The Expanded Very Large Array

In almost 30 years of operation, the Very Large Array (VLA) has proved to be a remarkably flexible and productive radio telescope. However, the basic capabilities of the VLA have changed little since it was designed. A major expansion utilizing modern technology is currently underway to improve the capabilities of the VLA by at least an order of magnitude in both sensitivity and in frequency coverage. The primary elements of the Expanded Very Large Array (EVLA) project include new or upgraded receivers for continuous frequency coverage from 1 to 50 GHz, new local oscillator, intermediate frequency, and wide bandwidth data transmission systems to carry signals with 16 GHz total bandwidth from each antenna, and a new digital correlator with the capability to process this bandwidth with an unprecedented number of frequency channels for an imaging array. Also included are a new monitor and control system and new software that will provide telescope ease of use. Scheduled for completion in 2012, the EVLA will provide the world research community with a flexible, powerful, general-purpose telescope to address current and future astronomical issues.Comment: Added journal reference: published in Proceedings of the IEEE, Special Issue on Advances in Radio Astronomy, August 2009, vol. 97, No. 8, 1448-1462 Six figures, one tabl

Radar Technology

In this book “Radar Technology”, the chapters are divided into four main topic areas: Topic area 1: “Radar Systems” consists of chapters which treat whole radar systems, environment and target functional chain. Topic area 2: “Radar Applications” shows various applications of radar systems, including meteorological radars, ground penetrating radars and glaciology. Topic area 3: “Radar Functional Chain and Signal Processing” describes several aspects of the radar signal processing. From parameter extraction, target detection over tracking and classification technologies. Topic area 4: “Radar Subsystems and Components” consists of design technology of radar subsystem components like antenna design or waveform design

a PC based SDR platform with dynamic reconfiguration

The goal of this Major Qualifying Project is to provide the framework for integration of a Virtex series field programmable gate array (FPGA) into GNU Radio, allowing GNU Radio to have control over both FPGA and non-FPGA components of the pipeline. In this report, we address the following: our research into the which FPGA series would be most beneficial to our project, an outline of the evolution of our design over the course of the past 21 weeks, and a summary of the final outcomes in various subsets of project development

RHINO software-defined radio processing blocks

This MSc project focuses on the design and implementation of a library of parameterizable, modular and reusable Digital IP blocks designed around use in Software-Defined Radio (SDR) applications and compatibility with the RHINO platform. The RHINO platform has commonalities with the better known ROACH platform, but it is a significantly cut-down and lowercost alternative which has similarities in the interfacing and FPGA/Processor interconnects of ROACH. The purpose of the library and design framework presented in this work aims to alleviate some of the commercial, high cost and static structure concerns about IP cores provided by FPGA manufactures and third-party IP vendors. It will also work around the lack of parameters and bus compatibility issues often encountered when using the freely available open resources. The RHINO hardware platform will be used for running practical applications and testing of the blocks. The HDL library that is being constructed is targeted towards both novice and experienced low-level HDL developers who can download and use it for free, and it will provide them experience of using IP Cores that support open bus interfaces in order to exploit SoC design without commercial, parameter and bus compatibility limitations. The provided modules will be of particularly benefit to the novice developers in providing ready-made examples of processing blocks, as well as parameterization settings for the interfacing blocks and associated RF receiver side configuration settings; all together these examples will help new developers establish effective ways to build their own SDR prototypes using RHINO

Accurate magnetic sensor system integrated design

Inductive measurement of magnetic fields is a diagnostic technique widely used in several scientific fields, such as magnetically confined fusion, plasma thrusters and particle accelerators, where real time control and detailed characterization of physics phenomena are required. The accuracy of the measured data strongly influences the machine controllability and the scientific results. In the framework of the assembly modifications of the RFX-mod experiment, a complete renew and improvement of the magnetic diagnostic system, from the probes moved inside the vacuum vessel to the integrator modules, has been carried out. In this paper, the whole system making up the magnetic diagnostics is described, following the acquisition chain from the probe to the streamed data and illustrating the requirements and conflicting limitations which affect the different components, in order to provide a comprehensive overview useful for an integrated design of any new systems. The characterization of a prototypical implementation of the whole acquisition chain is presented, focusing on the flexible ADC architecture adopted for providing a purely numerical signal integration, highlighting the advantages that this technology offers in terms of flexibility, compactness and cost effectiveness, along with the limitations found in existing implementation in terms of ADC noise characteristics and their possible solutions

Compensação da não-linearidade do modulador-MZ-IQ baseada em FPGA

Mestrado em Engenharia Electrónica e TelecomunicaçõesNos últimos anos, a crescente necessidade de largura de banda e a evolução das técnicas de processamento digital de sinal renovaram o interesse pelos sistemas de comunicação ópticos coerentes. O modulador IQ assume-se como um componente chave nestes transmissores, sendo responsável pela conversão de informação do domínio eléctrico para o domínio óptico. Os moduladores Mach-Zehnder que constituem este dispositivo recebem sinais de drive com uma excursão controlada, garantindo a utilização de uma região aproximadamente linear das suas funções transferência e a geração de constelações sem distorções de fase. No entanto, existem vantagens em explorar a extensão completa da característica dos moduladores. Neste contexto, torna-se relevante efectuar um estudo acerca das técnicas de pré-distorção electrónica que permitem corrigir os efeitos das não-linearidades associadas a este método de transmissão. Esta dissertação foca-se no estudo da compensação dos impactos que a característica não-linear do modulador Mach-Zehnder tem nos sistemas de transmissão ópticos coerentes. Após a identificação e desenvolvimento de soluções matemáticas para o problema, realizaram-se vários testes utilizando um simulador integrado em ambiente MATLAB. Um sistema de transmissão coerente utilizando formatos de modulação QAM e os respectivos algoritmos de compensação foram posteriormente implementados em FPGA. Desenvolveram-se também co-simulações que permitiram garantir que o hardware concebido produzia os resultados desejados. Para além disso, realizaram-se vários testes utilizando um modulador IQ disponível no “Laboratório de Óptica” do Instituto de Telecomunicações de Aveiro. O objectivo consistiu em operar o sistema em condições laboratoriais e analisar o desempenho dos algoritmos de compensação em ambiente real.In recent years, the ever-increasing bandwidth demand and the evolution of digital signal processing techniques renewed the interest for the optical coherent systems. The IQ-Modulator is a key component in optical coherent transmitters, being responsible for the conversion of information from electrical to optical domain. The Mach-Zehnder modulators that compose this device receive driving signals with a controlled excursion, in order to use an approximately linear region of their transfer function and produce constellations without phase distortions. However, there are advantages in exploit the full range of the modulators’ characteristic. In this context, a study about the electronic predistortion techniques required to overcome the nonlinear effects associated to this transmission method becomes relevant. The subject of this dissertation is the compensation of impairments related to the nonlinear characteristic of the Mach-Zehnder Modulator in coherent optical transmission systems. After the identification and development of mathematical solutions for the problem, several tests were made using a simulator that runs in a MATLAB environment. A QAM coherent transmitter system and the compensation algorithm were then implemented in a FPGA platform. Co-simulations were performed in order to prove that the designed hardware was generating correct results. Furthermore, some tests were conducted using an IQ-Modulator available in the “Optics Laboratory” at Telecommunications Institute of Aveiro. The goal was to operate the system under laboratorial conditions and analyze the performance of the compensation algorithm in a real case scenario

A reconfigurable acoustic telemetry transmitter employing crystal-less temperature-independent frequency reference for oil drilling applications

Ph.DDOCTOR OF PHILOSOPH