Mixed-signal designs are becoming more and more complex every day. In order to adapt to the new market requirements, a formal process for design and verification of mixed signal systems i. e. top-down design and bottom-up verification methodology is required. This methodology has already been established for digital design. The goal of this research is to propose a new design methodology for mixed signal systems. In the first two chapters of this thesis, the need for a mixed signal design flow based on top-down design methodology will be discussed. The proposed design flow is based on behavioral modeling of the mixed signal system using one of the mixed signal behavioral modeling languages. These models can be used for design and verification through different steps of the design from system level modeling to final physical design. The other advantage of the proposed flow is analog and digital co-design. In the remaining chapters of this thesis, the proposed design flow was verified by designing an 800 MHz mixed signal PLL. The PLL uses a charge pump phase frequency detector, a single capacitor loop filter, and a feed forward error correction architecture using an active damping control circuit instead of passive resistor in loop filter. The design was done in 0. 18- <i>??</i> m CMOS process technology.

In aposematism a prey species use bright colours, often combined with a black contrasting pattern, to signal unprofitability as prey to potential predators. Although there are several different hypotheses about the presence of these internally contrasting patterns, there is little experimental evidence of any beneficial effects. In this thesis I have used bird predators and artificial prey signals to investigate if the contrasting internal patterns in warning displays may have evolved to increase signal efficacy, especially regarding the speed of avoidance learning. In paper I the relative importance of colour and pattern in avoidance learning was studied. The conclusion was that birds primarily attend to colour, not pattern, when learning the discrimination, which was further supported by the results in paper II-IV, all suggesting a secondary role of patterns. In paper II I show that predators may to some degree use patterns for discrimination, if they convey important information about prey quality. The predators showed a hierarchical way of learning warning colour components, where colour is learned to a higher degree than pattern. In paper III I investigate if internal contrasting patterns promote avoidance learning by increasing conspicuousness as prey-to-background contrast does. The study did not support this idea, as the presence of internal black patterns did not improve avoidance learning on a colour matching background. In paper IV, however, I show that the presence of many internal colour boundaries resulted in faster avoidance learning on a multi-coloured background, and predator generalization favoured more internal boundaries, while there was no effect of pattern regularity. From these studies I conclude that internal pattern contrasts may function to increase the efficacy of the warning colour, its salience, and as a means for aposematic prey to be discriminated from harmful mimics. However, the major finding is the importance of colour over pattern. / <strong><em></em></strong><em></em><em></em>At  the time of the doctoral defence the following papers were unpublished and had a status as follows: Paper 2: Manuscript; Paper 4: Manuscript<strong><em> </em></strong>

The miniaturization and digitization of modern microelectronic systems have made Analog-to-Digital converters (ADC) key building components in many applications. Internet and entertainment technologies demand higher and higher performance from the hardware components in many communication and multimedia systems, but at the same time increased mobility demands less and less power consumption. Many applications, such as instrumentation, video, radar and communications, require very high accuracy and speed and with resolutions up to 16 bits and sampling rates in the 100s of MHz, pipelined ADCs are very suitable for such purposes. Resolutions above 10 bits often require very high power consumption and silicon area if no error correction technique is employed. Calibration relaxes the accuracy requirement of the individual building blocks of the ADC and enables power and area savings. Digital calibration is preferred over analog calibration due to higher robustness and accuracy. Furthermore, the microprocessors that process the digital information from the ADCs have constantly reduced cost and power consumption and improved performance due to technology scaling and innovative microprocessor architectures. The work in this dissertation presents a novel digital background calibration technique for high-speed, high-resolution pipelined ADCs. The technique is implemented in a 14 bit, 100 MS/s pipelined ADC fabricated in Taiwan Semiconductor Manufacturing Company (TSMC) 0.13µm Complementary Metal Oxide Semiconductor (CMOS) digital technology. The prototype ADC achieves better than 11.5 bits linearity at 100 MS/s and achieves a best-in-class figure of merit of 360 fJ/conversion-step. The core ADC has a power consumption of 105 mW and occupies an active area of 1.25 mm^2. The work in this dissertation also presents a low-power, 8-bit algorithmic ADC. This ADC reduces power consumption at system level by minimizing voltage reference generation and ADC input capacitance. This ADC is implemented in International Business Machines Corporation (IBM) 90nm digital CMOS technology and achieves around 7.5 bits linearity at 0.25 MS/s with a power consumption of 300 µW and an active area of 0.27 mm^2.

Mixed-signal designs are becoming more and more complex every day. In order to adapt to the new market requirements, a formal process for design and verification of mixed signal systems i. e. top-down design and bottom-up verification methodology is required. This methodology has already been established for digital design. The goal of this research is to propose a new design methodology for mixed signal systems. In the first two chapters of this thesis, the need for a mixed signal design flow based on top-down design methodology will be discussed. The proposed design flow is based on behavioral modeling of the mixed signal system using one of the mixed signal behavioral modeling languages. These models can be used for design and verification through different steps of the design from system level modeling to final physical design. The other advantage of the proposed flow is analog and digital co-design. In the remaining chapters of this thesis, the proposed design flow was verified by designing an 800 MHz mixed signal PLL. The PLL uses a charge pump phase frequency detector, a single capacitor loop filter, and a feed forward error correction architecture using an active damping control circuit instead of passive resistor in loop filter. The design was done in 0. 18- <i>µ</i> m CMOS process technology.

No description available.

No description available.

Este trabalho descreve o desenvolvimento de um algoritmo para avaliar o grau de corrosão em paredes de oleodutos, através de ultrassom. O algoritmo desenvolvido será implementado em um circuito digital, fazendo parte de um sistema que poderá ser embarcado em pigs ultrassônicos para inspeção de dutos à procura de corrosão. O modelo matemático conhecido como filtro casado é usado como base do algoritmo, além de um método de detecção de picos para localização dos sinais de eco de ultrassom, provenientes das reflexões do sinal nas paredes dos dutos. Um dos problemas é a definição do sinal (e do filtro) que será utilizado, mas por meio de sinais sintetizados (signal design) uma grande gama de alternativas foi analisada e apenas algumas foram selecionadas para testes em experimentos. Por último os melhores sinais foram utilizados na inspeção de um corpo de prova feito à partir de um duto corroído, e os resultados são analisados. A detecção da primeira parede do oleoduto apresenta resultados promissores em comparação com a medição tridimensional das mesmas paredes. O sistema foi capaz de reconstruir o perfil da parede interna do duto com elevada verossimilhança, mesmo em regiões severamente corroídas. A detecção da segunda parede apresenta resultados satisfatórios para baixos níveis de corrosão, porém alguns problemas foram encontrados para níveis mais altos de corrosão, prejudicando a medição direta da espessura da parede nestas condições. / This work describes the development of an algorithm to evaluate the degree of corrosion in pipeline walls, using ultrasound. The developed algorithm will be implemented in a dedicated digital circuit that can be embedded in ultrasonic pigs for pipeline corrosion inspection. The algorithm is based on the mathematic model known as matched filter, besides a peak detection method for the location of ultrasound echoes, originated from the signal reflections in the pipeline walls. One problem is the determination of the signal (and filter) that should be used, but using a signal design approach a large number of possibilities could be analyzed and only a few was tested in experiments. Finally, the best signals were used to inspect a test specimen made of a corroded pipeline section, and the results were analyzed. The first wall detection shows promising results when compared to the results of a three-dimensional inspection of the same walls. It was possible to reconstruct the profile of the internal wall with good likelihood, even at badly corroded areas. The second wall detection shows some satisfactory results on low corrosion levels, but show some problems with high corrosion levels, compromising the direct measurement of the wall of the pipeline.

Este trabalho descreve o desenvolvimento de um algoritmo para avaliar o grau de corrosão em paredes de oleodutos, através de ultrassom. O algoritmo desenvolvido será implementado em um circuito digital, fazendo parte de um sistema que poderá ser embarcado em pigs ultrassônicos para inspeção de dutos à procura de corrosão. O modelo matemático conhecido como filtro casado é usado como base do algoritmo, além de um método de detecção de picos para localização dos sinais de eco de ultrassom, provenientes das reflexões do sinal nas paredes dos dutos. Um dos problemas é a definição do sinal (e do filtro) que será utilizado, mas por meio de sinais sintetizados (signal design) uma grande gama de alternativas foi analisada e apenas algumas foram selecionadas para testes em experimentos. Por último os melhores sinais foram utilizados na inspeção de um corpo de prova feito à partir de um duto corroído, e os resultados são analisados. A detecção da primeira parede do oleoduto apresenta resultados promissores em comparação com a medição tridimensional das mesmas paredes. O sistema foi capaz de reconstruir o perfil da parede interna do duto com elevada verossimilhança, mesmo em regiões severamente corroídas. A detecção da segunda parede apresenta resultados satisfatórios para baixos níveis de corrosão, porém alguns problemas foram encontrados para níveis mais altos de corrosão, prejudicando a medição direta da espessura da parede nestas condições. / This work describes the development of an algorithm to evaluate the degree of corrosion in pipeline walls, using ultrasound. The developed algorithm will be implemented in a dedicated digital circuit that can be embedded in ultrasonic pigs for pipeline corrosion inspection. The algorithm is based on the mathematic model known as matched filter, besides a peak detection method for the location of ultrasound echoes, originated from the signal reflections in the pipeline walls. One problem is the determination of the signal (and filter) that should be used, but using a signal design approach a large number of possibilities could be analyzed and only a few was tested in experiments. Finally, the best signals were used to inspect a test specimen made of a corroded pipeline section, and the results were analyzed. The first wall detection shows promising results when compared to the results of a three-dimensional inspection of the same walls. It was possible to reconstruct the profile of the internal wall with good likelihood, even at badly corroded areas. The second wall detection shows some satisfactory results on low corrosion levels, but show some problems with high corrosion levels, compromising the direct measurement of the wall of the pipeline.

Data transfer rates of communication systems continue to rise fueled by aggressive demand for voice, video and Internet data. Device scaling enabled by modern lithography has paved way for System-on-Chip solutions integrating compute intensive digital signal processing. This trend coupled with demand for low power, battery-operated consumer devices offers extensive research opportunities in analog and mixed-signal designs that enable modern communication systems. The first part of the research deals with broadband wireless receivers. With an objective to gain insight, we quantify the impact of undesired out-band blockers on analog baseband in a broadband radio. We present a systematic evaluation of the dynamic range requirements at the baseband and A/D conversion boundary. A prototype UHF receiver designed using RFCMOS 0.18[mu]m technology to support this research integrates a hybrid continuous- and discrete-time analog baseband along with the RF front-end. The chip consumes 120mW from a 1.8V/2.5V dual supply and achieves a noise figure of 7.9dB, an IIP3 of -8dBm (+2dbm) at maximum gain (at 9dB RF attenuation). High linearity active RC filters are indispensable in wireless radios. A novel feed-forward OTA applicable to active RC filters in analog baseband is presented. Simulation results from the chip prototype designed in RFCMOS 0.18[mu]m technology show an improvement in the out-band linearity performance that translates to increased dynamic range in the presence of strong adjacent blockers. The second part of the research presents an adaptive clock-recovery system suitable for high-speed wireline transceivers. The main objective is to improve the jitter-tracking and jitter-filtering trade-off in serial link clock-recovery applications. A digital state-machine that enables the proposed mixed-signal adaptation solution to achieve this objective is presented. The advantages of the proposed mixed-signal solution operating at 10Gb/s are supported by experimental results from the prototype in RFCMOS 0.18[mu]m technology.

abstract: Increasing interest in individualized treatment strategies for prevention and treatment of health disorders has created a new application domain for dynamic modeling and control. Standard population-level clinical trials, while useful, are not the most suitable vehicle for understanding the dynamics of dosage changes to patient response. A secondary analysis of intensive longitudinal data from a naltrexone intervention for fibromyalgia examined in this dissertation shows the promise of system identification and control. This includes datacentric identification methods such as Model-on-Demand, which are attractive techniques for estimating nonlinear dynamical systems from noisy data. These methods rely on generating a local function approximation using a database of regressors at the current operating point, with this process repeated at every new operating condition. This dissertation examines generating input signals for data-centric system identification by developing a novel framework of geometric distribution of regressors and time-indexed output points, in the finite dimensional space, to generate sufficient support for the estimator. The input signals are generated while imposing &ldquo;patient-friendly&rdquo; constraints on the design as a means to operationalize single-subject clinical trials. These optimization-based problem formulations are examined for linear time-invariant systems and block-structured Hammerstein systems, and the results are contrasted with alternative designs based on Weyl's criterion. Numerical solution to the resulting nonconvex optimization problems is proposed through semidefinite programming approaches for polynomial optimization and nonlinear programming methods. It is shown that useful bounds on the objective function can be calculated through relaxation procedures, and that the data-centric formulations are amenable to sparse polynomial optimization. In addition, input design formulations are formulated for achieving a desired output and specified input spectrum. Numerical examples illustrate the benefits of the input signal design formulations including an example of a hypothetical clinical trial using the drug gabapentin. In the final part of the dissertation, the mixed logical dynamical framework for hybrid model predictive control is extended to incorporate a switching time strategy, where decisions are made at some integer multiple of the sample time, and manipulation of only one input at a given sample time among multiple inputs. These are considerations important for clinical use of the algorithm. / Dissertation/Thesis / Ph.D. Electrical Engineering 2014