Thesis--Auburn University, 2006. / Abstract. Includes bibliographic references (p.78-80).

Performances of multimedia works are hampered by the difficulty of controlling large numbers of incandescent lamps rapidly and accurately. The instrument described in this document is aimed at alleviating this problem. Chapter I describes the design and operation of the voltage-controlled dimmer unit and the DC controller. Chapter II describes step-by-step procedures for building the instrument. Schematics, wiring diagrams, and illustrative photographs are included. Chapter III discusses some of the aesthetics and philosophy of multimedia composition, and then describes various scenarios which utilize the instrument. Included are the connection of peripheral control equipment, audio/Video interfacing, and the potential for constructing prepared tapes which will automatically drive the dimmers. The prototype was built at the NTSU Electronic Music Center.

Liquid crystal (LC) devices can be operated as amplitude modulators and phase modulators. LC amplitude modulation is commonly used in liquid crystal display (LCD) while phase-only modulation is useful for laser beam steering, tunable grating, prism, lens, and other photonic devices. Most LC devices are polarization dependent and require at least one polarizer. As a result, the optical efficiency is low. To enhance display brightness, a power hungry backlight has to be used leading to a high power consumption and short battery life. In a LC phase modulator, the polarization dependent property complicates the laser beam steering system. It is highly desirable to develop new operating mechanisms that are independent of the incident light polarization. In this dissertation, we have developed eight polarization-independent liquid crystal operation principles: three of them are aimed for displays and the other five are for phase modulators. For amplitude modulations, a new polymer-dispersed liquid crystal (PDLC) and two new dye-doped LC gels are polarizer-free by combining light scattering with dye-absorption effects. In phase modulation, we explore five device concepts: PDLC and Polymer-Stabilized Cholesteric Texture (PSCT), homeotropic LC gels, thin polymer film separated double-layered structure, and double-layered LC gels. In the low voltage regime, both PDLC and PSCT have a strong light scattering. However, as the voltage exceeds a certain level, the phase modulation is scattering-free and is independent of polarization. The homeotropic LC gels do not require any biased voltage and the response time is still fast. Although the remaining phase in these devices is small, they are still useful for micro-photonic device applications. To increase the phase change, thin polymer film separated double-layered structure is a solution. The orthogonal arrangement of top and bottom LC directors results in polarization independence. However, the response time is slow. Similarly, double-layered LC gels are not only polarization independent but also fast response due to the established polymer network.

Leung Hok Sum. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 128-147). / Abstracts in English and Chinese. / Declaration --- p.i / Acknowledgements --- p.ii / Abbreviation --- p.iii / Abstract in English --- p.iv / Abstract in Chinese --- p.vi / Contents --- p.viii / Chapter Chapter I - --- Introduction / Chapter 1.1. --- Steroid Hormone --- p.1 / Chapter 1.2. --- Estrogen Receptors --- p.2 / Chapter 1.3. --- Selective Estrogen Receptor Modulators --- p.5 / Chapter 1.3.1. --- Tamoxifen --- p.5 / Chapter 1.3.1.1. --- Cardiovascular Effects of Tamoxifen --- p.6 / Chapter 1.3.1.2. --- Acute Vascular Effects of Tamoxifen --- p.6 / Chapter 1.3.1.3. --- Chronic Vascular Effects of Tamoxifen --- p.7 / Chapter 1.3.1.4. --- Antioxidant Effects of Tamoxifen --- p.8 / Chapter 1.3.2. --- Raloxifene --- p.8 / Chapter 1.3.2.1. --- Cardiovascular Effects of Raloxifene --- p.8 / Chapter 1.3.2.2. --- Acute Vascular Effects of Raloxifene --- p.9 / Chapter 1.3.2.3. --- Chronic Vascular Effects of Raloxifene --- p.10 / Chapter 1.3.2.4. --- Ovariectomy and Raloxifene Treatment --- p.11 / Chapter 1.4. --- Mechanism of Action of SERMs --- p.15 / Chapter 1.5. --- Effects of Functional Endothelium and Nitric Oxide --- p.18 / Chapter 1.6. --- Dihydropyridine (DHP) Calcium Channel Antagonists --- p.19 / Chapter 1.6.1. --- Development of Newer Generation of Dihydropyridines --- p.19 / Chapter 1.6.2. --- Effects of Dihydropyridines on Vascular Endothelium (I) --- p.20 / Chapter 1.6.3. --- Effects of Dihydropyridines on Vascular Endothelium (II) --- p.21 / Chapter 1.6.4. --- Effects of Dihydropyridines on Nitric Oxide Synthase (NOS) --- p.21 / Chapter 1.6.5. --- Clinical Studies of Dihydropyridines --- p.22 / Chapter 1.7. --- Vascular Ion Channels --- p.25 / Chapter 1.8. --- Objectives of The Present Study --- p.26 / Chapter Chapter II - --- Materials and Methods / Chapter 2.1. --- Tissue Preparation --- p.27 / Chapter 2.1.1. --- Preparation of The Porcine Left Circumflex Coronary Arteries --- p.27 / Chapter 2.1.2. --- Removal of Functional Endothelium --- p.27 / Chapter 2.1.3. --- Organ Bath Setup --- p.27 / Chapter 2.1.4. --- Isometric Force Measurement --- p.29 / Chapter 2.2. --- In situ Endothelial [Ca2+]i Imaging --- p.29 / Chapter 2.2.1. --- Preparation of Porcine Left Circumflex Coronary Arteries --- p.29 / Chapter 2.2.2. --- Setup For In situ Endothelial [Ca2+]i Imaging --- p.30 / Chapter 2.3. --- Electrophysiological Measurement of BKCa Current --- p.31 / Chapter 2.3.1. --- Enzymatic Dissociation of Coronary Artery Smooth Muscle Cells --- p.31 / Chapter 2.3.2. --- Electrophysiological Measurement --- p.31 / Chapter 2.4. --- DPPH Free Radical Scavenging Assay --- p.31 / Chapter 2.5. --- Solutions and Drugs --- p.32 / Chapter 2.5.1. --- "Drugs, Chemicals and Enzymes" --- p.32 / Chapter 2.5.2. --- Solutions Used in Force Measurement --- p.34 / Chapter 2.6. --- Statistical Analysis --- p.34 / Chapter Chapter III - --- Tamoxifen-Induced Endothelial Nitric Oxide-Dependent Relaxation in Porcine Coronary Arteries via Ouabain- and BaCl2-Sensitive Mechanisms / Chapter 3.1. --- Abstract --- p.35 / Chapter 3.2. --- Introduction --- p.36 / Chapter 3.3. --- Methods and Materials --- p.37 / Chapter 3.3.1. --- Vessel Preparation --- p.37 / Chapter 3.3.2. --- Isometric Force Measurement --- p.38 / Chapter 3.3.3. --- In situ Endothelial [Ca2+]i Imaging --- p.39 / Chapter 3.3.4. --- Chemicals --- p.40 / Chapter 3.3.5. --- Data Analysis --- p.40 / Chapter 3.4. --- Results --- p.41 / Chapter 3.4.1. --- Relaxant Responses --- p.41 / Chapter 3.4.2. --- Effects of Inhibitors of NO-Dependent Relaxation --- p.41 / Chapter 3.4.3. --- Effects of Putative K+ Channel Blockers and Ouabain --- p.41 / Chapter 3.4.4. --- "Effects of Ouabain, Removal of Extracellular K+ Ions and BaCI2" --- p.42 / Chapter 3.4.5. --- SNP-Induced Relaxation --- p.42 / Chapter 3.4.6. --- Effects of Actinomycin D and Cycloheximide --- p.42 / Chapter 3.4.7. --- Relaxant Effect of 17β-Estradiol --- p.43 / Chapter 3.4.8. --- Effects on Endothelial [Ca2+]i in Isolated Coronary Arteries With Endothelium --- p.43 / Chapter 3.5. --- Discussion --- p.53 / Chapter Chapter IV - --- Endothelium-Independent Relaxation to Raloxifene in Porcine Coronary Arteries / Chapter 4.1. --- Abstract --- p.57 / Chapter 4.2. --- Introduction --- p.58 / Chapter 4.3. --- Methods and Materials --- p.59 / Chapter 4.3.1. --- Vessel Preparation --- p.59 / Chapter 4.3.2. --- Isometric Force Measurement --- p.60 / Chapter 4.3.3. --- Electrophysiological Measurement of BKCa Current --- p.61 / Chapter 4.3.3.1. --- Enzymatic Dissociation of Coronary Artery Smooth Muscle --- p.61 / Chapter 4.3.3.2. --- Electrophysiological Measurement --- p.62 / Chapter 4.3.4. --- Chemicals --- p.63 / Chapter 4.3.5. --- Data Analysis --- p.63 / Chapter 4.4. --- Results --- p.64 / Chapter 4.4.1. --- Effect of Raloxifene on Agonist-Induced Contractions --- p.64 / Chapter 4.4.2. --- Role of Endothelium --- p.64 / Chapter 4.4.3. --- Effect of ER Antagonist --- p.65 / Chapter 4.4.4. --- Effect of Putative K+ Channel Blockers --- p.65 / Chapter 4.4.5. --- Effect of Elevated Extracellular K+ Concentrations --- p.65 / Chapter 4.4.6. --- Effects of Raloxifene on BKCa Current --- p.65 / Chapter 4.5. --- Discussion --- p.75 / Chapter Chapter V - --- Therapeutic Concentrations of Raloxifene Augment Bradykinin Mediated Nitric Oxide-Dependent Relaxation in Porcine Coronary Arteries / Chapter 5.1. --- Abstract --- p.78 / Chapter 5.2. --- Introduction --- p.79 / Chapter 5.3. --- Methods and Materials --- p.80 / Chapter 5.3.1. --- Vessel Preparation --- p.80 / Chapter 5.3.2. --- Isometric Force Measurement --- p.80 / Chapter 5.3.3. --- In situ Endothelial [Ca2+]i Imaging --- p.81 / Chapter 5.3.4. --- Free Radical Scavenging Assay --- p.82 / Chapter 5.3.5. --- Chemicals --- p.83 / Chapter 5.3.6. --- Data Analysis --- p.83 / Chapter 5.4. --- Results --- p.84 / Chapter 5.4.1. --- Relaxation to Bradykinin --- p.84 / Chapter 5.4.2. --- Effect of Raloxifene on Bradykinin-Induced Relaxation --- p.84 / Chapter 5.4.3. --- Effect of Raloxifene on Relaxation Induced by Substance P and --- p.85 / Chapter 5.4.4. --- Effect of Estrogen on Bradykinin-Induced Relaxation --- p.85 / Chapter 5.4.5. --- Effect of Raloxifene on Sodium Nitroprusside-Induced Relaxation --- p.86 / Chapter 5.4.6. --- Free Radical Scavenging Effect --- p.86 / Chapter 5.4.7. --- Raloxifene Augmentation of Bradykinin-Stimulated Endothelial [Ca2+]i --- p.86 / Chapter 5.5. --- Discussion --- p.99 / Chapter Chapter VI - --- "Cilnidipine, a Slow-Acting Ca2+ Channel Blocker, Induces Relaxation in Porcine Coronary Arteries: Role of Endothelial Nitric Oxide and [Ca2+]i" / Chapter 6.1. --- Abstract --- p.102 / Chapter 6.2. --- Introduction --- p.103 / Chapter 6.3. --- Methods and Materials --- p.104 / Chapter 6.3.1. --- Vessel Preparation --- p.104 / Chapter 6.3.2. --- Isometric Force Measurement --- p.105 / Chapter 6.3.3. --- In situ Endothelial [Ca2+]i Imaging --- p.106 / Chapter 6.3.4. --- Free Radical Scavenging Assay --- p.107 / Chapter 6.3.5. --- Chemicals --- p.108 / Chapter 6.3.6 --- Data Analysis --- p.108 / Chapter 6.4. --- Results --- p.108 / Chapter 6.4.1. --- Relaxant Responses --- p.108 / Chapter 6.4.2. --- Role of the Endothelium --- p.109 / Chapter 6.4.3. --- Effect of Inhibitors of NO-Dependent Relaxation --- p.109 / Chapter 6.4.4. --- Effect of Indomethacin and w-conotoxin --- p.110 / Chapter 6.4.5. --- Effect of Cilnidipine on Sodium Nitroprusside-Induced Relaxation --- p.110 / Chapter 6.4.6. --- Effects on Endothelial [Ca2+]i in Isolated Endothelium-Intact Coronary Arteries --- p.110 / Chapter 6.4.7. --- Free Radical Scavenging Effect --- p.110 / Chapter 6.5. --- Discussion --- p.120 / Chapter Chapter VII - --- General Summary --- p.123 / References --- p.128

published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy

by Cheng Wang-tung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 97-99). / Abstracts in English and Chinese. / Abstract --- p.i / 摘要 --- p.i / Acknowledgements --- p.ii / Table of Contents --- p.iii / List of Figures --- p.vii / List of Tables --- p.xi / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Motivations --- p.1 / Chapter 1.2 --- Objective --- p.4 / Chapter 1.3 --- Outline --- p.4 / Chapter Chapter 2 --- Quadrature ΣΔ Modulator for A/D Conversion --- p.5 / Chapter 2.1 --- Introduction --- p.5 / Chapter 2.2 --- Oversampling ΣΔ Converter --- p.6 / Chapter 2.3 --- Theory of ΣΔ modulation --- p.6 / Chapter 2.3.1 --- Quantization noise --- p.7 / Chapter 2.3.2 --- Oversampling --- p.8 / Chapter 2.3.3 --- Noise Shaping --- p.9 / Chapter 2.3.4 --- Performance Parameter --- p.11 / Chapter 2.3.5 --- Circuit Design of ΣΔ modulator --- p.11 / Chapter 2.3.6 --- Case Study --- p.12 / Chapter 2.3.6.1 --- Transfer Function --- p.12 / Chapter 2.3.6.2 --- Noise Analysis of First Order ΣΔ Modulator --- p.13 / Chapter 2.3.6.3 --- Circuit Level Implementation: --- p.14 / Chapter 2.4 --- Choice of Architecture: Lowpass or Bandpass? --- p.15 / Chapter 2.5 --- I/Q Modulation and Image Rejection --- p.18 / Chapter 2.5.1 --- Quadrature signal --- p.18 / Chapter 2.5.2 --- I/Q Modulation --- p.19 / Chapter 2.6 --- Image Rejection in SC ΣΔ Complex Topology --- p.21 / Chapter 2.6.1 --- High Level Simulation --- p.23 / Chapter 2.6.2 --- Discussion --- p.26 / Chapter 2.7 --- Summary --- p.27 / Chapter Chapter 3 --- Capacitor Sharing Architecture --- p.28 / Chapter 3.1 --- Introduction --- p.28 / Chapter 3.2 --- Proposed mismatch free SC complex ΣΔ Modulator --- p.28 / Chapter 3.2.1 --- Principle of Operation --- p.30 / Chapter 3.3 --- Justification of the Proposed Idea --- p.35 / Chapter 3.4 --- Summary --- p.37 / Chapter Chapter 4 --- Transistor Level Circuit Design --- p.39 / Chapter 4.1 --- Introduction --- p.39 / Chapter 4.2 --- Design of ΣΔ Modulator --- p.39 / Chapter 4.2.1 --- Specification of ΣΔ Modulator --- p.40 / Chapter 4.3 --- Design of Operational Amplifier --- p.45 / Chapter 4.3.1 --- Folded-cascode Operational Amplifier --- p.45 / Chapter 4.3.2 --- Common Mode feedback --- p.47 / Chapter 4.3.3 --- Bias Circuit --- p.49 / Chapter 4.3.4 --- Simulation Results --- p.50 / Chapter 4.4 --- Design of Comparator --- p.54 / Chapter 4.4.1 --- Regenerative Feedback Comparator --- p.54 / Chapter 4.4.2 --- Simulation Results --- p.55 / Chapter 4.5 --- Design of Clock Generator --- p.56 / Chapter 4.5.1 --- Non-Overlapping clock generation --- p.57 / Chapter 4.5.2 --- Simulation Results --- p.58 / Chapter 4.6 --- Simulation Results of ΣΔ Modulator --- p.59 / Chapter 4.7 --- Simulation Results --- p.61 / Chapter 4.7.1 --- Proposed Architecture --- p.62 / Chapter 4.7.2 --- Traditional Architecture --- p.62 / Chapter 4.8 --- Summary --- p.63 / Chapter Chapter 5 --- Layout Considerations and Post-Layout Simulation --- p.65 / Chapter 5.1 --- Introduction --- p.65 / Chapter 5.2 --- Common-Centroid Structure --- p.65 / Chapter 5.3 --- Shielding Technique --- p.67 / Chapter 5.3.1 --- Shielding of device by substrate --- p.67 / Chapter 5.3.2 --- Floor Planning --- p.68 / Chapter 5.4 --- Layout of Power Rail --- p.69 / Chapter 5.5 --- Layout and Post-Layout Simulation of OpAmp --- p.70 / Chapter 5.6 --- Layout and Post-Layout Simulation --- p.74 / Chapter 5.6.1 --- Proposed Architecture --- p.75 / Chapter 5.6.2 --- Traditional Architecture --- p.77 / Chapter 5.7 --- Summary --- p.79 / Chapter Chapter 6 --- Measurement Results --- p.81 / Chapter 6.1 --- Introduction --- p.81 / Chapter 6.2 --- Considerations of PCB Design --- p.82 / Chapter 6.3 --- Measurement Setup --- p.83 / Chapter 6.4 --- Measurement Results --- p.85 / Chapter 6.4.1 --- Measurement Results of Proposed Architecture --- p.85 / Chapter 6.5 --- Summary --- p.92 / Chapter Chapter 7 --- Conclusion --- p.95 / Chapter 7.1 --- Conclusion --- p.95 / Chapter 7.2 --- Future Works --- p.96 / References --- p.97 / Appendix --- p.100 / Chapter A.1 --- Publications --- p.100 / Chapter A.2 --- Schematic of proposed front end --- p.101 / Chapter A.3 --- Schematic of SC ΣΔ modulator --- p.102 / Chapter A.4 --- Schematic of the folded-cascode amplifier --- p.103 / Chapter A.5 --- Schematic of biasing circuit --- p.104 / Chapter A.6 --- Schematic of preamplifier in comparator --- p.105 / Chapter A.7 --- Schematic of latched part in comparator --- p.106 / Chapter A.8 --- Schematic of the clock generator --- p.107

This thesis reports original work on digital compensation for frequency dependent transfer characteristics and errors in digital PAM/CPFSK (Pulse Amplitude Modulation/Continuous Phase Frequency Shift Keying) quadrature modulators.A particularly flexible and cost effective approach to the implementation of the base-band section of a radio transmitter is to synthesise base-band signals digitally using a DSP (Digital Signal Processor). This approach is limited, however, by the transfer characteristics and errors in the implementation of practical analogue sub-systems. These practical limitations result in undesirable in-band frequency-dependent shaping of the transmitted signals. In the case of FM (Frequency Modulation) signals, this leads to the generation of unwanted side-lobes in the transmitted RF signal spectrum that interfere with signals in adjacent frequency channels. This results in the transmitted signal failing to meet transmission standards requirements.The digital compensation techniques developed and presented in this thesis allow the reduction of undesirable in-band frequency-dependent signal shaping. It is shown that this enables strict requirements on the spectral emissions from the FM transmitter to be met using a flexible and cost effective DSP based modulator system.The contributions of the thesis are in three primary areas:(i) The development of a structure for frequency dependent digital compensation.(ii) The formulation and solution of an optimisation problem that allows the free parameters within the structure to be determined such that effective reduction of unwanted in-band frequency-dependent signal shaping is achieved.(iii) The development of techniques that allow the digital compensation procedure to be successfully implemented on a practical DSP platform.The new digital compensation structure that is proposed uses two digital FIR (Finite ++ / Impulse Response) filters in the digital base-band section of the quadrature modulator: one in the in-phase (I) channel and one in the quadrature (Q) channel. The tap-weights of the FIR filters are determined by solving two optimisation problems: one for each channel. The optimisation problems are formulated using a new approach that ensures that the degrees of freedom in the optimisation i.e., the FIR filter tap-weights, are used effectively to meet the objective of reducing in-band frequency-dependent signal shaping in analogue sub-systems further down the transmission path.A characterisation of the solutions to the optimisation problems enables the identification of techniques that need to be adopted to successfully implement the proposed digital compensation on a practical DSP-based system.The digital compensation technique is demonstrated by implementing and testing the technique on a DSP platform. The results of experimental studies are presented which clearly demonstrate that the digital compensation technique leads to substantial reductions in adjacent channel interference.

Switched-capacitor (SC) circuits are commonly used for analog signal processing because they can be used to realize precision filters and data converters on an integrated circuit (IC). However, for high speed applications SC circuit operating speeds are limited by the internally-compensated opamps found in SC integrators, a common building block of these circuits. This thesis studies gain stages that eliminate the internal compensation, thus allowing the SC circuits to operate at significantly higher operating speeds. An inverter-based SC integrator is presented. The proposed SC integrator is built with a pseudo-differential structure to improve its rejection of common-mode noise, such as charge injection and clock feedthrough. The proposed integrator also incorporates correlated double sampling (CDS) to boost its effective DC gain. Clock-boosting and switch bootstrapping techniques are not used in the proposed circuit, even though it uses a low supply voltage. To verify the speed advantage of the proposed circuit, a high speed delta sigma (Δ∑) modulator was designed in a 1.8V, 0.18μm CMOS technology. The designed Δ∑ modulator operates at a clock frequency of 500MHz. Circuit implementation and layout floorplan are described. The design is based on MATLAB and SpectreS simulations. / Graduation date: 2002

The transition from second-generation (2G) to third-generation (3G) wireless cellular and cordless telephone systems requires multi-standard adaptability in a single RF receiver equipment. An important answer to this request is the use of Delta-Sigma modulators for IF-to-baseband conversion, which will satisfy the dynamic range requirements for digital signal processing, and at the same time, add adaptability and programmability to the characteristics of a RF receiver. This thesis addresses the issues of designing a Delta-Sigma modulator for a multi-standard wireless receiver. A single-loop third-order modulator topology suitable for low power and high integration multi-standard receiver design is proposed. The trade-offs in the modulator design are also presented and explained. The modulator, which has been implemented as a part of a monolithic receiver chip, will be fabricated in a standard 0.35-��m CMOS process. The post-layout simulation results have verified the outcomes of system analysis. / Graduation date: 2004

Delta-sigma modulators are currently a very popular technique for making high-resolution analog-to-digital and digital-to-analog converters (ADCs and DACs). Most delta-sigma modulators in production today employ single-bit quantization because a 1-bit DAC is inherently linear, whereas a multi-bit DAC is not. Were it not for this drawback, the use of multi-bit quantization would improve a delta-sigma modulator's performance by increasing the modulator's resolution or increasing the modulators's bandwidth, while at the same time whitening the quantization noise and improving modulator stability. This thesis explores the element-mismatch-shaping technique, which attenuates the noise caused by static element mismatch in a multi-level DAC by a method similar to delta-sigma modulation. Existing element-matching techniques are reviewed and some analytical and architectural work related to the realization of mismatch-shaping logic is presented. A custom switched-capacitor (SC) DAC is used to verify various element mismatch-shaping algorithms. Experiments show that mismatch-shaping can reduce harmonic distortion by up to 30 dB. / Graduation date: 1998