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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.
41

Biophysical studies of fetal lambs in utero

Schier, Dr Mark Unknown Date (has links) (PDF)
The monitoring of fetal lambs in-vivo, has been previously carried out by using hard-wires. This work presents an alternative method for monitoring, by use of radiofrequency biotelemetry, with which there are no hard wires. With biotelemetry, a more "natural" recording may take place from the fetus. Long term, natural monitoring of fetal development has not been possible in the past.The design and implementation of a system capable of providing continuous, isolated monitoring is presented. The problems associated with the development and subsequent use of this system will be presented, especially the problem of noise.Data acquisition and analysis methods are also introduced and developed to suit the large amounts of information produced by the biotelemetry system.Analysed data from two fetal animals are presented and the significance of the reduced information is discussed.
42

Direct-sequence spread-spectrum modulation for utility packet transmission in underwater acoustic communication networks /

Duke, Peter S. January 2002 (has links) (PDF)
Thesis (M.S. in Electrical Engineering)--Naval Postgraduate School, September 2002. / Thesis advisor(s): Roberto Cristi, Joseph Rice. Includes bibliographical references (p. 129-130). Also available online.
43

Bandwidth optimization of underwater acoustic communications systems

Houdeshell, Jack E. January 2001 (has links) (PDF)
Thesis (M.S. in Engineering Acoustics) Naval Postgraduate School, March 2001. / Thesis advisor(s): Smith, Kevin B. ; Nagle, Daniel T. "March 2001." Includes bibliographical references (p. 39-40). Also Available in print.
44

Event-driven simulation and analysis of an underwater acoustic local area network

Goh, Meng Chong. January 2010 (has links) (PDF)
Thesis (M.S. in Engineering Acoustics)--Naval Postgraduate School, June 2010. / Thesis Advisor(s): Rice, Joseph A. "June 2010." Description based on title screen as viewed on July 13, 2010. Author(s) subject terms: Communications network, sensor network, acoustic communications, undersea sensors, simulation, Seastar, Seaweb Includes bibliographical references (p. 89-90). Also available in print.
45

Equalization techniques for multipath mitigation in aeronautical telemetry /

Paje, Vladimir Ignacio, January 2005 (has links) (PDF)
Thesis (M.S.)--Brigham Young University. Dept. of Electrical and Computer Engineering, 2005. / Includes bibliographical references (leaves 53-54).
46

Use of microcontrollers for diver monitoring by underwater acoustic biotelemetry in multipath environments

Habib Istepanian, Robert S. January 1994 (has links)
Biomedical Telemetry (Biotelemetry) is a special facet of bio-instrumentation which provides a means for transmitting physiological or biological information from one site to another. There are numerous situations in which it is desirable to monitor critical physiological reflexes and responses from freely swimming swimmers or divers. The design and implementation of a novel multi-channel digital acoustic biotelemetry system using a single-chip microcontroller is described. It is intended for monitoring the electrocardiogram (ECG), heart rate, breathing rate and depth of a free swimming diver, but the system has a modular design that can be adapted for the transmission of digital data representing any parameter. The use of the microcontroller enables the digital data to be transmitted in a priority interrupt format from each sensor with programmable pulse width timing. A portable receiver contains an identical microcontroller and is designed to scan three crystal-controlled frequencies to provide a logical output for each detected signal. These signals are captured by a portable data logger and interfaced to a computer for further processing. This automated arrangement greatly reduces the probability of data error by increasing immunity to multipath and reverberation effects.
47

Narrowband powerline communications on the domestic mains in the CENELEC frequencies

Cooper, David January 2000 (has links)
The object of this dissertation is to identify effective techniques for powerline communication using the low voltage (240V) domestic mains electricity supply in the sub 150 kHz frequency range as defined by the European CENELEC standard, concentrating on narrowband techniques suitable for low data rate telemetry applications. In order to conduct a comparison of communications techniques a model of the channel is invaluable. However a survey of the existing literature reveals that the presently available Knowledge of the channel characteristics and impairments of the low voltage mains is limited. In particular there is no widely accepted quantitative model of the mains as a narrowband communications link. The study consisted of four main phases. First, a new piece of equipment, the 'Channel Probe', was developed to perform channel soundings of the mains. The second phase was largely experimental; empirical channel sounding results were collected using the Channel Probe. In the third phase a model was defined to fit the empirical results and a quantitative simulation was constructed based on this model. Lastly, communications techniques were studied using this simulation. This document presents the key impairments introduced by the channel, and proposes a novel narrowband channel model. Quantitative values for these phenomena are identified and justified against the measured results. The simulation that was constructed in accordance with this channel model is entirely novel, and is used to study suitable modulation schemes, receiver structures and algorithms. Original performance results from this simulation are presented, and a novel low complexity narrowband communication scheme is presented which has significant advantages over existing commercially available systems.
48

Performance enhancement of the Surrey 400 keV ion implanter

Aboukhder, Omar M. January 1990 (has links)
Performance enhancement of the Surrey 400 keV ion implanter has been successfully implemented by upgrading the ion optics and installing a computerised telemetry system. Ion optics improvements include redesigning the mass analyser system and designing and installing a double electrostatic quadrupole lens. Telemetry enhancements entailed designing and installing an "intelligent" multiplexer system within the high voltage terminal and connecting this system to computers at earth potential using only two (Down- and Up-link) fibre optic lines. This new system solved the problem of frequent failures caused by current discharges. Other telemetry improvements included: upgrading all data acquisition and conversion head units especially those monitoring the critical parameters; standardising the design of voltage-to-frequency (V/F) head units and installing these as boxed modules; and, increasing the number of telemetry channels (from 15 to 22) to monitor the (original 15 plus the seven newly developed) sub-systems within the high voltage terminal. Upgrading of the machine optics and electronics not only remedied several of the shortcomings of the original machine, but also worked to produce an equipment with better operational characteristics. Currently, the implanter is capable of resolving ion species with masses up to 241 amu, which enables selected isotopes from across the periodic table to be ion implanted. Ray tracing simulations show that the machine now has a much-improved beam transport efficiency with a smaller and more symmetric beam spot at the target. Experiments using 100 keV Ar+ showed that the beam spot is 5mm x 3mm as against 35mm x 20mm in the old system. At the same time, the implanter has a reliable telemetry system which efficiently links together all of its sub-systems within the high voltage terminal. Performance measurements showed that there has been a significant improvement in channel accuracies (from 1% to at least 0.3%) as well as an increase in its measurement speed, being at least five times faster. The best indicator of implanter reliability, however, is that since the commissioning of both optics and electronics improvements in 1988, there has been no reported telemetry breakdown. This not only provides substantial savings in machine maintenance and repairs, but, also increased the productivity of the implanter. These improvements in hardware have made the machine more amenable to and worthy of computer control. To ensure tighter control and to enhance the reliability of the implanter, a distributed computer control system for the automatic control of the whole implanter has also been designed. Within this control configuration, three types of applications software have been developed, tested and subsequently implemented to control the Beam Generation and Analysis sub-systems. These Assembly code programmes provide the operator with real-time information which enable him to conduct fault diagnosis, parameter calibration, and, on a day to day basis, perform the setting up and control of the implanter. In the future, the software can be expanded and integrated into the final algorithm needed to implement the closed-loop computer control of the implanter. Full automation will further enhance the implanter's performance and reliability. In summary, major improvements have been made to the 400 kV high current implanter at the University of Surrey. This has greatly enhanced the purity of the beam at the target and the reliability of the machine. As a result, this project serves to enhance the quality of research in the field of ion implantation technology within the Department. It also contributes to ongoing research in the development of implanter telemetry and control systems.
49

Framework for Customizable Autopilot Solutions / Framework for Customizable Autopilot Solutions

Raška, Michal January 2017 (has links)
The thesis analyses, designs and implements the framework for creation of customizable autopilot solutions for radio controlled airplanes. As a proof of concept of this framework a set of applications, which use this framework, is cre- ated. The result of this thesis is the extensible modular system, capable of airplane's attitude control, telemetry transmission and wireless communication with the ground station. There is great diversity in the components used by the system, which must be hidden by the framework. The differences must be encased in order to deliver required user experience for the programmers using the frame- work and the end users of the resulting applications as well. The tests, which validate the goals of the thesis indicate, that the resulting system is capable of all required tasks and ready to implement additional features which the end users might require in the future. 1
50

Bluetooth Telemetry System for a Wearable Electrocardiogram

Green, Ryan B (Ryan Benjamin) 17 August 2013 (has links)
The rise of wireless networks has led to a new market in medicine: remote patient monitoring. Practitioners now desire to monitor the health conditions of their patients after hospital release. With the large number of cardiac related deaths and this new demand in medicine being the motivation, this study developed a Bluetooth® telemetry system for a wearable Electrocardiogram. This study also developed a compression t-shirt to hold the ECG and telemetry system. This device communicates the ECG signal of a patient to an Android device within the ISM frequency bands (2.4-2.48 GHz) where the data is displayed and stored in real time. This study is a stepping stone toward more portable heart monitoring that can communicate with the doctor in real time from remote locations.

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