This book describes a new, extremely low frequency (ELF)/ very low frequency (VLF) miniaturized transmitter concept, based on the mechanical motion of permanent magnets or electrets. The authors explain how utilizing the very high energy density of modern ferromagnetic and ferroelectric materials, such “electromechanical transmitters’’ can provide much higher field generation efficiency than conventional antennas, thus enabling practical ELF/VLF wireless communications links. The text begins with the fundamental challenges of such links and provides an historical overview of the attempts that have been made to address these challenges. It then focuses on the design and implementation of practical electromechanical ELF/VLF transmitters, which is an interdisciplinary subject that spans multiple research areas including electromagnetics, power electronics, control systems, and mechanical design. The authors also describe how such transmitters can be combined with receivers and signal processing algorithms to realize complete ELF/VLF links in challenging environments.

Recent emphasis upon the importance of the physical environment has made science and the public even more cog nizant of the many components of the biosphere. While much attention has been given to ionizing electromagnetic stimuli which causes blatant and unalterable changes in biological systems, relatively little research has been concerned with those electromagnetic signals whose frequencies overlap with time-varying processes in living organisms. Extremely low frequency (ELF) electromagnetic fields can occur as waves between about I Hz to 100 Hz or as short pulses within this range of very low frequency (VLF) and higher frequency sources. The natural occurrence of ELF signals is associated with weather changes, solar disturbances and geophysical ionospheric perturbations. Man-made sources have also been reported. Certain physical properties of ELF signals make them excellent candidates for biologically important stimuli. Unlike many other weather components, ELF signals have the capacity to penetrate structures which house living organ isms. ELF wave configurations allow long distance propaga tional capacities without appreciable attenuation of inten sity, thus making them antecedent stimuli to approaching weather changes. Most importantly, ELF signals exhibit the frequencies and wave forms of bio-electrical events that occur within the brain and body. Thus resonance inter actions between animal and nature become attractive possi bilities.

Includes author and subject indexes.

Thorough coverage of basic digital communication system principles ensures that readers are exposed to all basic relevant topics in digital communication system design. The use of CD player and JPEG image coding standard as examples of systems that employ modern communication principles allows readers to relate the theory to practical systems. Over 180 worked-out examples throughout the book aids readers in understanding basic concepts. Over 480 problems involving applications to practical systems such as satellite communications systems, ionospheric channels, and mobile radio channels gives readers ample opportunity to practice the concepts they have just learned. With an emphasis on digital communications, Communication Systems Engineering, Second Edition introduces the basic principles underlying the analysis and design of communication systems. In addition, this book gives a solid introduction to analog communications and a review of important mathematical foundation topics. New material has been added on wireless communication systems—GSM and CDMA/IS-94; turbo codes and iterative decoding; multicarrier (OFDM) systems; multiple antenna systems. Includes thorough coverage of basic digital communication system principles—including source coding, channel coding, baseband and carrier modulation, channel distortion, channel equalization, synchronization, and wireless communications. Includes basic coverage of analog modulation such as amplitude modulation, phase modulation, and frequency modulation as well as demodulation methods. For use as a reference for electrical engineers for all basic relevant topics in digital communication system design.

In 1873 Scottish physicist James Clerk Maxwell first advanced the idea that there might be electromagnetic waves that were similar to light waves, a startling concept to the scientists of his day. About 13 years later, German physicist Heinrich Hertz demonstrated in his laboratory that electromagnetic radiation did indeed exist. But it was not until after Hertz's death that a young Italian named Guglielmo Marconi got the idea for a practical communications system based on Hertz's work. Marconi was surprised and disappointed that the Italian government was not interested in his newly discovered wireless communications system, and thus he took his equipment to England. From that point on, the wireless became identified with Britain. From these beginnings, wireless radio became the basis of a revolution that has resulted in the satellite communications of today. This history first looks at Marconi's invention and then explores its many applications, including marine radio, cellular telephones, police and military uses, television and radar. Radio collecting is also discussed, and brief biographies are provided for the major figures in the development and use of the wireless.

This handbook is designed to aid electronic warfare and radar systems engineers in making general estimations regarding capabilities of systems. It is not intended as a detailed designer's guide, due to space limitations. Portions of the handbook and future changes will be posted on an internet link.

This book highlights the essential theoretical and practical aspects of lightning, lightning protection, safety and education. Additionally, several auxiliary topics that are required to understand the core themes are also included. The main objective of the contents is to enlighten the scientists, researchers, engineers and social activists (including policy makers) in developing countries regarding the key information related to lightning and thunderstorms. A majority of developing countries are in tropics where the lightning characteristics are somewhat different from those in temperate regions. The housing structures and power/communication networks, and human behavioural patterns(that depends on socio-economic parameters) in these countries are also different from those in the developed world. As the existing books on similar themes address only those scenarios in developed countries, this book serves a vast spectrum of readership in developing world who seek knowledge in the principles of lightning and a practical guidance on lightning protection and safety education.

Direct Energy Conversion discusses both the physics behind energy conversion processes and a wide variety of energy conversion devices. A direct energy conversion process converts one form of energy to another through a single process. The first half of this book surveys multiple devices that convert to or from electricity including piezoelectric devices, antennas, solar cells, light emitting diodes, lasers, thermoelectric devices, and batteries. In these chapters, physical effects are discussed, terminology used by engineers in the discipline is introduced, and insights into material selection is studied. The second part of this book puts concepts of energy conversion in a more abstract framework. These chapters introduce the idea of calculus of variations and illuminate relationships between energy conversion processes.This peer-reviewed book is used for a junior level electrical engineering class at Trine University. However, it is intended not just for electrical engineers. Direct energy conversion is a fascinating topic because it does not fit neatly into a single discipline. This book also should be of interest to physicists, chemists, mechanical engineers, and other researchers interested in an introduction to the energy conversion devices studied by scientists and engineers in other disciplines.