الفهرس | Only 14 pages are availabe for public view |
Abstract The introduction chapter (1) discusses important topics for ultra wideband (UWB) technology. The definition of UWB is given. Advantages of UWB technology are discussed in detail. Shaping of UWB signals is presented. FCC frequency masks are given. Modulation and multiple access techniques are discussed in detail. The properties of signals required for on-body communications are presented. Organization of the material in the thesis is given. Chapter 2 deals with Gaussian signals. The chapter starts with studying the prohibited signal, which is damped sinusoidal signal. Then the Gaussian signal and its derivatives are discussed. Types of UWB signals; impulse-UWB and multi-carrier UWB, are presented. Multiband modulation is discussed in detail and used to overcome the interference with narrow band systems occupying the same frequency band. Finally, the chapter concludes with a developed design procedure that produces a signal that follows closely the FCC mask. Hermite polynomials are discussed in chapter 3. Hermite pulses are modified to get orthogonal signals. Modified Hermite pulses are modulated to get more flexibility in the frequency domain. The autocorrelation function of the modified modulated pulses is computed. An algorithm is developed to design complex signal based upon modulated modified Hermite pulses that complies with the FCC mask. Chapter 4 is concerned with Chirp signals. Linear and non-linear, up- and down-Chirp signals are presented. The waveform, frequency spectrum and autocorrelation function are shown for each signal. An algorithm is developed to design a composite signal based on nonlinear down Chirp signal. Chapter 5 deals with Prolate spheroidal signals. An algorithm is developed to generate a signal limited in time to increase data rate and system capacity and limited in frequency. A composite signal is generated that complies closely with FCC mask. Conclusions and suggestions of future work are given in chapter 6. The appendix includes the MATLAB programs developed for the design of different signals. |