Thesis (PhD)--University of South Australia, 1996

Land mobile radio technology (LMR) has existed since the early 1920's. The most visible manifestation of this technology is the handheld VHF/UHF radios also referred to as 'walkie-talkie'. These handheld devices are one of the most ubiquitous forms of radio communication systems. Most of them are designed for transmitting analog voice signals. Due to an increase in the amount of digitized analog signals over the past few years complemented by a need for transmitting pure digital data, there has been a desire to transmit digital data. There are methods which allow the analog radios to transmit digital data without any modifications; however the data rate achievable using these methods is very low. In contrast, the digital variants of these hand-held radios are capable of transmitting digital data at comparatively higher data rates. However they are expensive and require major infrastructure overhauls. In this thesis, a prototype modem was developed which interfaces with an analog radio without any modifications to the radio. Furthermore, the data rates achievable are comparable with those achieved using digital radios. The modem uses Orthogonal Frequency Division Multiplexing (OFDM) technique to generate an audio band signal which is fed to the radio. The OFDM technique used to generate the audio band signal from data bits ensures maximum bandwidth efficiency. The developed modem is capable of communicating over Ethernet connection. It uses a RJ 45 interface to connect to a data source.

El objetivo principal del presente trabajo de título es el diseño, desarrollo e implementación de un prototipo formado por módulos llamado iNodos, que serán la base de un sistema de telemetría. Esto es, obtener los datos a distancia por medio de varios iNodos, para luego enviarlos a un centro donde se almacene la información. Debido a la creciente demanda de este tipo de soluciones, se hace necesaria la creación de un sistema capaz de realizar estas mediciones de manera remota. Es así como la amplia cobertura de las redes GSM, en conjunto con soluciones inalámbricas de última milla han resuelto el problema de acceso. La principal problemática radica en el costoso cableado requerido por los aparatos electrónicos, así como la dificultad para acceder a ciertos terrenos, muchas veces inaccesibles. Además considerando que los puntos de medición se encuentran en un radio menor de 100 mt, se propone una estructura que considera el uso de una red de módulos XBee interconectados mediante el protocolo de comunicaciones Modbus a un módulo Maestro que a su vez se comunica utilizando la red GSM como un nodo centralizado para enviar los datos.. Este permite una completa y documentada forma de transmitir datos, utilizando protocolos confiables. Para administrar la red de telemetría, se creó un programa en C#, el cual permite obtener los datos provenientes de sensores y guardarlos en una Base de Datos para su posterior proceso. Este programa, se comunica entre las distintas redes de telemetría existentes, con sólo un ID, nombre y clave. El prototipo no sólo permite eliminar el cableado en este tipo de redes, sino que además logra obtener datos de manera remota y confiable, sin la necesidad de estar físicamente en el lugar en donde se toman los datos. Además está hecho de tal forma, que es totalmente escalable, ya que se realizó en base a módulos que cumplen una determinada función. Por lo tanto cada uno de ellos se puede cambiar perfectamente sin ningún inconveniente. Se logró crear un prototipo confiable en cuanto a la transferencia de datos, que permite la medición a distancia con sólo ingresar un simple comando. Para trabajo futuro se recomienda mejorar la interfaz de usuario del programa; permitir agregar sub-nodos y sub-redes para agrandar más el alcance y el número de sensores; y permitir crear una base de datos con los datos, para que la medición se realice de manera programada.

Thesis (M.Tech (Electrical Engineering))--Cape Technikon, 1995 / This thesis describes the design and development ofsoftware for a FAXMODEM card for a personal computer. The software was developed to enable the designed FAXMODEM card to transmit and receive facsimiles independent of the host personal computer.

Please read the abstract in the section 00front of this document / Dissertation (M Eng (Electronic Engineering))--University of Pretoria, 2006. / Electrical, Electronic and Computer Engineering / unrestricted

International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / This paper describes the development of a compact mobile telemetry system using commercial-off-the-shelf components. The personal computer-based systems support microwave pulse code modulation and serial spread-spectrum radio modem telemetry. The mobile ground station provides data display and archiving of test activities, air-ground communications between experimenters and the flight test crew, and acts as a flight test Differential Global Positioning System base station. The success of the systems indicates that functional telemetry capabilities can be established for small flight test programs at modest cost.

Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2007. / The use of emerging microprocessors has become increasingly popular in packet radio communication equipment. This is mainly because of the improved performance and hardware simplicity they offer. The new generation field programmable gate arrays (FPGAs) and microcontrollers are now widely used in the development of terminal node controller (TNC) components. The aim of this thesis is to evaluate the use of these new generation FPGAs and microcontrollers in a TNC design, in order to utilise the software flexibility and hardware simplicity. The design process began with the selection of the available simple microcontroller-based modem that was just designed. Prior to its usage in a TNC, the software of the modem was modelled, in order to understand its signal processing functionality.

Este trabalho apresenta o estudo do sistema ';pi';/4-DQPSK recentemente escolhido como o esquema de modulacao digital para a segunda geracao do distema de comunicacao movel celular. As propriedades que motivaram sua escolha, a definicao dos sistemas de transmissao e recepcao e as caracteristicas de desempenho em canal tipico de comunicacao movel sao aqui estudadas. E feita uma analise dos fenomenos que ocorrem no canal de radio movel e dos modelos capazes de simular tais fenomenos. Apresenta-se o desenvolvimento de um conjunto de programas de computacao que apontam a simulacao do sistema em questao. Baseados nos resultados de diversas simulacoes verifica-se a validade do modelo de dois percursos para o canal seletivo em frequencia. Verificamos tambem como os diferentes perfis de potencia de multipercurso podem afetar o desempenho global do sistema.

Copies of author's previously published articles inserted. / Bibliography: leaves 118-126. / 160 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / The subject of this thesis is the improvement of the design of High fidelity (HF) Radio modems by interpreting the high fidelity radio channel from a signal design perspective. / Thesis (Ph.D.)--University of Adelaide, Dept. of Electrical and Electronic Engineering, 1996?

Η παρούσα ειδική ερευνητική εργασία εκπονήθηκε στα πλαίσια του Διατμηματικού Προγράμματος Μεταπτυχιακών Σπουδών στην “Ηλεκτρονική και Επεξεργασία της Πληροφορίας” στο τμήμα Φυσικής του Πανεπιστήμιου Πατρών. Ο στόχος της παρούσας εργασίας είναι η δημιουργία ενός αναπτυξιακού συστήματος για την υλοποίηση εφαρμογών που απαιτούν τη χρήση του δικτύου κινητής τηλεφωνίας. Το σύστημα αυτό θα πρέπει να μπορεί να λειτουργήσει αυτόνομα χωρίς υποστήριξη υπολογιστή. Το σύστημα έχει τη δυνατότητα χρήσης του δικτύου κινητής τηλεφωνίας (φωνή και δεδομένα) μέσω της χρήσης GSM Modem. Η αλληλεπίδραση με τον χρήστη γίνεται μέσω έγχρωμης οθόνης αφής με ενσωματωμένο resistive touch controller, που συμβάλει στην αυτόνομη λειτουργία του συστήματος. Το DSK 6713, που ενσωματώνει το TMS320C6713 DSP χρονίζεται στα 225 MHz, χρησιμοποιείται σαν κεντρική μονάδα για τη διασύνδεση αυτών αλλά και για την ανάπτυξη της όποιας εφαρμογής. Στο DSP υπάρχει διασυνδεδεμένος Audio Codec, μνήμη RAM και DMA Controller. To DSK C6713 δίνει τη δυνατότητα μέσω θυρών που έχει διαθέσιμες για την διασύνδεση και άλλων εξωτερικών συσκευών όπως κάμερα και SD card. Μαζί με το σύστημα αναπτύχθηκε και κώδικας για την επικοινωνία των υποσυστημάτων, καθώς και μία εφαρμογή γραφικού ισοσταθμιστή που κάνει χρήση δυνατοτήτων του συστήματος για την επίδειξη ορθής λειτουργίας αυτού. Το πρώτο κεφάλαιο αναφέρεται στην διασύνδεση των υποσυστημάτων και στους περιορισμούς που υπήρχαν από την κάθε πλευρά. Στο δεύτερο κεφάλαιο περιγράφονται τα υποσυστήματα που αποτελούν το αναπτυξιακό. Στο τρίτο κεφάλαιο αναλύεται η εφαρμογή που αναπτύχθηκε στην κεντρική μονάδα, ενώ στο τέταρτο κεφάλαιο το τμήμα της εφαρμογής που αναπτύχθηκε στην οθόνη αφής. Τέλος στο τελευταίο κεφάλαιο παρουσιάζονται τα αποτελέσματα της εφαρμογής που υλοποιήθηκε . / This special research work was performed in the frame of the requirements of the M.Sc. "Electronics & Computers" in the Department of Physics at the University of Patras. The purpose of this study is to create a development system for developing applications that require the use of the mobile network. This system should be able to work independently without computer support. The system has the ability to use the mobile network (voice and data) by using GSM Modem. The user interaction is via color touch screen with an integrated resistive touch controller, which contributes to the autonomous system operation. The DSK C6713, which incorporates the TMS320C6713 DSP, that is clocked at 225 MHz, is used as a central unit for interconnecting these and for the development of any application. The DSP is interconnected with an Audio Codec, a RAM Memory and a DMA Controller. The DSK C6713 enables interconnection with other external devices such as camera and SD card. In addition, a code was developed for the communication of the subsystems. An application of a graphic equalizer was developed too, in order to make use of the system capabilities to demonstrate proper operation of this. The first chapter deals with the interconnection of the subsystems and the restrictions that existed on each side. The second chapter describes the subsystems that constitute the development. In the third chapter is described the application developed in the central unit while the fourth chapter presents the section of the application that was developed on the touch screen. Finally the last chapter presents the results of the application that were implemented.