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Frequency syntheses with delta-sigma modulations and their applications for mixed signal testingYang, Dayu, Dai, Foster. January 2006 (has links)
Dissertation (Ph.D.)--Auburn University,2006. / Abstract. Vita. Includes bibliographic references (p.110-113).
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Double-sampled digital-feedforward second-order delta-sigma modulatorSukhon, Mohammad T. N., January 1900 (has links)
Thesis (M.Eng.). / Written for the Dept. of Electrical and Computer Engineering. Title from title page of PDF (viewed 2009/06/17). Includes bibliographical references.
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Energy efficient digital baseband modulator for cable terminal systems targeted on field programmable gate array /Wang, Feng. January 2004 (has links)
Thesis (M.S.)--Ohio University, June, 2004. / Includes bibliographical references (p. 99-100).
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Energy efficient digital baseband modulator for cable terminal systems targeted on field programmable gate arrayWang, Feng. January 2004 (has links)
Thesis (M.S.)--Ohio University, June, 2004. / Title from PDF t.p. Includes bibliographical references (p. 99-100)
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Improved design techniques for analog and mixed circuits /Nishida, Yoshio. January 1900 (has links)
Thesis (Ph. D.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 79-82). Also available on the World Wide Web.
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Caracterização das propriedades acústicas de um modulador acusto-óptico de fibra de cristal fotônicoSilva, Ricardo Ezequiel da 05 August 2011 (has links)
CAPES / Este trabalho descreve a caracterização de ondas acústicas flexurais que se propagam em fibras de cristal fotônico, nas quais estão gravadas Redes de Bragg, e que são excitadas com auxílio de um modulador acusto-óptico. Para sua medida foi desenvolvido um sistema óptico interferométrico, que permitiu a detecção das deflexões mecânicas do transdutor piezoelétrico e da fibra. Medidas da frequência e do período permitiram estimar a velocidade de fase das ondas acústicas flexurais. As ressonâncias do transdutor são verificadas até uma frequência de excitação de 1 MHz. Resultados de medidas realizadas em fibras monomodo convencionais também são apresentados, e as velocidades de fase estimadas são comparadas entre os dois tipos de fibra. / This work describes the characterization of flexural acoustic waves propagating in Photonic Crystal Fibers with inscribed Bragg gratings, which are excited by means of an acoustic-optic modulator. An interferometric optical system was developed in order to measure the flexural deformations of the piezoelectric transducer and of the fiber. Measurements of the excitation frequency and period allowed the phase velocity estimation of the flexural acoustic waves. The transducer resonances are checked up to an excitation frequency of 1 MHz. Measured values obtained in standard single mode fibers are also presented and the estimated phase velocities between both types of fibers are compared.
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Systems Engineering for Silicon Photonic DevicesZhu, Xiaoliang January 2015 (has links)
The increasing integration of digital information with our daily lives has led to the rise of big data, cloud computing, and the internet of things. The growth in these categories will lead to an exponential increase in the required capacity for data centers and high performance computation. Meanwhile, due to bottlenecks in data access caused by the limited energy and bandwidth scalability of electrical interconnects, computational speedup can no longer scale with demand. A better solution is necessary in order to increase computational performance and reduce the carbon footprint of our digital future.
People have long thought of photonic interconnects, which can offer higher bandwidth, greater energy efficiency, and orders-of-magnitude distance scalability compared to electrical interconnects, as a solution to the data access bottleneck in chip, board, and datacenter scale networks. Over the past three decades we have seen impressive growth of photonic technology from theoretical predictions to high-performance commercially available devices. However, the dream of an all-optical interconnection network for use in CPU, Memory, and rack-to-rack datacenter interconnects is not yet realized. Many challenges and obstacles still have to be addressed. This work investigates these challenges and describe some of the ways to overcome them.
First we will first examine the pattern sensitivity of microring modulators, which are likely to be found as the first element in an optical interconnect. My work will illustrate the advantage of using depletion mode modulators compared to injection mode modulators as the number of consecutive symbols in the data pattern increases.
Next we will look at the problem of thermal initialization for microring demultiplexers near the output of the optical interconnect. My work demonstrates the fastest achieved initialization speed to-date for a microring based demultiplexer. I will also explore an thermal initialization and control method for microrings based on temperature measurement using a pn-junction.
Finally, we will look at how to control and initialize microring and MZI based optical switch fabrics, which is the second element found in a optical interconnect. Work here will show the possibility of switching high-speed WDM datastreams through microring based switches, as well as methods to deal with the complexities inherent in control and initialization of high-radix switch topologies.
Through these demonstrations I hope to show that the challenges facing optical interconnects, although very real, are surmountable using reasonable engineering efforts.
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An IF-input quadrature continuous-time multi-bit [delta][sigma] modulator with high image and non-linearity suppression for dual-standard wireless receiver application.January 2008 (has links)
Ko, Chi Tung. / On t.p. "delta" and "sigma" appear as the Greek letters. / Thesis submitted in: December 2007. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references. / Abstracts in English and Chinese. / Abstract --- p.1 / 摘要 --- p.3 / Acknowledgements --- p.4 / Table of Contents --- p.5 / List of Figures --- p.8 / List of Tables --- p.13 / Chapter Chapter 1 --- Introduction --- p.14 / Chapter 1.1 --- Motivation --- p.14 / Chapter 1.2 --- Objectives --- p.17 / Chapter 1.3 --- Organization of the Thesis --- p.17 / References --- p.18 / Chapter Chapter 2 --- Fundamentals of Delta-sigma Modulators --- p.20 / Chapter 2.1 --- Delta-sigma Modulator as a Feedback System --- p.20 / Chapter 2.2 --- Quantization Noise --- p.22 / Chapter 2.3 --- Oversampling --- p.23 / Chapter 2.4 --- Noise Shaping --- p.25 / Chapter 2.5 --- Performance Parameters --- p.27 / Chapter 2.6 --- Baseband Modulators vs Bandpass Modulators --- p.27 / Chapter 2.7 --- Discrete-time Modulators vs Continuous-time Modulators --- p.28 / Chapter 2.8 --- Single-bit Modulators vs Multi-bit Modulators --- p.29 / Chapter 2.9 --- Non-linearity and Image Problems in Multi-bit Delta-sigma Modulators --- p.29 / Chapter 2.9.1 --- Non-linearity Problem --- p.29 / Chapter 2.9.2 --- Image Problem --- p.31 / Reference --- p.36 / Chapter Chapter 3 --- Image Rejection and Non-linearity Suppression Techniques for Quadrature Multi-bit Δ¡♭ Modulators --- p.38 / Chapter 3.1 --- Quadrature DEM Technique --- p.38 / Chapter 3.1.1 --- Introduction and Working Principle --- p.38 / Chapter 3.1.2 --- Behavioral Simulation Results --- p.42 / Chapter 3.2 --- IQ DWA Technique --- p.44 / Chapter 3.2.1 --- Introduction and Working Principle --- p.44 / Chapter 3.2.2 --- Behavioral Simulation Results --- p.49 / Chapter 3.3 --- DWA and Bit-wise Data-Dependent DEM --- p.52 / Chapter 3.3.1 --- Introduction and Working Principle --- p.52 / Chapter 3.3.2 --- Behavioral Simulation Results --- p.54 / Chapter 3.4 --- Image Rejection Technique for Quadrature Mixer --- p.61 / Chapter 3.5 --- Conclusion --- p.63 / Reference --- p.64 / Chapter Chapter 4 --- System Design of a Multi-Bit CT Modulator for GSM/WCDMA Application --- p.65 / Chapter 4.1 --- Objective of Design and Design Specification --- p.65 / Chapter 4.2 --- Topology Selection --- p.65 / Chapter 4.3 --- Discrete-time Noise Transfer Function Generation --- p.66 / Chapter 4.4 --- Continuous-time Loop Filter Transfer Function Generation --- p.69 / Chapter 4.5 --- Behavioral Model of Modulator --- p.69 / Chapter 4.6 --- Dynamic Range Scaling --- p.75 / Chapter 4.7 --- Behavioral Modeling of Operational Amplifiers --- p.77 / Chapter 4.8 --- Impact of RC Variation on Performance --- p.85 / Chapter 4.9 --- Loop Filter Component Values --- p.88 / Chapter 4.10 --- Summary --- p.90 / Reference --- p.90 / Chapter Chapter 5 --- Transistor-level Implementation of Modulators --- p.92 / Chapter 5.1 --- Overview of Design --- p.92 / Chapter 5.2 --- Design of Operational Transconductance Amplifiers (OTAs) --- p.94 / Chapter 5.2.1 --- First Stage --- p.94 / Chapter 5.2.2 --- Second and Third Stages --- p.98 / Chapter 5.3 --- Design of Feed-forward Transconductance (Gm) Cells --- p.101 / Chapter 5.4 --- Design of Quantizer --- p.102 / Chapter 5.4.1 --- Reference Ladder Design --- p.102 / Chapter 5.4.2 --- Comparator Design --- p.104 / Chapter 5.5 --- Design of Feedback Digital-to-Analog Converter (DAC) --- p.106 / Chapter 5.5.1 --- DWA and DEM Logic --- p.107 / Chapter 5.5.2 --- DAC Circuit --- p.109 / Chapter 5.6 --- Design of Integrated Mixers --- p.111 / Chapter 5.7 --- Design of Clock Generators --- p.112 / Chapter 5.7.1 --- Master Clock Generator --- p.112 / Chapter 5.7.2 --- LO Clock Generator --- p.114 / Chapter 5.7.3 --- Simulation Results --- p.116 / Reference --- p.125 / Chapter Chapter 6 --- Physical Design of Modulators --- p.127 / Chapter 6.1 --- Floor Planning of Modulator --- p.127 / Chapter 6.2 --- Shielding of Sensitive Signals --- p.130 / Chapter 6.3 --- Common Centroid Layout --- p.130 / Chapter 6.4 --- Amplifier Layout --- p.132 / Reference --- p.137 / Chapter Chapter 7 --- Conclusions --- p.138 / Chapter 7.1 --- Conclusions --- p.138 / Chapter 7.2 --- Future Works --- p.138 / Appendix A Schematics of Building Blocks --- p.140 / First Stage Operational Amplifier --- p.140 / First Stage Amplifier Local Bias Circuit --- p.140 / Second and Third Stage Operational Amplifier --- p.141 / Second and Third Stage Local Bias Circuit --- p.141 / CMFB Circuit (First Stage) --- p.142 / CMFB Circuit (Second Stage) --- p.142 / Gm-Feed-forward Cells --- p.143 / Gm Feed-forward Cell Bias Circuit --- p.143 / Reference Ladder Circuit --- p.144 / Pre-amplifier Circuit --- p.145 / Latch Circuit --- p.145 / DAC Circuit (Unit Cell) --- p.146 / Author's Publications --- p.147
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Low voltage switched capacitor circuits for lowpass and bandpass [delta sigma] convertersKeskin, Mustafa 07 December 2001 (has links)
The most accurate method for performing analog signal processing in MOS
(metal-oxide-semiconductor) integrated circuits is through the use of switched-capacitor
circuits. A switched-capacitor circuit operates as a discrete-time signal
processor. These circuits have been used in a variety of applications, such as
filters, gain stages, voltage-controlled oscillators, and modulators.
A switched-capacitor circuit contains operational amplifiers (opamps), capacitators,
switches, and a clock generator. Capacitors are used to define the state
variables of a system. They store charges for a defined time interval, and determine
the state variables as voltage differences. Switches are used to direct
the flow of charges and to enable the charging and discharging of capacitors.
Nonoverlapping clock signals control the switches and allow charge transfer between
the capacitors. Opamps are used in order to perform high-accuracy charge
transfer from one capacitor to another.
The goal of this research is to design and explore future low-voltage switched-capacitor
circuits, which are crucial for portable devices. Low-voltage operation
is needed for two reasons: making reliable and accurate systems compatible with
the submicron CMOS technology and reducing power consumption of the digital
circuits.
To this end, three different switched-capacitor integrators are proposed, which
function with very low supply voltages. One of these configurations is used to
design a lowpass ����� modulator for digital-audio applications. This modulator
is fabricated and tested demonstrating 80 dB dynamic range with a 1-V supply
voltage.
The second part of this research is to show that these low-voltage circuits are
suitable for modern wireless communication applications, where the clock and
signal frequencies are very high.
This part of the research has focused on bandpass analog-to-digital converters.
Bandpass analog-to-digital converters are among the key components in
wireless communication systems. They are used to digitize the received analog
signal at an intermediate center frequency. Such converters are used for digital
FM or AM radio applications and for portable communication devices, such as
cellular phones. The main block, in these converters, is the resonator, which is
tuned to a particular center frequency. A resonator must be designed such that
it has a sharp peak at a specific center frequency. However, because of circuit
imperfections, the resonant peak gain and/or the center frequency are degraded
in existing architectures.
Two novel switched-capacitor resonators were invented during the second
part of this research. These resonators demonstrate superior performance as
compared to previous architectures. A fourth-order low-voltage bandpass �����
modulator, using one of these resonators, has been designed. / Graduation date: 2002
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Improving a sampled-data circuit simulator for Delta-Sigma modulator designHayward, Roger D. 30 April 1992 (has links)
Delta-Sigma Modulator-based Analog-to-Digital converter design is an active
area of research. New topologies require extensive simulations to verify their
performance. A series of improvements were made to an existing circuit
simulation package in order to speed the simulation process for the designer.
Various examples of these improvements are presented in typical applications. / Graduation date: 1992
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