitive Sensors." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/32565526368162638761.
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碩士國立臺灣大學
電子工程學研究所
102
This thesis illustrates the design and implementation of interface circuits for capacitive sensors. The interface circuits perform femto farad resolution at typical sampling rate, which is designed for measuring the change of capacitance under physical change. With linear corresponding relationship between capacitance and output digital code, the interpolation is available in capacitance calculation. By using a standard TSMC 0.18-μm CMOS process, there are two circuits implemented and the functions are verified in measurement results. Firstly, time-mode approach is introduced to provide a solution suitable for process migration. A sigma-delta modulator is employed to achieve high resolution and the relationship between input and output digital code is linear. The proposed sensor interface is simply composed of a charge pump and a time-mode sigma-delta modulator to reduce the need for traditional analog building blocks as much as possible. Secondly, the multi-bit architecture and additional power-saving techniques are applied to maintain overall performance while reducing the power consumption by half. With the digital output generated form the fabricated chip, the raw data can be easily collected with a logic analyzer and then processed directly with MATLAB on a computer. The chip areas are both 0.68*0.68 mm2. Operated at a 1.2-V supply voltage, the fabricated circuits consume average power of 817 μW and 360 μW and achieve an effective number of bits (ENOB) of 8.8 and 9.07 and figure-of-merit (FoM) of 114.5 pJ/step and 41.7 pJ/step, respectively.
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Chung, Wei-Cheng, and 鍾威正. "Development of CMOS-based Capacitive Micromachined Ultrasonic Transducers Operated in Collapse-mode." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/00860602134244627574.
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碩士國立臺灣大學
電子工程學研究所
102
In this work, experimental results of Capacitive Micromachined Ultrasonic Transducers (CMUTs) operated in collapse-mode is presented. The device is implemented with the TSMC 0.35μm CMOS-MEMS process. Through the surface profile measured by a confocal microscope, the collapsed voltage is measured at approximately 50 ~ 60V. With a bias voltage over the collapse voltage, the receiving sensitivity of CMUTs is increased 4 times larger and the center frequency is shifted from 2.7MHz to 7.9MHz. Driven by a commercial pulser, the received echo signal using our device in traditional mode is 2.625Vpp and the fractional bandwidth is 132%. Affected by the deep-collapse operation, the largest received echo signal reaches 3.427Vpp and the fractional bandwidth reduced to approximately 40 ~ 45%. The CMUT center frequency shifts from 3.12MHz to 9.12MHz. We also present an improved wet etch process to significantly increase the yield to almost 100%. Depositing thicker sealing membrane material ensures the robustness of CMUTs. Our developed CMUTs operated in DC bias of 90V in a water tank for over half an hour was demonstrated.
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Wu, Jian-Yu, and 吳建宇. "Voltage/Current-Mode Multi-Function Filters Using Current-Feedback Amplifiers and Grounded Capacitors." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/09138404727376183473.
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碩士中原大學
電子工程研究所
99
One configuration for realizing voltage-mode multi-function filters and another configuration for realizing current-mode multi-function filters each using two current-feedback amplifiers (CFAs) are presented. The proposed voltage-mode circuit exhibits simultaneously lowpass, bandpass and highpass filters. The proposed current-mode circuit also exhibits simultaneously lowpass, bandpass and highpass filters. The proposed circuits offer the following features: no requirements for component matching conditions; low active and passive sensitivities; employing only grounded capacitors and the ability to obtain multi-function filters from the same circuit configuration.
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Huang, Wei-Hsiang, and 黃偉祥. "Voltage/Current-Mode Multifunction Filters Using One Current Feedback Amplifier and Grounded Capacitors." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/41552750684685856083.
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碩士中原大學
電子工程研究所
100
Abstract One configuration for realizing voltage-mode multifunction filters and another configuration for realizing current-mode multifunction filters using current feedback amplifiers (CFAs) are presented . The proposed voltage-mode circuit exhibit simultaneously lowpass and bandpass fiters. The proposed current-mode circuit exhibit simultaneously lowpass, bandpass and highpass filters. The proposed circuit offer the following features: No requirements for component matching conditions; low active and passive sensitivities; employing only grounded capacitors and the ability to obtain multifunction filters from the same circuit configuration.
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Cheng, Ta-Yang, and 鄭達陽. "FlickBoard: Enabling Trackpad Interaction with Automatic Mode Switching on a Capacitive-sensing Keyboard." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/29870770603158177441.
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碩士國立臺灣大學
資訊工程學研究所
103
We present FlickBoard, which combines a touchpad and a keyboard into the same interaction area to reduce hand movement between separate key- boards and touchpads. It supports automatic input mode detection and switch- ing (ie. touchpad vs keyboard mode) without explicit user input. We devel- oped a prototype by embedding a 58x20 capacitive sensing grid into a soft keyboard cover, and uses machine learning to distinguish between moving a cursor (touchpad mode) and entering text (keyboard mode). We conducted experimental studies that show automatic mode switching classification ac- curacies of 98% are achievable with our technology. Finally, our prototype has a thin profile and can be placed over existing keyboards.
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MA, SIAN-CING, and 馬憲慶. "Voltage-Mode Fourth-Order Elliptic Filter with OTRAs,Resistors(or MOS FETs),and Capacitors." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/33487629174408634379.
Full textAbstract:
碩士中原大學
電機工程研究所
98
This brief presents a voltage-mode fourth-order elliptic filter, and reduces the parasitic effect to obtain accurate output signal as the goal, so we offer the Analytical Synthesis Method (ASM), using fourth-order elliptic transfer function to design the circuit, because it can reduce voltage node numbers, so the parasitic effects can be reduced. We offer the special component - Operational Trans-Resistance Amplifier (OTRA),because its input node is virtual ground, so it can reduce parasitic effects ,too. So far, this component is the only one have the excellent characteristic. The circuit of this paper, since it offer ASM and OTRA to design circuit, hence it can reduce parasitic effect to achieve the design goal. The simulation of this paper uses H-Spice with TSMC035 process to obtain the results. From the simulation result and using Matlab to testify the theoretical predictions, we can observe the difference between theoretical parts and simulation parts. The simulation result have fourth-order elliptic filter characteristic, we can use sensitivity to tunning the component value,let the output become more accurate. Finally, we will use MOS to replace the resistance because the MOS is more easy to exact in IC fabrication.
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Yeh, Cheng-Yen, and 葉政彥. "Compensation of Parasitic Inductance for Capacitors Applied to Common- and Differential-Mode Noise Suppression." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/jps5mn.
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碩士國立中山大學
電機工程學系研究所
95
The suitable frequency range of electromagnetic interference (EMI) filters is always limited by the parasitic inductances and capacitances of components. The main object in this research is to develop design rules for lowering parasitic effects due to parasitic inductance of capacitor by using three coupled inductors. In this thesis, the properties and equivalent circuit of three coupled inductors are discussed first. It is found that two negative series inductances can be simultaneously obtained at two ports when the parameters of three coupled inductors are appropriately selected. These two negative inductances can be used to lower parasitic effect of capacitors. In other words, the EMI filter performance can be effectively improved by using this technology. Furthermore, method to completely reduce parasitic inductances is derived. The common mode insertion loss of this design is able to achieve at the rate of -60 dB/decade at high-frequency. For differential mode the insertion loss is even higher to the rate of -100 dB/decade.
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Su, Chung-Da, and 蘇俊達. "Design of universal voltage-mode biquadratic filters with OTRAs, Resistors(or MOS transistors) and capacitors." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/96763677458084807777.
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碩士中原大學
電機工程研究所
98
Recent years, operational transresistance amplifier (OTRA) has become a very popular topic for research. This active component has properties of dual relationship with operational transconductance amplifier (OTA), smaller impedances in input and output, and grounding virtually in input. In this paper, the proposed circuit is mainly realized employing a second order voltage-mode universal filter, and performed by Design of Nodal Analytical Method. The proposed circuit has three inputs and one ouput, and it is fulfilled with five filter functions; that is low-pass, high-pass, band-pass, band-reject, and all-pass in unchanging circuit structures. And it also uses three OTRA as active components, eight resistors, and two capacitors as passive components. On the other hand, the integration of circuit is also the important issue in this paper, referring the past methods by scholars and substitute MOSFET to resistors. The output signals have more high precisions with MOSFET than resistors, so it means that there is an advantage to complete circuit integration with MOSFET. What’s more, few components not only lift higher output precisions, smaller circuit areas , smaller power consumptions but have lower sensitivities in total circuit. Finally, the proposed circuit of this paper is simulated using TSMC035μm process parameters, and validated by simulation results and theoretical ones.
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陳俊成. "The Product Strategies of Mixed-mode Signal IC Design - a Case Study on Capacitive Sensor Button." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/68014490452451091084.
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Pan, Jyun-Ting, and 潘俊廷. "Generation and Comparison of Voltage-Mode Fourth-Order Elliptic Filters with Four OTRAs and Five Capacitors." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/11615113000283359443.
Full textAbstract:
碩士中原大學
電機工程研究所
101
This paper describes how analytical synthesis method generates the voltage-mode fourth-order elliptic lowpass filter with Operational Trans-resistance Amplifiers (OTRAs). Because it has variety character, namely, it has four types of circuits, we compare simulations of these circuits that use H-SPICE with TSMC SPICE MODEL 0.35μm process. After that we get best circuit is circuit of the capacitor in OTRAs feedback loop. In tradition, design circuit with OTRA usually supposes both trans-resistance gain (Rm) and bandwidth are infinite value, but, in fact, because of R_m is finite value and changed with frequency and bandwidth is finite value, the results of simulation showed error. This paper analyzes circuit of the capacitor in OTRAs feedback loop has error by effect on non-ideal OTRA. And then we use this analysis of non-ideal OTRA to compensate passive elements that can make accurate in result of simulation.
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Liu, I.-Te, and 劉奕德. "A 41.5dB SNR 500fps Current Mode Capacitive Touch Sensor with Discrete Time Charge-Rotating Filter for In-cell Touch Panel." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/yby39t.
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Huang, Cing-Jhong, and 黃慶鐘. "Non-ideal Effect of the Voltage-Mode High-Frequency Biqued Filter structure with Four Single-Ended-Input OTAs and Two Grounded Capacitors." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/30527687518907162311.
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碩士中原大學
電機工程研究所
95
It is worthy of research to do the analogue circuit design using Operational Transconductance Amplifiers (OTAs) and Capacitors (Cs) because an OTA is equivalent to both an active element and a resistor leading to a more condensed integrated circuit without resistors, and because the equivalent resistor value can be electronically tuned varying the bias current. Though the structure of the circuit has already been simplified, but manufacturing technology of integrated circuit (IC) of now unable to make circuit very much accurate, will is it output signal produce certain error by signal with theory , every parasitic effect that node produce of adding structure of circuit to make, can is it output signal produce certain error with theory signal , especially when operation of circuit frequency high to make too, this parasitic effect will be more and more obvious, make the whole circuit operate when high-frequency, what the discussion of the parasitic or factors produced changes is very important. The thesis is focused on the design of biquads using tunable OTA, leading to very precise output responses such as allpass, highpass, lowpass, bandpass, band-reject, and highpass filtering signals.The study steps of this thesis is following: step1. simulation result; step2. worst case simulation ;; step3. designing the butterworth filter; step4. sensitivity simulation; step5. eliminating error; step7. non-ideal analysis。 Finally, the H-spice simulation with TSMC035 process verifies the theoretical predictions.
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Lin, Ting-Tsan, and 林廷燦. "Design of dual mode of feeding structure for single conductor strip leaky wave antenna and four ports beam switching antenna using capacitive gap coupled ACPW resonator." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/82583229267402058198.
Full textAbstract:
碩士國立交通大學
電信工程研究所
103
This thesis consist of two parts: dual mode of feeding structure for single conductor strip leaky wave antenna and four ports beam switching antenna using capacitive gap coupled ACPW resonator. In the first part, the dual mode of feeding structure for single conductor strip leaky wave antenna is proposed. There is a PEC/PMC wall assumed at the center of the single conductor strip. Firstly, in order to excite dual mode of single conductor leaky wave antenna, the broadband feeding structure which can generate out-of-phase and in-phase signal is designed. In second step, we combine the broadband feeding network and the single conductor strip leaky wave antenna, the antenna will have different radiation characteristic. One mode make main beam toward end fire direction, the other mode can make the radiation behave as long wire antenna. In our second design, the four ports beam switching antenna using capacitive gap coupled ACPW resonator is proposed. The asymmetric ground of ACPW alters the ground current in purpose, which enhances the radiation from the structure. This characteristic can be well suited in antenna applications. We use the theory of band-pass filter to make this antenna. This antenna will generate different radiation pattern by different feeding signals. The antenna of ACPW structure is easily affected by CPW or micro-strip transmission line. Thus, four ports feeding network of strip-line form that can generate four kinds feeding signal to antenna is presented. The four ports feeding network of strip-line form that can generate four kinds feeding signal to antenna is presented. When the feeding network combine with the antenna using ACPW resonator coupled capacitive gap, we can obtain the beam switching antenna by feeding different port.
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Ghosh, Diptendu. "Circuit techniques for the design of power-efficient radio receivers." Thesis, 2010. http://hdl.handle.net/2152/ETD-UT-2010-12-2309.
Full textAbstract:
The demand for low power wireless transceiver implementations has
been fueled by multiple applications in the recent decades, including cellular
systems, wireless local area networks, personal area networks, biotelemetry and sensor networks. Dynamic range, which is set by linearity and sensitivity performance, is a critical design metric in many of these systems. Both linearity and sensitivity requirements continue to become progressively challenging in
many systems due to greater spectrum usage and the need for high data rates respectively. The objective of this research is to investigate power-efficient
circuit techniques for reducing the power requirement in receiver front-ends without compromising the dynamic range performance.
In the first part of the dissertation, a low power receiver down-converter topology for enhancing dynamic range performance is presented. Current
mode down-converters with passive mixer cores have been shown to provide excellent dynamic range performance. However, in contrast to a current commutating
Gilbert cell, these down-converters require separate bias current paths for the RF transconductor and the baseband transimpedance amplifier.
The proposed topology reduces the power requirement of conventional
current mode passive down-converter by sharing the bias current between the transconductance and transimpedance stages. This is achieved without compromising
the available voltage headroom for either stage, which is a limitation
of bias-sharing based on the use of stacked stages. The dynamic range of the basic bias-current-shared topology is further enhanced through suppression of
low frequency noise and IM3 products. Two variants of the down-converter, employing a broadband common-gate and a narrowband common-source input stage, are implemented in a 0.18-μm CMOS technology. The dynamic range performance of the architecture is analyzed. Finally, a prototype of a
full direct-conversion receiver implementation with quadrature outputs and integrated LO synthesis is demonstrated.
A power-efficient oscillator design for phase noise minimization is presented
in the second part of this dissertation. This design is targeted towards multi-radio platforms where several communication links operate simultaneously over multiple frequency bands. Blockers from concurrently operating radios present a major design challenge. The blockers not only make the frontend linearity requirement more stringent but also degrade receiver sensitivity through reciprocal mixing with the phase noise sidebands of LO. Phase noise
minimization is thus critical for ensuring high sensitivity in frequency bands where large blockers are present and not sufficiently attenuated by pre-select filters.
A capacitive power combining technique in oscillators is introduced to improve phase noise performance. By combining this approach with current reuse,
the phase noise is reduced at lower power, compared to conventional LC oscillators. This leads to improved power efficiency. Moreover, the technique
mitigates modeling uncertainty arising from phase noise reduction through simultaneous impedance and current scaling. The mode selection in this oscillator,
which employs multiple coupled resonators, is analyzed and the impact of coupling on far-out phase noise performance is discussed.
Multi-mode oscillation can potentially arise in other oscillator topologies too, e.g., in multiphase oscillators. Mode selection in a widely used
transistor-coupled quadrature oscillator is analyzed in detail in the final part of the dissertation. The analysis shows how cross-compression among multiple competing modes can lead to suppression of non-dominant modes in the steady state.text
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Javed, Gaggatur Syed. "Integrated Interfaces for Sensing Applications." Thesis, 2016. http://hdl.handle.net/2005/2914.
Full textAbstract:
Sensor interfaces are needed to communicate the measured real-world analog values to the base¬band digital processor. They are dominated by the presence of high accuracy, high resolution analog to digital converters (ADC) in the backend. On most occasions, sensing is limited to small range measurements and low-modulation sensors where the complete dynamic range of ADC is not utilized. Designing a subsystem that integrates the sensor and the interface circuit and that works with a low resolution ADC requiring a small die-area is a challenge. In this work, we present a CMOS based area efficient, integrated sensor interface for applications like capacitance, temperature and dielectric-constant measurement. In addition, potential applica-tions for this work are in Cognitive Radios, Software Defined Radios, Capacitance Sensors, and location monitoring.
The key contributions in the thesis are:
1 High Sensitivity Frequency-domain CMOS Capacitance Interface: A frequency domain capacitance interface system is proposed for a femto-farad capacitance measurement. In this technique, a ring oscillator circuit is used to generate a change in time period, due to a change in the sensor capacitance. The time-period difference of two such oscillators is compared and is read-out using a phase frequency detector and a charge pump. The output voltage of the system, is proportional to the change in the input sensor capacitance. It exhibits a maximum sensitivity of 8.1 mV/fF across a 300 fF capacitance range.
2 Sensitivity Enhancement for capacitance sensor: The sensitivity of an oscillator-based differential capacitance sensor has been improved by proposing a novel frequency domain capacitance-to-voltage (FDC) measurement technique. The capacitance sensor interface system is fabricated in a 130-nm CMOS technology with an active area of 0.17mm2 . It exhibits a maximum sensitivity of 244.8 mV/fF and a measurement resolution of 13 aF in a 10-100 fF measurement range, with a 10 pF nominal sensor capacitance and an 8-bit ADC.
3 Frequency to Digital Converter for Time/Distance measurement: A new architecture for a Vernier-based frequency-to-digital converter (VFDC) for location monitoring is pre¬sented, in which, a time interval measurement is performed with a frequency domain approach. Location monitoring is a common problem for many mobile robotic applica¬tions covering various domains, such as industrial automation, manipulation in difficult areas, rescue operations, environment exploration and monitoring, smart environments and buildings, robotic home appliances, space exploration and probing. The proposed architecture employs a new injection-locked ring oscillator (ILR) as the clock source. The proposed ILR oscillator does not need complex calibration procedures, usually required by Phase Locked Loop (PLL) based oscillators in Vernier-based time-to-digital convert¬ers. It consumes 14.4 µW and 1.15 mW from 0.4 V and 1.2 V supplies, respectively. The proposed VFDC thus achieves a large detectable range, fine time resolution, small die size and low power consumption simultaneously. The measured time-difference error is less than 50 ps at 1.2 V, enabling a resolution of 3 mm/kHz frequency shift.
4 A bio-sensor array for dielectric constant measurement: A CMOS on-chip sensor is presented to measure the dielectric constant of organic chemicals. The dielectric constant of these chemicals is measured using the oscillation frequency shift of a current controlled os¬cillator (CCO) upon the change of the sensor capacitance when exposed to the liquid. The CCO is embedded in an open-loop frequency synthesizer to convert the frequency change into voltage, which can be digitized using an off-chip analog-to-digital converter. The dielectric constant is then estimated using a detection procedure including the calibration of the sensor.
5 Integrated Temperature Sensor for thermal management: An integrated analog temper¬ature sensor which operates with simple, low-cost one-point calibration is proposed. A frequency domain technique to measure the on-chip silicon surface temperature, was used to measure the effects of temperature on the stability of a frequency synthesizer. The temperature to voltage conversion is achieved in two steps i.e. temperature to frequency, followed by frequency to voltage conversion. The output voltage can be used to com¬pensate the temperature dependent errors in the high frequency circuits, thereby reduc¬ing the performance degradation due to thermal gradient. Furthermore, a temperature measurement-based on-chip self test technique to measure the 3 dB bandwidth and the central frequency of common radio frequency circuits, was developed. This technique shows promise in performing online monitoring and temperature compensation of RF circuits.