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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Design of a Voltage Controlled Oscillator for Galileo/GPS Receiver

Murugan, Deepak January 2012 (has links)
The main aim of this thesis is to implement a voltage-controlled oscillator for a Galileo/GPS receiver with a center frequency of 1.5 GHz in 150 nm CMOS process. As the designed VCO has to be integrated in a phase locked loop, VCO gain is selected high enough for the PLL to lock even with process variations. A new state of art architecture called double harmonic tuned VCO is selected and designed for this GPS application. It uses a complex combination of inductors and capacitors to reduce phase-noise of the VCO by suppressing second harmonic oscillations in the tail node of VCO. The designed VCO shows significant improvement in phase-noise performance compared to a normal LC tank VCO by reducing phase-noise around 4 dBc/Hz. The VCO has a phase-noise of -128 dBc/Hz at 1 MHz offset from center frequency with a power consumption of 5 mW and a tuning range of about 257 MHz for a 1 V tuning voltage range.
12

Design and Development of Gigahertz Range VCO Based on Intrinsically Tunable Film Bulk Acoustic Resonator

Tayari, Danial January 2012 (has links)
The purpose of this thesis is to design and fabricate Gigahertz range voltage controlled oscillator based on intrinsically tunable film bulk acoustic resonator.Modified Butterworth Van Dyke (MBVD) model was studied and implemented to simulate FBAR behavior. Advanced designed system (ADS) was used as the simulation tool.Oscillator theory is studied and an oscillator based on non-tunable FBAR at 2GHz is simulated which shows -132 dBc/Hz phase noise @ 100 kHz offset frequency.A 5.5 GHz Voltage controlled oscillator based on intrinsically tunable FBAR is designed. Frequency tuning of 129 MHz with phase noise of -106 dBc/Hz @ 100 kHz is achieved. The circuit is designed on a novel carrier substrate which includes integrated resonators and passive components. Bipolar junction transistors are mounted on the carrier substrate by silver epoxy. The thesis describes the design, development and processing of the carrier substrate, BSTO based resonators, and the oscillator circuit.
13

A Low Jitter High Linearity Voltage Controlled Oscillator

Tzuhsuan, Peng 15 July 2004 (has links)
Phase locked loops (PLL) are used in many applications. Application examples include clock and data recovery, clock synthesis, frequency synthesis, modulator, and de-modulator. In many circuits, PLL must provide an output clock to follow the input clock closely. For high speed environments, the noises also rise up. Noises mainly come from the power supply and substrate. They produce jitter. A low jitter design is important in PLL circuit. In this thesis, we discuss the Voltage Controlled Oscillator (VCO) which has the largest jitter in PLL system. We propose a low jitter voltage controlled oscillator designed in TSMC 0.35£gm 2P4M Mixed-Signal process technology. We include a regulator to reduce jitter by increasing the VCO PSRR. This structure also provides a high linearity gain (Kvco) which decreases the VCO jitter in the PLL circuit and improve the system stability.
14

Low power VCO-based analog-to-digital conversion

Gupta, Amit Kumar 08 September 2015 (has links)
This dissertation presents novel two stage ADC architecture with a VCO based second stage. With the scaling of the supply voltages in modern CMOS process it is difficult to design high gain operational amplifiers needed for traditional voltage domain two-stage analog to digital converters. However time resolution continues to improve with the advancement in CMOS technology making VCO-based ADC more attractive. The nonlinearity in voltage-to-frequency transfer function is the biggest challenge in design of VCO based ADC. The hybrid approach used in this work uses a voltage domain first stage to determine the most significant bits and uses a VCO based second stage to quantize the small residue obtained from first stage. The architecture relaxes the gain requirement on the the first stage opamp and also relaxes the linearity requirements on the second stage VCO. The prototype ADC built in 65nm CMOS process achieves 63.7dB SNDR in 10MHz bandwidth while only consuming 1.1mW of power. The performance of the prototype chip is comparable to the state-of-art in terms of figure-of-merit but this new architecture uses significantly less circuit area. / text
15

A CMOS QPSK Demodulator Frontend for GPON

Chen, Fei 30 June 2010 (has links)
This thesis examines the design of a QPSK demodulator frontend for GPON transceiver at end user's side. Since lowering the cost of the terminal transceivers in an access network like GPON is a key requirement, CMOS technology is used and several area-saving design techniques are applied. The designed frontend circuit saved more than 80% area of the key components like the mixers and the QVCO than some published designs which can also fit the application. A measurement in frequency domain and a simulation in time domain verified that this frontend is able to demodulate a QPSK signal with a data rate as high as 5 Gbit/s. Two structures of quadrature oscillators are firstly presented and compared. One is an LC QVCO centered at 5 GHz, which has a tuning range of 3 GHz, a phase noise of -100.8 dBc/Hz at 1 MHz offset, and an area of 0.15 mm2 excluding pads. The other is a ring QVCO which only takes an area of 0.019 mm2. But it has a higher phase noise of -81 dBc/Hz at 1 MHz offset. Then two broadband mixers are described separately. The first one provides a high conversion gain, but its input linearity is insufficient to meet the input power requirement. The second mixer obtains required input linearity but with a trade-off of conversion gain. Both mixers have a broadband input impedance match from 2 GHz to 8 GHz. The first mixer has a conversion gain of 8.5 dB and an input 1 dB compresion point at -17 dBm. The second mixer has a conversion gain of -7 dB with an on-chip buffer or -2.1 dB without buffer, but an input 1 dB compresion point at -5 dBm. A frontend circuit is lastly presented. It integrates the compact ring QVCO, two broadband mixers with high input linearity, and two second-order LC ladder low pass filters. A Frequency domain measurement shows the expected spectrum down conversion of a 2.5 Gsym/s QPSK signal centered at 5 GHz. The whole frontend circuit including pads takes 1 mm2 area, and consumed 157 mW power. / Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2010-06-29 10:59:45.312
16

InP DHBT-based clock and data recovery circuits for ultra-high-speed optical data links

Makon, Robert Elvis January 2006 (has links)
Zugl.: Karlsruhe, Univ., Diss., 2006
17

FM vysílač APRS telemetrických dat v pásmu 144MHz / FM Transmitter of APRS Telemetry in 144MHz Band

Sabol, Martin January 2010 (has links)
This work deals with analysis of protocol APRS Automatic Positioning System for telemetry. There is analyzed the structure of the most important frames and their application. It discusses the processing of GPS data and subsequent modulation of the selected frequency. This work also describes and discusses the proposed peripheral devices and the used firmware.
18

High Frequency VCO and Frequency Divider in VLSI 90nm Technology

Veerakitti, Paesol 08 July 2010 (has links)
No description available.
19

A VHF/UHF Voltage Controlled Oscillator in 0.5um BiCMOS

Bosley, Ryan Travis 08 April 2003 (has links)
The dramatic increase in market demand for wireless products has inspired a trend for new designs. These designs are smaller, less expensive, and consume less power. A natural result of this trend has been the push for components that are more highly integrated and take up less real estate on the printed circuit board (PCB). Major efforts are underway to reduce the number of integrated circuits (ICs) in newer designs by incorporating several functions into a single chip. Availability of newer technologies such as silicon bipolar with complementary metal oxide semiconductor (BiCMOS) has helped facilitate this move toward more complex circuit topologies onto one die. BiCMOS achieves efficient chip area utilization by combining bipolar transistors, suited for higher frequency analog circuits with CMOS transistors that are useful for digital functions and lower frequency analog circuits. A voltage controlled oscillator (VCO) is just one radio frequency (RF) circuit block that can benefit from a more complex semiconductor process like BiCMOS. This thesis presents the design and evaluation of an integrated VCO in the IBM 5S BiCMOS process. IBM 5S is a 0.5 um, single poly, five-metal process with surface channel PFETs and NFETs. The process also features self-aligned extrinsic base NPN bipolar devices exhibiting ft of up to 24 GHz. The objective of this work is to obtain a VCO design that provides a high degree of functionality while maximizing performance over environmental conditions. It is shown that an external feedback and resonator network as well as a bandgap voltage referenced bias circuit help to achieve these goals. An additional objective for this work is to highlight several pragmatic issues associated with designing an integrated VCO capable of high volume production. The Clapp variant of the Colpitts topology is selected for this application for reasons of robust operation, frequency stability, and ease of implementing in integrated form. Design is performed at 560 MHz using the negative resistance concept. Simulation results from Pspice and the Agilent ADS are presented. Implementation related issues such as bondwire inductances and layout details are covered. The VCO characterization is shown over several environmental conditions. The final nominal design is capable of: tuning over 150 MHz (22%) and delivering â 4.2 dBm into a 50 Ohm load while consuming only 9mA from a 3.0V supply. The phase noise at these conditions is -92.5 dBc/Hz at a frequency offset of 10 kHz from the carrier. Finally, the conclusion of this work lists some suggestions for potential future research. / Master of Science
20

Représentation et traitement des signaux analogiques dans le domaine temporel, pour répondre aux défis des technologies CMOS très avancées / Time domain analog signal processing in advanced nodes

Buffeteau, David 24 October 2018 (has links)
Dans un contexte de réduction des tailles de transistors dans les technologies CMOS très avancées entraînant la réduction des tensions d’alimentation et par conséquent des dynamiques disponibles pour la représentation des signaux analogiques, ce travail de thèse vise à proposer une alternative à la représentation des données dans le domaine de l’amplitude. La solution qui a été retenue est une représentation de la donnée dans le domaine temporel.Dans ce manuscrit nous étudions à la fois la conversion d’une donnée analogique dans le domaine temporel via, notamment, un convertisseur analogique numérique basé sur un oscillateur contrôlé en tension mais aussi les possibilités de calculs sur des signaux supports d’une information déjàcodée dans le domaine temporel.Nous proposons à l’issu de ce travail à la fois une méthode pour numériser une information temporel afin de pouvoir effectuer des calculs complexes avec, une méthode « d’extraction du résidu » pour améliorer les performances d’un VCO-based ADC en termes de résolution par rapport à la bande passante et une architecture de « convertisseur hybride » permettant d’adapter sonfonctionnement entre un mode dégradé asynchrone et peu consommant et un mode performant synchrone et plus gourmand en énergie tout en mettant en avant le potentiel de ces solutions au travers de simulations dont les modèles se basent sur la technologie CMOS FDSOI en 28 nm. / Advanced CMOS nodes trend to reduce the size of transistors hence reducing the power supply voltages and consequently available dynamics for the representation of analog signals. This work aims at proposing a data representation alternative which is usually done by an amplitude value. The chosen solution is to use a time-domain representation.In this thesis, we study both the use of a VCO-based ADC to convert an analog data into a time-domain one and a calculating method using data already encoded into the time domain.The three pillars of this thesis are a method to digitize a time-domain data so as to do more complex calculations, a method with a « residue extraction » allowing us to improve VCO-based ADCs performance in terms of resolution for a given bandwidth and an innovative architecture of a hybrid ADC which can adjust its operation switching between an asynchronous low-performance mode (which is a low power mode) and a synchronous high-performance mode (which is more energy consuming). The potential of these methods is pointed out by means of simulations that mimic the behavior of the 28 nm FDSOI CMOS technology.

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