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Dissertations / Theses on the topic 'Electronic systems – Noise'

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Published: 4 June 2021
Last updated: 1 February 2022

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1

Chamon, Cláudio de Carvalho. "Electronic conduction and noise in strongly correlated systems." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/38772.

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2

Tomlin, Toby-Daniel. "Analysis and modelling of jitter and phase noise in electronic systems : phase noise in RF amplifiers and jitter in timing recovery circuits." University of Western Australia. School of Electrical, Electronic and Computer Engineering, 2004. http://theses.library.uwa.edu.au/adt-WU2004.0021.

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Timing jitter and phase noise are important design considerations in most electronic systems, particularly communication systems. The desire for faster transmission speeds and higher levels of integration, combined with lower signal levels and denser circuit boards has placed greater emphasis on managing problems related to phase noise, timing jitter, and timing distribution. This thesis reports original work on phase noise modelling in electronic systems. A new model is proposed which predicts the up-conversion of baseband noise to the carrier frequency in RF amplifiers. The new model is validated by comparing the predicted phase noise performance to experimental measurements as it applies to a common emitter (CE), bipolar junction transistor (BJT) amplifier. The results show that the proposed model correctly predicts the measured phase noise, including the shaping of the noise about the carrier frequency, and the dependence of phase noise on the amplifier parameters. In addition, new work relating to timing transfer in digital communication systems is presented. A new clock recovery algorithm is proposed for decoding timing information encoded using the synchronous residual time-stamp (SRTS) method. Again, theoretical analysis is verified by comparison with an experimental implementation. The results show that the new algorithm correctly recovers the source clock at the destination, and satisfies the jitter specification set out by the ITU-T for G.702 signals.
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3

Aghassi, Jasmin [Verfasser]. "Electronic transport and noise in quantum dot systems / J. Aghassi." Karlsruhe : Forschungszentrum Karlsruhe, 2007. http://d-nb.info/986920967/34.

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4

Burdi, Muhammad Khan. "Fault locator for distribution systems, utilising fault arc noise." Thesis, University of Bath, 1994. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.387152.

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5

Gurrie, Thomas M. "The application of system modelling to digital electronic systems for active control of acoustic noise." Thesis, Royal Holloway, University of London, 1988. http://repository.royalholloway.ac.uk/items/57091fab-773a-4d31-b806-77ba916cb6f9/1/.

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Active noise control (ANC) is concerned with achieving some degree of cancellation between unwanted acoustic noise and the output from one or more actively controlled secondary sources. The minimum configuration for an A.N.C. system is a detecting microphone to detect the unwanted acoustic noise and a single loudspeaker to act as a secondary source. The basic problem is to specify the electronic system needed between the detecting microphone and the loudspeaker to achieve cancellation. The system has an inherent feedback pathbetween the loudspeaker and the detecting microphone that may cause instability. The system described in this thesis uses the principle of parallel feedback to ensure system stability. The basic idea of this is to use a second electronic system in a feedback path parallel to the electroacoustic feedback path to, in effect, remove this feedback. Incorporating both this feedback modelling and the appropriate forward transfer function between thedetecting microphone and the loudspeaker should produce a practical stable working system. This thesis considers implementation of these two electronic systems as sampled data systems employing finite impulse response (FIR) filters. Measurements on an experimental duct are used as input data for the study of system performance, this data being analysed using aleast squares approach to find best fit. FIR filters. The system is assessed in terms of the lengths of FIR filters required in the feedforward and feedback paths to achieve satisfactory operation, i.e. that the system produce a significant level of attenuation and be stable. The predicted level of performance of the ANC system indicates that the use of two independent FIR filters to model the feedforward and feedback paths produces a stable working system, capable of producing a significant level of attenuation over a broad frequency range. However, the length of FIR filter needed in each path has to be long in order to achieve a satisfactory level of performance.
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6

Aghassi, Jasmin. "Electronic Transport and Noise in Quantum Dot Systems Elektronischer Transport und Stromrauschen in Quantenpunktsystemen /." Karlsruhe : Forschungszentrum Karlsruhe, 2007. http://d-nb.info/986920967/34.

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7

Horst, Stephen J. "Frequency synthesis applications of SiGe BiCMOS processes." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/42815.

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Silicon Germanium BiCMOS technology has been demonstrated as an ideal platform for highly integrated systems requiring both high performance analog and RF circuits as well as large-scale digital functionality. Frequency synthesizers are ideal candidates for this technology because the mixed-signal nature of modern frequency synthesis designs fundamentally requires both digital and analog signal processing. This research targets three areas to improve SiGe frequency synthesizers. A majority of this work focuses on applying SiGe frequency synthesizers to extreme environment applications such as space, where low temperatures and ionizing radiation are significant design issues to contend with. A second focus area involves using SiGe HBTs to minimize noise in frequency synthesizer circuits. Improved low frequency "pink" noise in SiGe HBTs provide a significant advantage over CMOS devices, and frequency synthesis circuits are significantly affected by this type of noise. However, improving thermal "white" noise is also considered. Finally, an analysis of AM-PM distortion is considered for SiGe HBTs. The studies presented focus on identifying the physical mechanisms of observed phenomena, such as single event transients or phase noise characteristics in oscillators. The ultimate goal of this research is to provide a reference of effective design parameters for circuit and system designers seeking to take advantage of the properties of SiGe device physics.
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8

Kamanzi, Janvier. "Development of a low energy cooling technology for a mobile satellite ground station." Thesis, Cape Peninsula University of Technology, 2013. http://hdl.handle.net/20.500.11838/1072.

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Thesis submitted in fulfillment of the requirements for the degree Master of Technology:Electrical Engineering in the Faculty ofEngineering at the Cape Peninsula University of Technology Supervisor:Prof MTE KAHN Bellville December 2013
The work presented in this thesis consists of the simulation of a cooling plant for a future mobile satellite ground station in order to minimize the effects of the thermal noise and to maintain comfort temperatures onboard the same station. Thermal problems encountered in mobile satellite ground stations are a source of poor quality signals and also of the premature destruction of the front end microwave amplifiers. In addition, they cause extreme discomfort to the mission operators aboard the mobile station especially in hot seasons. The main concerns of effective satellite system are the quality of the received signal and the lifespan of the front end low noise amplifier (LNA). Although the quality of the signal is affected by different sources of noise observed at various stages of a telecommunication system, thermal noise resulting from thermal agitation of electrons generated within the LNA is the predominant type. This thermal noise is the one that affects the sensitivity of the LNA and can lead to its destruction. Research indicated that this thermal noise can be minimized by using a suitable cooling system. A moveable truck was proposed as the equipment vehicle for a mobile ground station. In the process of the cooling system development, a detailed quantitative study on the effects of thermal noise on the LNA was conducted. To cool the LNA and the truck, a 2 kW solar electric vapor compression system was found the best for its compliance to the IEA standards: clean, human and environment friendly. The principal difficulty in the development of the cooling system was to design a photovoltaic topology that would ensure the solar panels were always exposed to the sun, regardless the situation of the truck. Simulation result suggested that a 3.3 kW three sided pyramid photovoltaic topology would be the most effective to supply the power to the cooling system. A battery system rated 48 V, 41.6 Ah was suggested to be charged by the PV system and then supply the power to the vapor compression system. The project was a success as the objective of this project has been met and the research questions were answered.
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9

Wang, Liuqing. "Etude et développement de nouveaux matériaux et structures électroactifs pour la récupération d'énergie." Thesis, Lyon, INSA, 2014. http://www.theses.fr/2014ISAL0083/document.

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La croissance formidable des dispositifs sans fils et autonomes (réseaux de capteurs, objets connectés…) voit actuellement son développement limité par les batteries qui présente une durée de vie limitée et ainsi soulève des problèmes de maintenance. Afin de palier à cette limitation, l’utilisation de l’énergie directement disponible dans l’environnement immédiat du dispositif, conduisant au concept de « récupération d’énergie », est une voie fortement explorée depuis une dizaine d’années. Ainsi, l’objectif de cette thèse a été de développer de nouvelles techniques et/ou d’utiliser de nouveaux principes de conversion afin de proposer des alternatives aux techniques de récupération d’énergie classiques. Dans un premier temps, l’optimisation de récupérateurs électrostatiques a été étudiée. Les performances de ces systèmes étant fortement liées à la variation de capacité, une structure fractale, permettant un accroissement important des surfaces en regard entre deux électrodes (et donc de la capacité) lorsque ces dernières sont proches, a été proposée et modélisée. Il est ainsi montrer un accroissement significatif des possibilités de récupération d’énergie ; ces dernières étant étroitement liées à l’amplitude de vibration du système. Le second axe de recherche de cette thèse s’est attelé à développer un modèle haut niveau simple mais précis pour les structure utilisant des polymères électrostrictifs fonctionnant en flexion. Une analyse énergétique a permis de mettre en place un modèle électromécanique masse-ressort-amortisseur couplé avec une source de courant contrôlée par les excitations mécaniques et électriques du système, permettant ainsi une conception plus aisée du microgénérateur. Enfin, la dernière partie de cette thèse s’est intéressée à la conversion d’énergie thermique utilisant la variation de perméabilité des matériaux ferromagnétiques, ouvrant de nouvelles possibilités de conversion de l’énergie. En particulier, une technique simple et autonome consiste à créer un champ magnétique de polarisation à l’aide d’un aimant, permettant une variation du flux magnétique lors d’un changement de température, qui peut être converti sous forme électrique à l’aide d’un bobinage
This thesis has been devoted to electrostatic mechanical energy harvesting based on capacitors inspired by fractal geometry, to mechanical energy harvesting based on beams with electrostrictive polymers, and to thermal energy harvesting based on ferromagnetic materials. For electrostatic energy harvesting without electrets, interdigitated capacitors are usually applied as in-plane overlap varying and in-plane gap closing electrostatic generators. In consideration of the limit of aspect ratio for fingers in the capacitor, we would like to improve the capacitor configuration by taking advantage of self-similarity patterns. The concept is to gradually add fingers of smaller widths between original ones to form a mountain-shape capacitor. According to the different width ranges of capacitors, they are classified as of different orders whose performances vary with the vibration amplitude. Harvested energy over one cycle for capacitors of order 1, 2 and 3 has been demonstrated by theoretical and FEM results. In application, the order of capacitor needs to be properly chosen to maximize the harvested energy. Electrostrictive polymer (polyurethane) has been utilized along with a beam to perform mechanical energy harvesting. Two models have been analyzed: clamped-free beam with a polymer film attached at the clamped end, clamped-free bimorph beam. The simple model for electrostrictive devices under flexural solicitation is set up on the base of analysis of energy conversion and it shows that the electrostrictive system can be reduced to a simple spring-mass-damper system with a quadratic dependence with the applied voltage on the mechanical side and to a current source controlled by the applied voltage with a capacitive internal impedance on the electrical side. Experiments based on the clamped-free beam with a polymer film attached to the clamped end have been carried out to evaluate the mechanical to electrical conversion. The thermal energy generator is based on a ferromagnetic material, a magnet and a coil. As the magnetic permeability of ferromagnetic materials encounters drastic variation around the Curie temperature, the concept of the generator is to take advantage of the permeability variation caused by temperature decrease to generate sharp variation in magnetic flux which induces a current in the coil. According to theoretical results, the generated current is closely related to the temperature variation and the variation velocity. Experiments have been carried out on Ni30Fe of which the Curie temperature is 55 ºC. When the temperature decreases from 20.5 ºC to -42.4 ºC, the maximum power is about 4×10^(-7)W with the load to be 2 Ω
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10

Searle, Graham Ellis. "Dynamic modelling of electronic nose systems." Thesis, University of Warwick, 2002. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.251118.

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11

Ham, Donhee Hajimiri Ali. "Statistical electronics : noise processes in integrated communication systems /." Diss., Pasadena, Calif. : California Institute of Technology, 2002. http://resolver.caltech.edu/CaltechETD:etd-03162005-141416.

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12

Yates, James W. T. "Black box and mechanistic modelling of electronic nose systems." Thesis, University of Warwick, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.413428.

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13

Nimmagadda, Srinivas 1968. "Simultaneous switching noise and its impact on CMOS digital systems." Thesis, The University of Arizona, 1992. http://hdl.handle.net/10150/278252.

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Simultaneous switching noise was calculated for a number of CMOS drivers switching together. CMOS receiver noise immunity and the feed through of simultaneous switching noise from a D.C. "ON" driver were studied. The effects of skewing output driver switching on the simultaneous switching noise were explained. The performance trade-offs in using a damping resistor to minimize switching noise were analyzed. A distributed lumped equivalent model has been developed to model signal propagation over noisy reference planes, and thereby to accurately predict the overall noise levels in a system. The impact of package pin distribution on noise on the reference plane was analyzed.
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14

McCord, Cameron Forrest. "Electronic Sound Analysis with Hardware System and Remote Internet Display." Thesis, University of North Texas, 2010. https://digital.library.unt.edu/ark:/67531/metadc103358/.

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Currently, standards from government agencies such as the National Institute for Occupation Safety and Health exist to aid in safeguarding individuals’ capacity for hearing, but only in factory settings in which large machines often produce loud levels of sound. Neglecting the fact that these preventative measures are only in place in the most limited of settings, no system currently exists to observe and report sound exposure levels in a manner timely or easily recognizable enough to adequately serve its purpose of hearing conservation. Musicians may also incur significant levels of risk for hearing loss in their day-to-day rehearsals and concerts, from high school marching bands to university wind bands. As a result, music school accrediting organizations such as the National Association of Schools of Music and even the European Union have begun taking steps meant to determine the risks associated with music. To meet these goals and improve upon current technologies, a system has been developed that electronically records sound levels utilizing modern hardware, increases the speed of reporting by transmitting data over computer networks and the Internet, and displays measures calculated from these data in a web browser for a highly viewable, user-friendly interface.
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15

Kirton, Peter. "Fluctuations and noise in nanoelectrical and nanomechanical systems." Thesis, University of Nottingham, 2012. http://eprints.nottingham.ac.uk/12853/.

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In this thesis we present a study of the fluctuations and noise which occur in a particular nanoelectrical device, the single electron transistor (SET). Electrical transport through the SET occurs through a combination of stochastic, incoherent tunnelling and coherent quantum oscillations, giving rise to a rich variety of transport processes. In the first section of the thesis, we look at the fluctuations in the electrical properties of a SET. We describe the SET as an open quantum system, and use this model to develop Born-Markov master equation descriptions of the dynamics close to three resonant transport processes: the Josephson quasiparticle resonance, the double Josephson quasiparticle resonance and the Cooper-pair resonances. We use these models to examine the noise properties of both the charge on the SET island and the current flowing through the SET. Quantum coherent oscillations of Cooper-pairs in the SET give rise to noise spectra which can be highly asymmetric in frequency. We give an explicit calculation of how an oscillator capacitively coupled to the SET island can be used to infer the quantum noise properties close to the Cooper-pair resonances. To calculate the current noise we develop a new technique, based on classical full counting statistics. We are able to use this technique to calculate the effect of the current fluctuations on an oscillator coupled to the current through the SET, the results of which are in good agreement with recent measurements. In the final part of the thesis we explore the coupled dynamics of a normal state SET capacitively coupled to a resonator in the presence of an external drive. The coupling between the electrical and mechanical degrees of freedom leads to interesting non-linear behaviour in the resonator. We are able to find regions where the resonator has two possible stable amplitudes of oscillation, which can lead to a bistability in the dynamics. We also look at the fluctuations in the energy of the system. We use numerical methods to simulate the dynamics of the system, and to obtain the probability distribution for the work done, whose form can be interpreted by the appropriate fluctuation relation.
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16

Tashtoush, Nehad M. "SAW humidity sensor and an environmental electronic nose system." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq25915.pdf.

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17

Yoo, Seungyup. "Field effect transistor noise model analysis and low noise amplifier design for wireless data communications." Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/13024.

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18

Zhang, Dan. "Impulse noise detection techniques for retransmission to reduce delay in DSL systems." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=107853.

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To protect Digital Subscriber Line (DSL) systems against impulse noise (IN), interleaving combined with Reed-Solomon (RS) coding is typically deployed in the conventional DSL standards. However, interleaving introduces a long delay. To reduce such delay in conventional DSL systems that are corrupted by IN, retransmission can be used instead of interleaving. For an effective retransmission, reliable detection of corruption due to IN is required. In this thesis, we consider three detection approaches. The first one is based on the RS decoding status since the decoder either detects the number of corrected errors or reports the failure of decoding when the errors exceed its correction capability. Retransmission is required when the transmitted codeword cannot be decoded. The second one uses the square distance method in which erasures are marked for unreliably received samples and retransmission is issued when the number of erased samples exceeds a certain threshold. Finally, the third one takes advantage of the unused tones in DSL systems in order to detect whether IN is present. For all the above approaches, we analyze the average retransmission delay and bit error rate (BER) and provide simulation results to validate the analysis. It is found that the "Decoding Status" approach can reliably indicate received signals corrupted by IN. We consider it a trustful way to correct the symbols and detect the errors since the probability of wrong decoding for the received symbol is very low. In the frequency selective fading channel and with the presence of Repetitive Electrical Impulse Noise (REIN), numerical results using different parameters such as various channel responses and IN powers show that retransmission offers a short delay while effectively avoiding transmission errors. Specifically, with the "Decoding Status" approach, the error caused by REIN can be completely avoided with the average retransmission delay of around 0.029ms and the maximum round-trip delay of 0.75ms.
Pour protéger les systèmes de ligne d'abonné numérique (DSL) contre le bruit impulsif (IN), les normes conventionnelles de DSL sont typiquement déployées avec de l'entrelacement combiné au codage Reed-Solomon (RS). Cependant, l'entrelacement introduit un long retard. Afin de réduire ce retard dans les systèmes conventionnels de DSL qui sont corrompus par l'IN, une retransmission peut être utilisée au lieu de l'entrelacement. Pour une retransmission efficace, une détection fiable de l'altération causée par l'IN est nécessaire. Dans cette thèse, nous considérons trois approches de détection. La première est basée sur le statut du décodage RS puisque le décodeur détecte le nombre d'erreurs corrigées ou bien signale qu'il a échoué quand le nombre d'erreurs dépassent sa capacité de correction. Une retransmission est nécessaire quand le mot codé transmis ne peut pas être décodé. La deuxième méthode emploie la méthode des distances carrées dans laquelle les suppressions sont marquées pour les échantillons reçus non fiables et une retransmission est émise quand le nombre d'échantillons supprimés dépasse un certain seuil. Enfin, la troisième méthode est de profiter des tonalités inutilisées dans les systèmes de DSL afin de détecter si l'IN est présent. Pour toutes les approches ci-dessus, nous analysons le retard moyen et le taux d'erreur sur les bits (BER) et nous fournissons des résultats de simulation pour valider l'analyse. Il est constaté que l'approche du statut de décodage peut indiquer de manière fiable les signaux reçus corrompus par IN et nous le considérons comme une manière efficace pour corriger les symboles et pour détecter les erreurs puisque la probabilité de mauvais décodage pour le symbole reçu est très basse. Dans la voie sujette à évanouissement progressif de fréquences avec la présence de bruit électrique impulsif répétitif (REIN), les résultats numériques utilisant des paramètres différents tels que de diverses réponses de voies de transmission et de diverses puissances du IN prouvent que la retransmission offre un court retard tout en évitant efficacement les erreurs de transmission. Spécifiquement, avec l'approche du statut de décodage, l'erreur provoquée par le REIN peut complètement être évitée avec un délai de retransmission moyennant 0.029ms et un retard aller-retour maximale est de 0.75ms.
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19

Al-Masri, Mohammad Basel 1966. "Reducing coupling noise in VLSI packages using expert systems techniques." Thesis, The University of Arizona, 1992. http://hdl.handle.net/10150/278148.

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The level of coupling noise or cross talk is an important factor in the design of reliable VLSI packages. Coupling noise can be reduced by modifying the underlying conductor geometry. An expert system is developed and integrated into the packaging design and simulation environment UAPDSE. The system is provided with rules to reduce the coupling noise, and create models that satisfy the constraints set by the package designer. The parameter calculator UAMOM and the circuit simulator UANTL are used to evaluate the electrical performance of the model under study. The expert system is an interactive and user-friendly software that provides efficient method for performing the coupling noise reduction in interconnect systems.
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20

Rajashekharaiah, Mallesh. "Gain control and linearity improvement for low noise amplifiers in 5GHZ direct conversion receivers." Online access for everyone, 2005. http://www.dissertations.wsu.edu/Thesis/Spring2005/m%5Frajashekharaiah%5F050405.pdf.

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21

Cui, Li. "Conducting polymer-based QCM-interdigitated electrode hybrid electronic nose system." Thesis, University of Glasgow, 1999. http://theses.gla.ac.uk/3974/.

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This research project was concerned with the establishment and characterisation of a quartz crystal microbalance (QCM) - conductimetric interdigitated electrode hybrid "second generation" Electronic Nose system. Research objectives covered a number of technical limitations and analytical difficulties existed in the "first generation" Electronic Nose system. A wide variety of work was carried out, including the design and fabrication of the electronic nose system, the optimisation of sensors response, the device modelling, the studies of vapour-polymer interaction mechanisms and the application of the electronic nose in multi-component analysis. A QCM-interdigitated electrode hybrid sensor odour measurement system was established, and sensor fabrication techniques developed. Some important parameters corresponding to sensor characteristics were investigated such as the conditions for polymer film polymerisation. By studying 16 different coatings, "optimal" individual initial resistances were proposed, which minimise long-term baseline resistance drift, whilst maintaining good sensitivity. A set of sensors was made with low initial resistance variation. Sensor detection dynamic range was found to be dependent on the type of the coating material and the film thickness. The response of a combined hybrid sensor pair remained stable during a test period of 45 days, which showed an improved stability. The principle of the sensor's response and device modelling were addressed. The vapour-polymer interactions and sensor pair's response were linked by a sensitivity coefficient (S), which was defined as the relative resistivity change by a single molecule absorbed into the polymer film. A pair of sensors showing concentration independence over a wide concentration range can be formed on separate QCM and interdigitated electrodes with the same polymer. The combined response (Srf) can be used to identify a particular vapour. Based on the concentration independence, the proposed "odour maps" showed the feasibility of distinguishing odourants using a significantly lower number of different types of sensor coatings. This demonstrated the improved selectivity of a hybrid system compared with the single property system.
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22

tariq, tariq. "GUI Application for measuring instrument. : Noise measurement system." Thesis, Uppsala universitet, Informationssystem, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-208326.

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The always growing demands on the electronics design of modern electron microscopes cause increased requirements to the measurement tasks in the electronics development of these systems. In this thesis, we report the findings of designing noise measurements setup in Carl-Zeiss, Oberkochen. The aim of this thesis was to explore the design setup for noise measurement and to provide an interface which help us analyze these measurements using C# and agilent multimeter. This was achieved by the construction and evaluation of a prototype for a noise measurment application. For this purpose Design Science Research (DSR) was conducted, situated in the domain of noise measurement research. The results consist of a set of design principles expressing key aspects needed to address when designing noise measurement functionality. The artifacts derived from the development and evaluation process each one constitutes an example of how to design for noise measurement functionality of this kind.
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23

Zhao, Yuxin. "Efficient erasure marking technique for delay reduction in DSL systems impaired by impulse noise." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=110650.

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Digital Subscriber Line (DSL) technologies have experienced rapid development. Protecting the DSL systems against Impulse Noise (IN) is an important issue and it has recently received considerable attention. A combination of Reed–Solomon (RS) codes and interleaving is used to mitigate the destructive effects of IN. However, it is shown that the interleaving structure introduces long delay, which is certainly undesirable in high-rate transmission systems supporting interactive applications such as Internet Protocol Television (IPTV). Different techniques have therefore been proposed to reduce the interleaving delay while still being able to effectively protect the systems from IN. In particular, Error and Erasure Decoding (EED) can be used instead of Error Decoding (ED) to improve the decoder correction capability, which in turn helps reducing the required interleaving depth and delay. To fully explore the error correction capacity of the EED, reliable erasure marking becomes essential. This thesis proposes an erasure marking technique that fully explores the correction capacity of the EED, and correspondingly, facilitates a shorter interleaving. We first study the sources that generate impulse noise and the statistics of impulse noise in DSL systems. Analytical models for the distribution of amplitude and inter-arrival time of impulse noise are also provided. Based on the statistics of impulse noise, a squared-distance based erasure marking technique is then proposed. Furthermore, analysis of selecting proper parameters for the proposed technique is developed. Finally, the Peak Signal-to-Noise Ratio (PSNR) performance of IPTV over DSL in presence of IN is investigated with the proposed erasure marking technique employed.
Les technologies de Ligne d'abonné numérique (DSL) ont connu un développement rapide. La protection des systèmes de DSL contre le bruit impulsif (IN) est une question importante et elle a récemment suscité attention considérable. Normalement, une combinaison decodes RS et d'entrelacement est employée pour atténuer les effets destructifs du IN. Mais, il est établi que la structure d'entrelacement introduit des longs retards qui sont certainement indésirables dans les systèmes de transmission à haut débit qui supportent des applications interactives telles que la télévision sur IP (IPTV). Donc, il existe des techniques différentes pour réduire le retard d'entrelacement tout en étant capables de protéger efficacement les systèmes contre l'IN. En particulier, le décodage d'erreur et d'effacement (EED) peut être utilisé au lieu du décodage d'erreur (ED) afin d'améliorer la capacité de correction du décodeur, qui, à son tour, contribue à réduire la profondeur de l'entrelacement requise et les retards. Pour explorer la capacité de correction d'erreurs de l'EED, une méthode fiable pour marquer les effacements devient très essentielle. Cette thèse propose une technique de marquage de l'effacement qui utilise pleinement la capacité de correction de l'EED, et, par conséquence, entraîne un entrelacement plus court. Nous étudions d'abord les sources qui produisent l'IN et les statistiques de l'IN dans les systèmes DSL. Des modèles analytiques sur la distribution de l'amplitude et de l'intervalle entre les arrivées de l'IN sont fournis. En se basant sur les statistiques de l'IN, nous proposons une technique de marquage des suppressions basée sur la distance carrée. De plus, une analyse de la sélection des paramètres appropriés pour la technique proposée est développée. Finalement, la performance du rapport puissance maximale instantanée sur bruit (PSNR) de l'IPTV dans les systèmes de DSL en présence de l'IN est examinée avec la technique de marquage des suppressions proposée.
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24

Pathange, Lakshmi Prasad. "Non-Destructive Evaluation of Apple Maturity Using an Electronic Nose System." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/41235.

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The apple growers and packaging houses are interested in methods that can evaluate the quality of apples non-destructively. Harvested fruits are a mixture of immature, mature, and over mature fruits, thereby posing a great problem in deciding their end use and storage time. It is expected that the technique developed from the present project could be effectively used to classify the harvested fruit into immature, mature and over mature apples, rapidly and non-destructively. It would also help the growers to predict the optimum dates to harvest the fruits. York and Gala were the varieties of apples that were used in this study and were obtained from Virginia Tech College of Agriculture and Life Sciences Kentland Farm. Apples were harvested at different times resulting in different maturity groups (immature, mature and ripe). Gala apples were harvested on three dates with an interval of 10 days, while York apples were harvested on four dates with an interval of 14 days. They were stored at 0oC until sampled. For each harvest date, the experiments were conducted in two sets (10 each) on two consecutive days. First the ethylene levels were measured, followed by gas chromatograph and electronic nose. Then the maturity indices were measured. Three maturity indices, starch index, firmness and soluble solids were used as the three variables for the statistical analysis to identify and categorize the fruits into three maturity categories referred as immature, mature and over mature fruits. Apples were also categorized into three maturity groups based on the emanation levels of the aroma compounds evolved from the fruits. Then electronic nose sensor responses were categorized into the above maturity categories, and their effectiveness was determined using a statistical procedure called Discriminant Analysis (DA). From the DA cross validation results the correct classification percentage for Gala and York apples into maturity groups was 95%. The Electronic nose sensorâ s effectiveness to categorize the same observations based on sensor responses in to the above classified maturity categories was 83% correct in case Gala apples and 69% for York apples. The EN sensors response data were analyzed by the EN system software and the correct classification percentage for Gala was 83% and for York was 81%. Aroma-based categorization for Gala apples was 100% correct, while the electronic nose for the same analysis was 80%. Based on the three physical parameters, an objective evaluation of maturity could be accomplished. Principal Component Analysis, Canonical Discriminant Analysis and DA results demonstrated that the electronic nose could be used to classify apples into three identified maturity-based groups. The EN sensors (Gala apples), could also classify the apples into aroma-based categories. Thus, it can be concluded that the EN system holds promise as non-destructive evaluation technique to determine the maturity of an apple.
Master of Science
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Martini, Guilherme Henrique Kaehler. "Filtro digital híbrido para sistemas embarcados de alta potência." Universidade Tecnológica Federal do Paraná, 2013. http://repositorio.utfpr.edu.br/jspui/handle/1/593.

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Esta dissertação trata sobre o projeto, implementação e avaliação de um filtro híbrido para supressão de ruído em sistemas de alta potência. Seu desempenho será otimizado para reduzir a magnitude de ruídos impulsivos, que são comuns em dispositivos de alta potência, como inversores de frequência que controlam motores trifásicos. O filtro híbrido proposto é avaliado empiricamente em um inversor de frequência que é controlado por um sistema embarcado. A abordagem proposta é comparada com abordagens clássicas de filtragem digital como média móvel, filtro de resposta finita ao impulso (FIR) e filtro de resposta infinita ao impulso (IIR).
This work presents the project, implementation and evaluation of a hybrid filter used for noise supressing in high power switching converters. It is optimized to reduce impulsive noise that is commonly present in high power devices like frequency inverters that control three-phase motors. The hybrid filter is evaluated empirically in a frequency inverter that is controlled by an embedded system. This approach is compared to classical ones, like the moving average, the finite impulse response (FIR) and the infinite impulse response (IIR) filters.
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26

Penrod, Logan B. "An Exploratory Study of Pulse Width and Delta Sigma Modulators." DigitalCommons@CalPoly, 2020. https://digitalcommons.calpoly.edu/theses/2278.

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This paper explores the noise shaping and noise producing qualities of Delta-Sigma Modulators (DSM) and Pulse-Width Modulators (PWM). DSM has long been dominant in the Delta Sigma Analog-to-Digital Converter (DSADC) as a noise-shaped quantizer and time discretizer, while PWM, with a similar self oscillating structure, has seen use in Class D Power Amplifiers, performing a similar function. It has been shown that the PWM in Class D Amplifiers outperforms the DSM [1], but could this advantage be used in DSADC use-cases? LTSpice simulation and printed circuit board implementation and test are used to present data on four variations of these modulators: The DSM, PWM, the out-of-loop discretized PWM (OOLDP), and the cascaded modulator. A generic form of an Nth order loop filter is presented, where three orders of this generic topology are analyzed in simulation for each modulator, and two orders are used in physical testing.
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Pang, Ho-Yuen. "Novel super-resolution algorithms and enhanced noise removal algorithm for image restoration systems and applications." Diss., The University of Arizona, 2002. http://hdl.handle.net/10150/279978.

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This dissertation is concerned with the introduction of a systematic way of modeling image processing. A dynamic imaging system model constructed from an information theory framework is proposed. Unlike an earlier simple model, the proposed dynamic imaging system (DIS) model is suitable for a wide range of applications. This DIS model is inspired by the Shannon communication theory. The Shannon communication theory is credited for the rapid development of the communication industry. Currently, most image processing researchers focus on developing fast algorithms and better hardware. An information theoretic-based approach to image processing could bring as large an impact to the image processing area as Shannon's communication theory had on the communications area. This proposed DIS model will use the information obtained from the acquired images to provide an estimation of the unknown atmospheric turbulence, vibration, etc. It will also automatically adjust the sampling rate, wavelength band, and algorithms of choice, to produce the best possible restored image with limited information under uncertainty. This dissertation develops the concept of the DIS model including its basic components. We have implemented three parts of this system. First, we implemented a noise removal algorithm based on the Markov random field (MRF). It is shown that this algorithm achieves better performance than other MRF-based algorithms in noise removal. Second, we have implemented a hybrid maximum likelihood/projection-on-convex-set image restoration algorithm and demonstrate that it outperforms the maximum likelihood algorithm. Third, we have implemented a self-organized map-based image restoration algorithm and compare its performance to several well-known methods. It can be implemented in parallel processing to achieve super-resolution in real time without performing a time consuming iteration process. The impact of the development of these DIS system critical components is discussed and future research areas are elucidated.
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Figueiredo, Susana Afonso de Barros. "The use of an electronic nose for monitoring odours from waste composting systems." Thesis, University of Leeds, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.400263.

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Van, Deventer David. "Discrimination of Retained Solvent Levels in Printed Food-Packaging Using Electronic Nose Systems." Thesis, Virginia Tech, 2000. http://hdl.handle.net/10919/9741.

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The expanding role of electronic nose instrumentation, as a quality-monitoring tool for food-packaging materials, is examined and reviewed. The food industry is interested in determining the applicability of using an electronic nose for odor analysis of retained printing solvent levels in packaging. Three electronic nose systems were optimized for this application and their performance assessed. These include the FOX 3000, the Cyranose 320, and the QMB6. Response surface methodology was used to generate 2nd order models of sensor response as a function of system and experimental parameters for the three electronic nose systems. Forty-seven of 50 sensor models generated were found to be significant at an a-level of 0.05. Optimum settings, that allowed adequate signals to be obtained for the full range of examined retained solvents levels, were selected for the remaining work using these models. Performance analyses of these systems, which use three leading sensor technologies, showed that the conducting polymer sensor technology demonstrated the most discriminatory power. All three technologies proved able to discriminate among different levels of retained solvents. Each complete electronic nose system was also able to discriminate between assorted packaging having either conforming or non-conforming levels of retained solvents. Each system correctly identified 100% of unknown samples. Sensor technology had a greater effect on performance than the number of sensors used. Based on discriminatory power and practical features, the FOX 3000 and the Cyranose 320 were superior. The results indicate that electronic nose instrumentation can be used as a complimentary discriminatory tool in quality control.
Master of Science
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30

Nissfolk, Martin. "Development of an Electronic Nose-Tongue Data Acquisition System using a Microcontroller." Thesis, Uppsala University, Department of Information Technology, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-103095.

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An ad-hoc data acquisition system was constructed in order to control an array of different types of sensors and to collect their data. The system will be used as the core for electronic nose and tongue systems used for classifying and distinguishing different levels of contamination in water and other types of liquid. The system consists of analog and digital electronics as well as software for a microcontroller and a PC. The heart of the system is a PIC microcontroller that can communicate with the real world and with a PC. With the real world it is referred to analogue devices that measure things that are infinitely variable, they are not quantized like in the digital world which is an approximation of the real world. A microcontroller is a small computer fit into a single chip. This computer is a microprocessor together with memory and I/O ports. Microchip is a company that has produced popular microcontrollers called PIC’s. The microprocessor was programmed in the language C. The system can take samples at accurate time intervals. A LabVIEW program was developed so that the system can be controlled with a user friendly interface. The sensors can be monitored in the LabVIEW program and the data can be exported to a spread sheet text document, ready to be opened in another program for analysis. With serial transmission the designed data acquisition board cannot only be interfaced with LabVIEW on a PC running Windows, but also with Linux or Windows Mobile. The system is robust, economic and portable. The report tries to describe how the development was done.

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Dutta, Ritaban. "A novel approach to analysing electronic nose data : object oriented expert system." Thesis, University of Warwick, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.406818.

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Shin, Hyun Woo. "A hybrid electronic nose system for monitoring the quality of potable water." Thesis, University of Warwick, 1999. http://wrap.warwick.ac.uk/111031/.

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This PhD thesis reports on the potential application of an electronic nose to analysing the quality of potable water. The enrichment of water by toxic cyanobacteria is fast becoming a severe problem in the quality of water and a common source of environmental odour pollution. Thus, of particular interest is the classification and early warning of toxic cyanobacteria in water. This research reports upon the first attempt to identify electronically cyanobacteria in water. The measurement system comprises a Cellfacts instrument and a Warwick e-nose specially constructed for the testing of the cyanobacteria in water. The Warwick e- nose employed an array of six commercial odour sensors and was set-up to monitor not only the different strains, but also the growth phases, of cyanobacteria. A series of experiments was carried out to analyse the nature of two closely related strains of cyanobacteria, Microcystis aeruginosa PCC 7806 which produces a toxin and PCC 7941 that does not. Several pre-processing techniques were explored in order to remove the noise factor associated with running the electronic nose in ambient air, and the normalised fractional difference method was found to give the best PCA plot. Three supervised neural networks, MLP, LVQ and Fuzzy ARTMAP, were used and compared for the classification of both two strains and four different growth phases of cyanobacteria (lag, growth, stationary and late stationary). The optimal MLP network was found to classify correctly 97.1 % of unknown non-toxic and 100 % of unknown toxic cyanobacteria. The optimal LVQ and Fuzzy ARTMAP algorithms were able to classify 100% of both strains of cyanobacteria. The accuracy of MLP, LVQ and Fuzzy ARTMAP algorithms with 4 different growth phases of toxic cyanobacteria was 92.3 %, 95.1 % and 92.3 %, respectively. A hybrid e-nose system based on 6 MOS, 6 CP, 2 temperature sensors, 1 humidity sensor and 2 flow sensors was finally developed. Using the hybrid system, data were gathered on six different cyanobacteria cultures for the classification of growth phase. The hybrid resistive nose showed high resolving power to discriminate six growth stages as well as three growth phases. Even though time did not permit many series of the continuous monitoring, because of the relatively long life span (30-40 days) of cyanobacteria, improved results indicate the use of a hybrid nose. The HP 4440 chemical sensor was also used for the discrimination of six different cyanobacteria samples and the comparison with the electronic nose. The hybrid resistive nose based on 6 MOS and 6 CP showed a better resolving power to discriminate six growth stages as well as three growth phases than the HP 4440 chemical sensor. Although the mass analyser detects individual volatile chemicals accurately, it proves no indication of whether the volatile is an odour. The results demonstrate that it is possible to apply the e-nose system for monitoring the quality of potable water. It would be expected that the hybrid e-nose could be applicable to a large number of applications in health and safety with a greater flexibility.
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Miller, Michael E. "Effects of field of view, MTF shape, and noise upon the perception of image quality and motion." Diss., This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-10022007-145303/.

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34

Marusiak, David. "MOS CURRENT MODE LOGIC (MCML) ANALYSIS FOR QUIET DIGITAL CIRCUITRY AND CREATION OF A STANDARD CELL LIBRARY FOR REDUCING THE DEVELOPMENT TIME OF MIXED-SIGNAL CHIPS." DigitalCommons@CalPoly, 2014. https://digitalcommons.calpoly.edu/theses/1363.

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Many modern digital systems use forms of CMOS logical implementation due to the straight forward design nature of CMOS logic and minimal device area since CMOS uses fewer transistors than other logic families. To achieve high-performance requirements in mixed-signal chip development and quiet, noiseless circuitry, this thesis provides an alternative toCMOSin the form of MOS Current Mode Logic (MCML). MCML dissipates constant current and does not produce noise during value changing in a circuit CMOS circuits do. CMOS logical networks switch during clock ticks and with every device switching, noise is created on the supply and ground to deal with the transitions. Creating a noiseless standard cell library with MCML allows use of circuitry that uses low voltage switching with 1.5V between logic levels in a quiet or mixed-signal environment as opposed to the full rail to rail swinging of CMOS logic. This allows cohesive implementation with analog circuitry on the same chip due to constant current and lower switching ranges not creating rail noise during digital switching. Standard cells allow for the Cadence tools to automatically generate circuits and Cadence serves as the development platform for the MCML standard cells. The theory surrounding MCML is examined along with current and future applications well-suited for MCML are researched and explored with the goal of highlighting valid candidate circuits for MCML. Inverters and NAND gates with varying current drives are developed to meet these specialized goals and are simulated to prove viability for quiet, mixed-signal applications. Analysis and results show that MCML is a superior implementation choice compared toCMOSfor high speed and mixed signal applications due to frequency independent power dissipation and lack of generated noise during operation. Noise results show rail current deviations of 50nA to 300nA during switching over an average operating current of 20µA to 80µA respectively. The multiple order of magnitude difference between noise and signal allow the MCML cells to dissipate constant power and thus perform with no noise added to a system. Additional simulated results of a 31-stage ring oscillator result in a frequency for MCML of 1.57GHz simulated versus the 150.35MHz that MOSIS tested on a fabricated 31-stage CMOS oscillator. The layouts designed for the standard cell library conform to existing On Semiconductor ami06 technology dimensions and allow for design of any logical function to be fabricated. The I/O signals of each cell operate at the same input and output voltage swings which allow seamless integration with each other for implementation in any logical configuration.
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35

Simard, Frédéric. "The analysis and simulation of a generalized hybrid ARQ system for a burst-noise channel /." Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=59439.

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As digital systems become widespread, the importance of error control in these systems increases. Further, since most channels cannot be realistically modelled by a simple Binary Symmetric Channel, it is required to reliably estimate the performance of error control schemes on real channels. This thesis considers the analysis and simulation of a Generalised Hybrid ARQ Type II (GH-ARQ II) error control scheme on a channel modelled by the Gilbert-Elliott model. The analysis is easily extended to higher order systems and channels modelled by first-order Markov chains. The results indicate that the performance of the GH-ARQ II scheme improves as the errors in the channel become burstier in nature and that this scheme is well suited to channels with relatively slowly varying error statistics. Further, it is found that the roundtrip delay of the selective repeat retransmission strategy may affect the performance of this error control scheme on burst-noise channels.
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Chen, Hung Tat. "A portable electronic nose micro-system based on bio-inspired log-spike processing /." View abstract or full-text, 2009. http://library.ust.hk/cgi/db/thesis.pl?ECED%202009%20CHEN.

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37

Franklin, Daniel Robert. "Enhancements to channel models, DMT modulation and coding for channels subject to impulsive noise." School of Electrical, Computer & Telecommunications Engineering - Faculty of Informatics, 2007. http://ro.uow.edu.au/theses/18.

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DMT modulation is an OFDM-based modulation scheme used in ADSL and proposed for various other high-speed broadband access systems. Existing mathematical models for transmission lines make a number of simplistic assumptions about the distribution of noise, in particular, the assumption that impulsive noise originates at either end of the transmission line. It is therefore desirable to improve the accuracy of the transmission-line model to allow better prediction of broadband modem performance, and to further improve the bit-allocation algorithms and equaliser designs used in DMT-based modems. This Thesis presents a new channel model particularly well-suited for simulation of high-speed digital subscriber line systems. The model extends a commonly-used physical channel model by distributing the points of noise ingress along the physical length of the transmission line. Simulation results are presented for a highspeed multicarrier modem operating on channels modelled with both the conventional and new models. Comparison with the same modem operating over a real channel demonstrates that the new model provides a better estimate of the bit error rates and temporal error distribution expected on actual telephone lines than is possible with the conventional model. A number of improvements to modulation and coding schemes for DMT modems are also presented in this Thesis, including a robust frequency-domain decision feedback equaliser, a new algorithm for allocating bits to sub-carriers based on a measurement of per-carrier BER, and a technique for encoding data with fractional numbers of bits ii Abstract iii per symbol, thereby providing additional channel capacity.
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38

Lundgren, Jan. "Behavioral Level Simulation Methods for Early Noise Coupling Quantification in Mixed-Signal Systems." Licentiate thesis, Mittuniversitetet, Institutionen för informationsteknologi och medier, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-3434.

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In this thesis, noise coupling simulation is introduced into the behavioral level. Methods and models for simulating on-chip noise coupling at a behavioral level in a design flow are presented and verified for accuracy and validity. Today, designs of electronic systems are becoming denser and more and more mixed-signal systems such as System-on-Chip (SoC) are being devised. This raises problems when the electronics components start to interfere with each other. Often, digital components disturb analog components, introducing noise into the system causing degradation of the performance or even introducing errors into the functionality of the system. Today, these effects can only be simulated at a very late stage in the design process, causing large design iterations and increased costs if the designers are required to return and make alterations, which may have occurred at a very early stage in the process. This is why the focus of this work is centered on extracting noise coupling simulation models that can be used at a very early design stage such as the behavioral level and then follow the design through the various design stages. To realize this, SystemC is selected as a platform and implementation example for the behavioral level models. SystemC supports design refinement, which means that when designs are being refined and are crossing the design levels, the noise coupling models can also be refined to suit the current design. This new way of thinking in primarily mixed-signal designs is called Behavioral level Noise Coupling (BeNoC) simulation and shows great promise in enabling a reduction in the costs of design iterations due to component cross-talk and simplifies the work for mixed-signal system designers.
Electronics Design Division
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39

Perez, Felix, and Javier Ferrer. "DEVELOPMENT OF AN EMI MEASUREMENT SYSTEM : Performance Analysis of Bluetooth communication under noise environment." Thesis, University of Gävle, Department of Technology and Built Environment, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-721.

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This thesis is a project carried out at the “Centre for RF Measurements Technology of Gävle”. The first aim of this work was basically to develop an EMI measurement system, to that purpose, it has been used an EMI Tester receiver, Spectrum Analyzer and a broadband antenna. Tables and graphics are shown to provide the values of the different detectors utilized.

Using this measurement system, an interference file was recorded and then inserted in a Bluetooth communication model. The interference file was simulated with Matlab Simulink, to check how the interference affected the communication; the effects of the signal degradation are presented in a graphic.

Finally a real Bluetooth communication was established using two Bluetooth modules from Free2Move Company, to prove that the effect of microwave oven interferences produces the increase of transmission time and therefore decrease the Throughput.

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40

Typpö, Jukka. "Noise tolerant voltage-controlled LC oscillator circuits for deep submicron VLSI system-on-a-chip radio circuits." Doctoral thesis, Norwegian University of Science and Technology, Faculty of Information Technology, Mathematics and Electrical Engineering, 2003. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-121.

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This thesis studies the problems with maintaining the spectral purity of fully integrated VCO circuits for radio frequency synthesizers in single-chip system designs. LC tank circuit oscillator circuits are shown to convert amplitude variation in the tank circuit voltage into frequency modulation, if voltage dependent capacitances are present in the tank circuit. Since the parasitic capacitances of the gain transistors and the capacitance of the varactor device in a VCO circuit are voltage dependent, any interfering signal, that is able to modulate the amplitude of the VCO tank circuit voltage waveform, is converted to FM sidebands in the output signal spectrum. It is also shown that the AM-FM conversion may be prohibited under some conditons.

A new method for simulating the steady-state voltage waveform of an LC tank circuit oscillator is presented. In this method, one complete oscillation cycle is simulated piecewise, employing the known solution of the damped harmonic motion equation. The voltage-dependent parameters of the equation are updated in the beginning of each segment. The steady state is found by matching the initial conditions and the final conditions of one complete oscillation cycle, using a numerical optimization algorithm. The method avoids finding the solution of the differential equation with variable coefficients.

For minimizing the sensitivity of integrated VCO circuits to the intra-chip noise sources, this work proposes minimizing the AM-FM conversion by designing the VCO in the way that the voltage dependent capacitances of the oscillator core circuit are made to cancel each other’s effects on the oscillation frequency at some amplitude level. Experimental results demonstrate 15 dB suppression of the sidebands due to the modulated tail current noise in a negative-Gm spiral inductor PFET VCO circuit. The varactorless prototype circuit is implemented in a 0.35 µm CMOS technology. The measured tuning range of the 3 GHz back gate tuned VCO circuit is 10 %, and the current consumption of the core circuit is 2.5 mA. The phase noise level is -110 dBc at 500 kHz offset frequency.

The last part of this thesis discussses the problems with modeling and characterizing small MOS transistors, and presents characterization of 28 µm wide MOSFSET devices. A new method for extracting the drain and source electrode resistances from the measured Z22 response is presented. The response is measured at a constant and very low signal frequency, with Vds = 0 V and with various gate-source bias voltage values. At low signal frequencies, the equivalent diagram of the MOSFET is dramatically simplified, since all parasitic capacitors of the device may be ignored. Consequently, the number of degrees of freedom in the curve fitting is reduced to only two.

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41

Aqeeli, Mohammed Ali M. "Microwave oscillator with phase noise reduction using nanoscale technology for wireless systems." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/microwave-oscillator-with-phase-noise-reduction-using-nanoscale-technology-for-wireless-systems(46287d2a-bc90-4cee-b893-ccf6a3b0747f).html.

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This thesis introduces, for the first time, a novel 4-bit, metal-oxide-metal (MOM) digital capacitor switching array (MOMDCSA) which has been implemented into a wideband CMOS voltage controlled oscillator (VCO) for 5 GHz WiMAX/WLAN applications. The proposed MOMDCSA is added both in series and parallel to nMOS varactors. For further gain linearity, a wider tuning range and minor phase noise variations, this varactor bank is connected in parallel to four nMOS varactor pairs, each of which is biased at a different voltage. Thus, VCO tuning gain reduces and optimal phase noise variation is obtained across a wide range of frequencies. Based on this premise, a wideband VCO is achieved with low phase noise variation of less than 4.7 dBc/Hz. The proposed VCO has been designed using UMC 130 nm CMOS technology. It operates from 3.45 GHz to 6.23 GHz, with a phase noise of -133.80 dBc/Hz at a 1 MHz offset, a figure of merit (FoM) of -203.5 dBc/Hz. A novel microstrip low-phase noise oscillator is based on a left-handed (LH) metamaterial bandpass filter which is embedded in the feedback loop of the oscillator. The oscillator is designed at a complex quality factor Qsc peak frequency, to achieve excellent phase noise performance. At a centre frequency of 2.05 GHz, the reported oscillator demonstrates, experimentally, a phase noise of -126.7 dBc/Hz at a 100 kHz frequency offset and a FoM of -207.2 dBc/Hz at a 1 MHz frequency offset. The increasing demands have been placed on the electromagnetic compatibility performance of VCO devices is crucial. Therefore, this thesis extends the potential of highly flexible and conductive graphene laminate to the application of electromagnetic interference (EMI) shielding. Graphene nanoflake-based conductive ink is printed on paper, and then it is compressed to form graphene laminate with a conductivity of 0.43×105 S/m. Shielding effectiveness is experimentally measured at above 32 dB as being between 12GHz and 18GHz, even though the thickness of the graphene laminate is only 7.7µm. This result demonstrates that graphene has great potential for offering lightweight, low-cost, flexible and environmentally friendly shielding materials which can be extended to offering required shielding from electromagnetic interference (EMI), not only for VCO phase noise optimisation, but also for sensitive electronic devices.
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42

Devarajan, Yamuna Swetha. "Discriminating the Effects of Vineyard Management Practices on Grape and Wine Volatiles from Cabernet Franc and Merlot Grape Varieties Using Electronic Nose Systems." Thesis, Virginia Tech, 2009. http://hdl.handle.net/10919/34688.

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Vineyard management practices are known to affect fruit composition and resultant wines, in part, by altering fruit volatiles. Methods currently used to evaluate the impact of vineyard practices on grape/wine composition include measuring physico-chemistry indices and performing wine sensory analyses. These activities are both time-consuming and destructive. Two electronic nose (ENose) systems: a hand-held conducting polymer-based and a portable surface acoustic wave-based systems were investigated as grape monitoring tools. Vineyard treatments included the effect of canopy side (East vs. West and North vs. South), cluster thinning (unthinned, 1 cluster/shoot, and 1 & 2 cluster/shoot) and ethanol spray (5% v/v) on Cabernet franc, Merlot and both varieties respectively. ENose data were obtained in the field (over two growing seasons for canopy side and in 2008 for cluster thinning and ethanol spray) and laboratory (2007 for canopy side), across different sampling dates and compared with nine-grape/eight-wine chemistry assays, GC/MS (cluster thinning) and wine aroma sensory evaluations (triangular difference testing). ENose results demonstrated 100% significant differences between all Cabernet franc and Merlot treatments. Grape/wine chemistry indices, for both Cabernet franc and Merlot, did not differ among treatments (except ethanol treatment) across sampling dates or growing seasons and vineyard management practices. Wine aroma sensory evaluations demonstrated only limited differences (3 out of 8 comparisons: East vs. West, 1 cluster/shoot vs. 1 & 2 clusters/shoot and 1 cluster/shoot and 1 & 2 clusters/shoot). The high level of discrimination by ENose systems may provide opportunities to enhance the understanding of vineyard management activities.
Master of Science in Life Sciences
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43

Solé, Carbonell Marta. "Statocyst sensory epithelia ultrastructural analysis of Cephalopods exposed to noise." Doctoral thesis, Universitat Politècnica de Catalunya, 2012. http://hdl.handle.net/10803/84184.

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Controlled Exposure Experiments revealed lesions in the statocysts of four cephalopod species of the Mediterranean Sea (Sepia officinalis, Loligo vulgaris, Illex coindetii and Octopus vulgaris), when exposed to relatively low intensity low frequency sounds. The analysis was performed through: scanning (SEM) and transmission (TEM) electron microscopy techniques of the whole inner structure of the cephalopod statocysts, especially on macula and crista; SEM of the epidermal lines of cephalopod hatchlings; and proteomic studies (2DE/MALDI –MS) of the statocyst’s endolymph. All exposed adult individuals presented the same lesions and the same incremental effects over time, consistent with a massive acoustic trauma observed in land species that were exposed to much higher intensities of sound. Immediately after exposure, the damage was observed in the macula statica princeps (msp) and in the crista sensory epithelium. Kinocilia on hair cells were either missing or were bent or flaccid. A number of hair cells showed protruding apical poles and ruptured lateral plasma membranes, most probably resulting from the extrusion of cytoplasmic material. Hair cells were also partially ejected from the sensory epithelium, and spherical holes corresponding to missing hair cells were visible in the epithelium. The cytoplasmic content of the damaged hair cells showed obvious changes, including the presence of numerous vacuoles and electron dense inclusions not seen in the control animals. The appearance of these lesions became gradually more pronounced in individuals after 12, 24, 48, 72, and 96 hours. Special attention was given to validate these findings with control animals that were caught, maintained and sequentially sacrificed following the same protocol as the exposed individuals. The statocyst ultrastructure was therefore revisited and a comparative analysis was carefully conducted to assess the lesions triggered by the exposure to noise This study also presents preliminary results of the sound effects on epidermal lines of cephalopod hatchlings. The lesions, consistent with an acoustic trauma, were identic in the three species that were exposed, but their evolution over time, in opposition with what was observed in the statocysts, were different, suggesting that the animal size and metabolic response might play a role in a possible recovery process. The analysis of noise effects in the statocyst endolymph by proteomic techniques was only conducted on Sepia officinalis. The presence of differential staining of gels from control and subjected to sound exposure individuals demonstrate that the injuries could be related to a possible physiological imbalance that would affect the protein levels of the endolymph. The lesions and findings described here are new to cephalopod pathology. Given that lowfrequency noise levels in the ocean are increasing (e.g. due to shipping, offshore industry, and naval maneuvers), that the role of cephalopods in marine ecosystems is only now beginning to be understood, and that reliable bioacoustic data on invertebrates are scarce, the present study and future investigations will bring an important contribution to the sustainable use of the marine environment.
Després de sotmetre'ls a experiments d'exposició controlada a sons de baixa intensitat i baixa freqüència es van observar lesions en els estatocists de quatre espècies de cefalòpodes de la mar Mediterrània (Sepia officinalis, Loligo vulgaris, Illex coindetii i Octopus vulgaris). L'anàlisi es va realitzar per mitjà de de microscòpia electronica d'escombratge (SEM) i de transmissió (TEM) de tota l'estructura interna de l'estatocist dels cefalòpodes, especialment en la màcula i en la crista, per SEM de les línees epidèrmiques de les larves dels cefalòpodes i per tècniques de proteòmica (2DE/MALDI-MS), de l'endolimfa de l'estatocist. Tots els estatocists d'individus adults de cefalòpodes exposats presentaven les mateixes lesions i aquests efectes eren més greus a mesura que passava el temps després de l'exposició als sons. Tots els animals exposats al soroll van mostrar lesions consistens amb trauma acústic massiu observat en altres espècies terrestres que havien estat exposades a intensitats molt més altes de so. Immediatament després de l'exposició, es van observar danys a la macula statica princeps (msp) i en l'epiteli sensorial de la crista. Els quinocilis de les cèl·lules ciliades desapareixien o es doblegaven i es tornaven flàccids. Un nombre important de cèl·lules ciliades mostraven els pols apicals sobresortint de l'epiteli sensorial, així com el trencament de les membranes plasmàtiques laterals, molt probablement com a resultat de l'extrusió de material citoplasmàtic. Les cèl·lules ciliades també van ser parcialment expulsades de l'epiteli sensorial deixant visibles forats esfèrics en el mateix. El contingut citoplasmàtic de les cèl·lules ciliades danyades va mostrar canvis obvis, com ara la presència de nombrosos vacúols i inclusions electrodenses que no es veien en els animals control. L'aparició d'aquestes lesions es va tornar gradualment més pronunciada en els individus analitzats després de 12, 24, 48, 72 i 96 hores. Es van validar curosament aquests resultats per mitjà de la comparació amb els animals control que van ser capturats, mantinguts i sacrificats de forma seqüencial seguint el mateix protocol que els individus exposats. La ultraestructura de l'estatocist va ser revisada i es va dur a terme un curós anàlisi comparatiu per tal d'avaluar les lesions provocades per l'exposició al soroll. Aquest estudi també presenta els resultats preliminars dels efectes del so en les línies epidèrmiques de cefalòpodes recent nascuts. Les lesions, consistens amb trauma acústic, eren idèntiques en les tres espècies que van ser exposades, però la seva evolució en el temps, en oposició amb el que es va observar en els estatocists, era diferent, cosa que suggereix que la grandària dels animals i la resposta metabòlica podria tenir influència en un possible procés de recuperació. L'avaluació dels efectes en l'endolimfa de l'estatocist per tècniques de proteòmica es va dur a terme només en Sepia officinalis. La presència de taques diferencials en els gels dels individus control i els sotmesos a exposició a so demostren que les lesions podrien estar relacionades amb un possible desequilibri fisiològic que tindria repercusions en els nivells proteics de l'endolimfa. Les lesions descrites aquí són noves pel que fa a la patologia dels cefalòpodes. Atès que els nivells de soroll de baixa freqüència a l'oceà estan augmentant (per exemple, a causa del transport, la indústria petrolera i les maniobres navals), que el paper dels cefalòpodes en els ecosistemes marins només ha començat a ser entès recentment, i que les dades bioacústiques fiables sobre els invertebrats són escasses, el present estudi i les investigacions futures aportaran una important contribució a l'ús sostenible del medi marí.
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44

Mousa, Pasandi Mohammad. "Adaptive decision-directed channel equalization and laser phase noise induced inter-carrier-inteference mitigation for coherent optical orthogonal frequency division multiplexing transport systems." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=114464.

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The explosive growth of global Internet traffic has placed tremendous strain on both op-tical networks and optical transmission systems, underscoring the need for not only high-capacity transmission links but also for flexible, reconfigurable, and adaptive networks. Re-cent progress in complementary metal–oxide–semiconductor (CMOS) technology has fa-cilitated the use of digital signal processing (DSP) in optical communication systems. Blessed with the revival of coherent optical transmission systems, over the past few years, DSP-enabled, software-defined optical transmission (SDOT) systems have led the funda-mental paradigm shift from inflexible optical networks to robust, reconfigurable, plug-and-play optical networks.Recently, coherent optical orthogonal frequency division multiplexing (CO-OFDM) has been intensively investigated as a promising modulation format for realizing coherent transmission systems. Although CO-OFDM has attracted significant interest in the research community, it has yet to leave a tangible impact on the commercial front due to implemen-tation shortcomings, such as excessive overhead, and susceptibility to fibre nonlinearities and frequency/phase noise.This thesis explores DSP-based solutions for CO-OFDM transmission systems, including two key original contributions. The first contribution is a novel adaptive decision-directed channel equalizer (ADDCE) that aims to reduce the required overhead in CO-OFDM transmission systems. ADDCE retrieves an estimation of the phase noise value after an initial decision making stage, by extracting and averaging the phase drift of all OFDM sub-channels, demonstrating zero-overhead phase noise compensation. Moreover, it updates the channel transfer matrix on a symbol-by-symbol basis, thus enabling a reduction in the associated overhead with pilot symbols. The second original contribution of this thesis focuses on the mitigation of the effect of the laser phase noise induced inter-carrier interfer-ence (ICI) in CO-OFDM systems. This interpolation-based ICI compensator estimates the time-domain phase noise samples using linear interpolation between the common-phase-error (CPE) estimates of consecutive OFDM symbols.The performances of the aforementioned DSP equalization schemes are numerically and experimentally studied in reduced-guard-interval dual-polarization CO-OFDM (RGI-DP-CO-OFDM) transmission systems, and are found to demonstrate superior performance over conventional equalizers (CEs). In addition, a computational complexity analysis of the pro-posed equalizers is provided, which confirms a low implementation complexity.
La croissance explosive du trafic globale sur Internet a crée une pression importante sur les réseaux optiques et les systèmes de transmission optiques; ce qui suggère le besoin de liens de transmission de haute capacité ainsi que de réseaux adaptables, reconfigurables et flexible. Les récents progrès dans les technologies de semiconducteurs métal-oxyde com-plémentaire (CMOS) ont facilité l'usage des traitements de signaux numériques (DSP) dans les systèmes de transmission optique. Grâce au retour en force du système de transmission optique cohérent ces dernières années, les systèmes de transmission optique régis par logiciel et supportés par les traitements de signaux numériques ont mené la transition fondamentale des réseaux optique inflexible vers des réseaux optique robuste, reconfigurable, prêt à brancher et utiliser.Depuis peu, le format de modulation par multiplexage fréquentiel orthogonale en optique cohérente (CO-OFDM) est profondément étudier comme format de modulation particu-lièrement prometteur pour réaliser des systèmes de transmission cohérents. Malgré le fait que les CO-OFDM aient réussi à susciter un grand intérêt dans la communauté de recherche, ils leur restent encore à avoir un impact plus tangible dans le secteur commercial. Ce non-déploiement commercial est attribué aux difficultés d'implémentations, notamment à l'information superflue excessive nécessaire et à la susceptibilité accrue aux nonlinéarités de la fibre optique et aux bruits de fréquence et de phase.Cette thèse explore certaines idées de DSP pour des systèmes de transmission CO-OFDM, incluant deux contributions originales. La première étant un égalisateur de canaux à adaptation dirigée par décision (ADDCE) qui vise à réduire l'information superflue nécessaire aux systèmes de transmission CO-OFDM. ADDCE récupère une estimation de la valeur du bruit de phase après un stage initiale de décision en extrayant et en moyennant la dérive de phase de tout les sous-canaux OFDM, ce qui démontre une compensation du bruit de phase sans information superflue. De plus, cela ajourne la matrice de transfère du canal optique symbole par symbole, offrant une réduction de l'information excédante associés avec les symboles pilotes. La seconde contribution de cette thèse se concentre sur la mitiga-tion de l'interférence inter-canaux (ICI) induite par le bruit de phase du laser dans les systèmes CO-OFDM. Ce compensateur de ICI basé sur l'interpolation estime le bruit de phase des échantillons dans le temps en utilisant une interpolation linéaire entre les estimations d'erreur de phase commune (CPE) de symboles OFDM consécutifs. Les performances des algorithmes d'égalisations appliqués en DSP mentionnés ci-haut sont étudiées en simulations et expérimentalement dans un système de transmission en CO-OFDM sur double polarisation à intervalle de garde réduite (RGI-DP-CO-OFDM), ce qui démontre une performance supérieure vis-à-vis de l'égalisateur conventionnel (CEs). Plus encore, l'analyse de la complexité des algorithmes d'égalisateurs proposées sera fournit; confirmant une implémentation à faible complexité.
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45

Guo, Bin. "A bio-inspired electronic nose micro-system based on integrated gas sensor array and log-spike processing /." View abstract or full-text, 2008. http://library.ust.hk/cgi/db/thesis.pl?ECED%202008%20GUO.

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46

Abbati, Luca. "Development of a Bi-Directional Electronics Platform for Advanced Neural Applications." Scholar Commons, 2012. http://scholarcommons.usf.edu/etd/4271.

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This work presents a high-voltage, high-precision bi-directional multi-channel system capable of stimulating neural activity through bi-phasic pulses of amplitude up to ∓50 V while recording very low-voltage responses as low as tens of microvolts. Most of the systems reported from the scientific community possess at least one of the following common limitations: low stimulation voltages, low gain capabilities, or insufficient bandwidth to acquire a wide range of different neural activities. While systems can be found that present remarkable capabilities in one or more specific areas, a versatile system that performs over all these aspects is missing. Moreover, as many novel materials, like silicon carbide, are emerging as biocompatible interfaces, and more specifically as neuronal interfaces, it becomes mandatory to have a system operating across a wide range of voltages and frequencies for both physiological and electrical compatibility testing. The system designed and proven during this doctoral research effort features a ∓50 V bi-phasic pulse generator, 62 to 100 dB of software selectable amplification, and a wide 18 Hz to 12 kHz bandwidth. In addition to design and realization we report about biological testing consisting in the acquisition of neural signals from tissue cultures using an MEA where faithful signal recording was achieved with superior fidelity to a commercial system used to sample signals from the same culture. The only system parameter that was less robust than the commercial system was the noise level, which due to our higher bandwidth was somewhat expected. More importantly our custom electronics outperformed in terms of lower delay and lower cost of realization. All of these results plus suggested future works are listed for the reader's convenience.
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47

Thrivikraman, Tushar. "Analysis and Design of Low-Noise Amplifiers in Silicon-Germanium Hetrojunction Bipolar Technology for Radar and Communication Systems." Thesis, Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/19755.

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This thesis presents an overview of the simulation, design, and measurement of state-of-the-art Silicon-Germanium Hetro-Junction Bipolar Transistor (SiGe HBT) low-noise amplifiers (LNAs). The LNA design trade-off space is presented and methods for achieving an optimized design are discussed. In Chapter 1, we review the importance of LNAs and the benefits of SiGe HBT technology in high frequency amplifier design. Chapter 2 introduces LNA design and basic noise theory. A graphical LNA design approach is presented to aid in understanding of the high-frequency LNA design process. Chapter 3 presents an LNA design optimization method for power constrained applications. Measured results using this design technique are highlighted and shown to have record performance. Lastly, in Chapter 4, we highlight cryogenic noise performance and present measured results from cryogenic operation of SiGe HBT LNAs. We demonstrate in this thesis that SiGe HBT LNAs have the capability to meet the demanding needs for next generation wireless systems. The aim of the analysis presented herein is to provide designers with the fundamentals of designing SiGe HBT LNAs through relevant design examples and measured results.
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48

Charlamov, Jevgenij. "Time domain optical reflectometer systems investigation." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2014. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2013~D_20140227_140438-77567.

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The dissertation investigates the optical time domain reflectometer (OTDR) systems. The main object of research is an optical receiver for OTDR. The aim of the work is to create an optical receiver design method-ology to achieve optimal dynamic range of the system for a given band-width, design and investigate integrated fully differential variable gain tran-simpedance amplifier for OTDR optical receiver. Main tasks solved in this work are: perform analysis of OTDR struc-tures, main specifications and suggest possible improvement approaches; analyze main optical receiver noise sources and noise minimization and create generalized noise model; create optical receiver for an OTDR design methodology, that allow calculating avalanche photodiode multiplication factor, transimpedance amplifier feedback resistance and voltage amplifier input transistor dimensions that achieves optimal OTDR dynamic range; design and perform simulations of transimpedance amplifier integrated cir-cuit using AMS 0.35 µm CMOS technology and calculate optical receiver parameters in 0.1–100 MHz range of bandwidths The dissertation consists of four parts including Introduction, 4 chap-ters, Conclusions, References and 1 Annex. The introduction reveals the investigated problem, importance of the thesis and the object of research. It also describes the purpose and tasks, research methodology, scientific novelty, the practical significance of re-sults examined in the paper and defended statements. The... [to full text]
Disertacijoje nagrinėjamos laiko srities optinės reflektometrinės (OTDR) sistemos. Pagrindinis tyrimo objektas yra OTDR įėjimo pakopa – optinis imtuvas (OI). Disertacijos tikslas – sukurti OI projektavimo metodiką, lei-džiančią pasiekti optimalų dinaminį diapazoną, suprojektuoti ir ištirti integ-rinį diferencinį pereinamos varžos stiprintuvą (PVS) su kintamu stiprinimo koeficientu. Darbe sprendžiami šie uždaviniai: atliekama OTDR ir jų pagrindinių charakteristikų analizė ir formuluojamos tobulinimo kryptys; analizuojami pagrindiniai optinio imtuvo triukšmų šaltiniai, jų mažinimo galimybės ir su-daromas apibendrintas optinio imtuvo triukšmų modelis; sukuriama OI pro-jektavimo metodika, leidžianti apskaičiuoti griūtinio fotodiodo dauginimo faktorių, pereinamosios varžos stiprintuvo grįžtamojo ryšio varžą ir įėjimo tranzistoriaus fizinius matmenis, kuriems esant gaunamas optimalus dina-minis diapazonas; projektuojamas optinio imtuvo maketas iš diskrečiųjų elementų ir tiriami jo parametrai; atliekamas integrinio PVS projektavimas ir modeliavimas, taikant 0,35 µm KMOP technologiją bei optinio imtuvo pa-rametrų skaičiavimas 0,1–100 MHz dažnių juostų diapazone. Disertaciją sudaro įvadas ir keturi skyriai. Pabaigoje pateikiami naudo-tos literatūros ir autoriaus publikacijų disertacijos tema sąrašai ir 1 priedas. Įvadiniame skyriuje aptariama: tiriamoji problema, darbo aktualumas, aprašomas tyrimų objektas, suformuluotas darbo tikslas bei uždaviniai, ap-rašoma tyrimų metodika... [toliau žr. visą tekstą]
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49

Gardner, Denise M. "Characterization of Cold Soak on Vitis vinifera L. cv. Cabernet Sauvignon Grape and Wine Volatiles Using an Electronic Nose System." Thesis, Virginia Tech, 2009. http://hdl.handle.net/10919/32708.

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The use of the electronic nose in the wine industry is an emerging technology. Although electronic nose systems have been used in other industries as tools to monitor fruit maturity or quality control, the use of these systems for wine analysis has been debated. Many electronic nose sensor types exist, but have often been accused of primarily discriminating varying ethanol concentrations of wines as opposed to aroma and flavor volatiles. This study evaluated the use of a commercial conducting polymer electronic nose to evaluate wines while minimizing ethanol interference. The first study presented evaluated the discrimination ability of an electronic nose with use of an ethanol baseline prior to wine evaluation. This experiment also determined the optimal wine temperature for electronic nose analysis. A second study reviewed the ability of the electronic nose to discriminate Cabernet Sauvignon grape and wine volatiles based on a pre-fermentation cold soak treatment. The electronic nose was used to monitor volatile changes throughout a five day cold soak, and to discriminate differences in control versus cold soak wines. These results were compared with juice and wine analytical data, GC-MS evaluation of individual volatiles, and sensory analysis of the finished wines. It was found that discrimination of wines improved from 33% to 60% when using an ethanol baseline. Influence of the baseline was indicated by a drop in sensor response prior to wine evaluation. A 30°C sample temperature was chosen for wine analysis based on sensor response and adequate discrimination in canonical distributions. The electronic nose was found to discriminate grape volatiles in cold soak musts as shown in canonical distributions at a 95% significance level. PCA distributions of electronic nose data, chemistry data, and GC-MS data showed varying degrees of discrimination based on analysis. Electronic nose data often showed 100% of variation of samples accounted by PC1. Despite differences in treatment by ENose and analytical data, sensory results did not find a difference in control and cold soak wines.
Master of Science
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50

Xiong, Zhijie. "Radio Frequency Low Noise and High Q Integrated Filters in Digital CMOS Processes." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/5043.

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Radio Frequency Low Noise and High Q Integrated Filters in Digital CMOS Processes Zhijie Xiong 149 pages Directed by Dr. Phillip E. Allen Presented in this work is a novel design technique for CMOS integration of RF high Q integrated filters using positive feedback and current mode approach. Two circuits are designed in this work: a 100MHz low-noise and high Q bandpass filter suited for an FM radio front-end, and a 2.4GHz low-noise and high-Q bandpass filter suited for a Bluetooth front-end. Current-mode approach and positive feedback design techniques are successfully used in the design of both circuits. Both circuits are fabricated through a 0.18um CMOS process provided by National Semiconductor Corp. The 100MHz circuit achieves 3.15uV RF sensitivity with 26dB SNR, and the total current consumption is 12mA. The center frequency of the filter is tunable from 80MHz to 110MHz, and the Q value is tunable from 0.5 to 28.9. 1 dB compression point is measured as -34.0dBm, combined with noise measurement results, a dynamic range of 54.1 dB results. Silicon area of the core circuit is 0.4 square millimeters. The center frequency of the 2.4GHz circuit is tunable from 2.4GHz to 2.5GHz, and the Q value is tunable from 20 to 120. The 1 dB compression dynamic range of the circuit is 50dB. Integrated spiral inductors are developed for this design. Patterned ground shields are laid out to reduce inductor loss through substrate, especially eddy current loss when the circuit is fabricated on epi wafers. Accumulation mode MOS varactors are designed to tune the frequency response. Silicon area of the core circuit is 1 square millimeter.
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