Modulation Theory

Modulation Theory

In recent years, a considerable amount of effort has been devoted, both in industry and academia, towards the design, performance analysis and evaluation of modulation schemes to be used in wireless and optical networks, towards the development of the next and future generations of mobile cellular communication systems. Modulation Theory is intended to serve as a complementary textbook for courses dealing with Modulation Theory or Communication Systems, but also as a professional book, for engineers who need to update their knowledge in the communications area. The modulation aspects presented in the book use modern concepts of stochastic processes, such as autocorrelation and power spectrum density, which are novel for undergraduate texts or professional books, and provides a general approach for the theory, with real life results, applied to professional design. This text is suitable for the undergraduate as well as the initial graduate levels of Electrical Engineering courses, and is useful for the professional who wants to review or get acquainted with the a modern exposition of the modulation theory. The book covers signal representations for most known waveforms, Fourier analysis, and presents an introduction to Fourier transform and signal spectrum, including the concepts of convolution, autocorrelation and power spectral density, for deterministic signals. It introduces the concepts of probability, random variables and stochastic processes, including autocorrelation, cross-correlation, power spectral and cross-spectral densities, for random signals, and their applications to the analysis of linear systems. This chapter also includes the response of specific non-linear systems, such as power amplifiers. The book presents amplitude modulation with random signals, including analog and digital signals, and discusses performance evaluation methods, presents quadrature amplitude modulation using random signals. Several modulation schemes are discussed, including SSB, QAM, ISB, C-QUAM, QPSK and MSK. Their autocorrelation and power spectrum densities are computed. A thorough discussion on angle modulation with random modulating signals, along with frequency and phase modulation, and orthogonal frequency division multiplexing is provided. Their power spectrum densities are computed using the Wiener-Khintchin theorem.

Modulation Theory

General Airgap Field Modulation Theory for Electrical Machines

General Airgap Field Modulation Theory for Electrical Machines Introducing a new theory for electrical machines Air-gap magnetic field modulation phenomena have been widely observed in electrical machines. This book serves as the first English-language overview of these phenomena, as well as developing systematically for the first time a general theory by which to understand and research them. This theory not only serves to unify analysis of disparate electrical machines, from conventional DC machines, induction machines, and synchronous machines to unconventional flux-switching permanent magnet machines, Vernier machines, doubly-fed brushless machines etc., but also paves the way towards the creation of new electrical machine topologies. General Airgap Field Modulation Theory for Electrical Machines includes both overviews of key concepts in electrical machine engineering and in-depth specialized analysis of the novel theory itself. It works through the applications of the developed theory before proceeding to both qualitative analysis of the theory’s operating principles and quantitative analysis of its parameters. Readers will also find: The collective experience of four award-winning authors with long records of international scholarship on this subject Three separate chapters covering the principal applications of the theory, with detailed examples Discussion of potential innovations made possible by this theory General Airgap Field Modulation Theory for Electrical Machines is an essential introduction to this theory for postgraduates, researchers, and electrical engineers.