Design and Performance of a Spread Spectrum Data Communications System Using Delta Modulation with a Dithered Clock

Design and Performance of a Spread Spectrum Data Communications System Using Delta Modulation with a Dithered Clock PDF Author: Evangelos Vassilios Pappas
Publisher:
ISBN:
Category : Delta modulation
Languages : en
Pages : 98

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Book Description
Digital modulation schemes and spread spectrum techniques are of major importance in modern communications. This thesis investigates a delta modulation/demodulation scheme and direct sequence spreading of the digital data. The clock rate is dithered to enhance the low probability of intercept advantage of spread spectrum. The circuitry incorporates small and medium scale integrated circuits. Experimental results are presented in some detail. Good quality voice and music were recovered using a fixed bit rate as low as 10 kbits/sec and a clock dither range of 40%. (Author).

Design and Performance of a Spread Spectrum Data Communications System Using Delta Modulation with a Dithered Clock

Design and Performance of a Spread Spectrum Data Communications System Using Delta Modulation with a Dithered Clock PDF Author: Evangelos Vassilios Pappas
Publisher:
ISBN:
Category : Delta modulation
Languages : en
Pages : 98

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Book Description
Digital modulation schemes and spread spectrum techniques are of major importance in modern communications. This thesis investigates a delta modulation/demodulation scheme and direct sequence spreading of the digital data. The clock rate is dithered to enhance the low probability of intercept advantage of spread spectrum. The circuitry incorporates small and medium scale integrated circuits. Experimental results are presented in some detail. Good quality voice and music were recovered using a fixed bit rate as low as 10 kbits/sec and a clock dither range of 40%. (Author).

Multi-Carrier and Spread Spectrum Systems

Multi-Carrier and Spread Spectrum Systems PDF Author: Khaled Fazel
Publisher: John Wiley & Sons
ISBN: 0470714239
Category : Technology & Engineering
Languages : en
Pages : 384

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Book Description
The technological progress in multi-carrier (MC) modulation led orthogonal frequency division multiplexing (OFDM) to become an important part of beyond 3G cellular mobile communication standards, including LTE and WiMAX. In addition, the flexibility offered by the spread spectrum (SS) and time division multiplexing (TDM) techniques motivated many researchers to investigate several MC combined multiple access schemes, such as MC-CDMA, OFDMA and MC-TDMA. These schemes benefit from the advantages of each sub-system and offer high flexibility, high spectral efficiency, simple detection strategies and narrow-band interference rejection capability. Multi-Carrier and Spread Spectrum Systems is one of the first books to describe and analyze the basic concepts of multi-carrier OFDM transmission and its combination with spread spectrum (MC-CDMA). The different architectures and detection strategies as well as baseband-related transceiver components are explained. This includes topics like FEC channel coding and decoding, modulation and demodulation (IFFT/FFT), digital I/Q-generation, time and frequency synchronisation, channel estimation, frequency domain equalization and RF aspects such as phase noise and non-linearity issues. Concrete examples of its applications for cellular mobile communication systems (B3G/4G) are given. Further derivatives of MC-SS (such as OFDMA, SS-MC-MA and DFT-spread OFDM) and their corresponding applications in the LTE, WiMAX, WLAN and DVB-RCT standards are detailed. Capacity and flexibility enhancements of multi-carrier OFDM systems by different MIMO diversity techniques such as space time/frequency coding (STC, SFC) and software defined radio concepts are also described. Written in a highly accessible manner this book provides a unique reference on the topics of multi-carrier and spread spectrum communications, assisting 4G engineers with their implementation. Fully updated new edition of successful text, including two new chapters on LTE and WiMAX Describes in detail new applications of OFDM in mobile communication standards Examines all multi-carrier spread spectrum schemes, with in-depth analysis, from theory to practice Introduces the essentials of important wireless standards based on multi-carrier/spread spectrum techniques.

Fundamentals of Spread Spectrum Modulation

Fundamentals of Spread Spectrum Modulation PDF Author: Rodger E. Ziemer
Publisher: Morgan & Claypool Publishers
ISBN: 1598292641
Category : Digital modulation
Languages : en
Pages : 87

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Book Description
This lecture covers the fundamentals of spread spectrum modulation, which can be defined as any modulation technique that requires a transmission bandwidth much greater than the modulating signal bandwidth, independently of the bandwidth of the modulating signal. After reviewing basic digital modulation techniques, the principal forms of spread spectrum modulation are described. One of the most important components of a spread spectrum system is the spreading code, and several types and their characteristics are described. The most essential operation required at the receiver in a spread spectrum system is the code synchronization, which is usually broken down into the operations of acquisition and tracking. Means for performing these operations are discussed next. Finally, the performance of spread spectrum systems is of fundamental interest and the effect of jamming is considered, both without and with the use of forward error correction coding. The presentation ends with consideration of spread spectrum systems in the presence of other users. For more complete treatments of spread spectrum, the reader is referred to [1, 2, 3].

Design and Performance of a Frequency Hopping Communications System Using Delta Modulation

Design and Performance of a Frequency Hopping Communications System Using Delta Modulation PDF Author: Habib Kucukoglu
Publisher:
ISBN:
Category :
Languages : en
Pages : 53

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Book Description
A way to increase jamming immunity and to decrease the intercept probability of a communication system is to use spread spectrum (SS) techniques. In this report a frequency hopping SS system (transmitter and receiver) is presented. This system is designed, built, and tested to send and receive digitized voice by utilizing a single chip delta modulator/demodulator. The report describes the circuitry employed, lists the important parameters of the system and includes photographs of various waveforms. The recovered audio is of good quality using digital data rates as low as 25 kilobits per second. A hopping rate of 100 hops per second is used in the design. (Author).

Perspectives in Spread Spectrum

Perspectives in Spread Spectrum PDF Author: Amer A. Hassan
Publisher: Springer Science & Business Media
ISBN: 9780792382652
Category : Technology & Engineering
Languages : en
Pages : 178

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Book Description
Perspectives in Spread Spectrum brings together studies and recent work on six exciting topics from the spread spectrum arts. The book gives a wide, collective view of trends, ideas, and techniques in the spread spectrum discipline, due to the authors' extensive work on spread spectrum techniques and applications from different vantage points. The inexorable march of electronics towards ever faster, ever smaller, and ever more powerful electronic and optical circuitry has wrought, and will continue to enable, profound changes in the spread spectrum arts, by allowing increasingly complex signalling waveforms and statistical tests to be implemented as the theory beyond spread spectrum continues to evolve. Perspectives in Spread Spectrum is divided into six chapters. The first chapter deals with sequence spreading design. There is not a single metric for design of spreading sequences; rather, the design is ideally tailored to the specific scenario of usage. This chapter delves into recent and very promising synthesis work. The second chapter deals with OFDM techniques. As channels become wider and trans-channel fading (or jamming) becomes frequency selective across the band, OFDM techniques may provide a powerful alternative design perspective. The third chapter is a generalization of the venerable Walsh functions. A new modulation scheme, Geometric Harmonic Modulation, GHM for short, is reviewed and characterized as a form of OFDM. From GHM, a further generalization of the Walsh functions is derived for non-binary signalling. The fourth chapter is concerned with some new and exciting results regarding the follower jammer paradigm. A counter-countermeasure technique is reviewed, notable for its counterintuitive characteristic which can be understood from a simple yet elegant game framework. The fifth chapter recounts some results pertaining to random coding for an optical spread spectrum link. The technique is based on laser speckle statistics and uses a coherent array of spatial light modulators at the transmitter but allows the receiver to be realized as a spatially distributed radiometric and therefore incoherent structure. The sixth and final chapter looks at an important and interesting application of spread spectrum to accurately locate a wideband, ‘bent pipe’, satellite transponder. It is, in a strong sense, an inverted GPS technique. Perspectives in Spread Spectrum serves as an excellent reference and source of ideas for further research, and may be used as a text for advanced courses on the topic.

Design and Performance of a Frequency Hopping Communications System Using Delta Modulation

Design and Performance of a Frequency Hopping Communications System Using Delta Modulation PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
A way to increase jamming immunity and to decrease the intercept probability of a communication system is to use spread spectrum (SS) techniques. In this report a frequency hopping SS system (transmitter and receiver) is presented. This system is designed, built, and tested to send and receive digitized voice by utilizing a single chip delta modulator/demodulator. The report describes the circuitry employed, lists the important parameters of the system and includes photographs of various waveforms. The recovered audio is of good quality using digital data rates as low as 25 kilobits per second. A hopping rate of 100 hops per second is used in the design. (Author).

Spread Spectrum and CDMA

Spread Spectrum and CDMA PDF Author: Valeri P. Ipatov
Publisher: John Wiley & Sons
ISBN: 0470091797
Category : Science
Languages : en
Pages : 396

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Book Description
Spread spectrum and CDMA are cutting-edge technologies widely used in operational radar, navigation and telecommunication systems and play a pivotal role in the development of the forthcoming generations of systems and networks. This comprehensive resource presents the spread spectrum concept as a product of the advancements in wireless IT, shows how and when the classical problems of signal transmission/processing stimulate the application of spread spectrum, and clarifies the advantages of spread spectrum philosophy. Detailed coverage is provided of the tools and instruments for designing spread spectrum and CDMA signals answering why a designer will prefer one solution over another. The approach adopted is wide-ranging, covering issues that apply to both data transmission and data collection systems such as telecommunications, radar, and navigation. Presents a theory-based analysis complemented by practical examples and real world case studies resulting in a self-sufficient treatment of the subject Contains detailed discussions of new trends in spread spectrum technology such as multi-user reception, multicarrier modulation, OFDM, MIMO and space-time coding Provides advice on designing discrete spread spectrum signals and signal sets for time-frequency measuring, synchronization and multi-user communications Features numerous Matlab-based problems and other exercises to encourage the reader to initiate independent investigations and simulations This valuable text provides timely guidance on the current status and future potential of spread spectrum and CDMA and is an invaluable resource for senior undergraduates and postgraduate students, lecturers and practising engineers and researchers involved in the deployment and development of spread spectrum and CDMA technology. Supported by a Companion website on which instructors and lecturers can find a solutions manual for the problems and Matlab programming, electronic versions of some of the figures and other useful resources such as a list of abbreviations.

Spread Spectrum in Communication

Spread Spectrum in Communication PDF Author: Reidar Skaug
Publisher: IET
ISBN: 9780863410345
Category : Technology & Engineering
Languages : en
Pages : 228

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Book Description
The book is devoted to advanced radiocommunication, discussing the merits and operational aspects of spread spectrum signalling. Spread spectrum modulation is emerging as one of the most important tools for combatting a wide range of problems usually encountered in radiocommunication. For military applications the signalling is able to resist difficulties deliberately introduced by an enemy, such as jamming and eavesdropping. For civil application, the efficient signal multiplexing and multipath rejection capability is of great interest. The price paid however is the need for very complex processing of the radio signals. This task put great challenges on new technologies and design, and it is only recently that operational systems have started to emerge from the laboratories. The book starts by comparing spread spectrum modulation and conventional modulation methods, and then discusses demodulation, which requires both special acquisition and synchronisation techniques. The electronic warfare scenario is introduced, discussing the principles of various spreading techniques and possible countermeasures. The coding for bandwidth spreading in a direct sequence spread spectrum system is treated by discussing the most common codes and their different figures of merit with respect to multipath, code division multiplexing and signal concealment. The book also illustrates the possible benefits, as well as limits to the use of new hardware technology to accomplish the various functions necessary for successful operation of a spread spectrum system. The effect of the propagation environment on spread spectrum is treated both analytically and through reported experiments and simulations. Finally the book considers the task of designing a complete communication network and discusses the usefulness and technology for additional interference suppressing techniques suitable to work with spread spectrum systems.

Spread Spectrum Systems

Spread Spectrum Systems PDF Author: Robert Clyde Dixon
Publisher: Wiley-Interscience
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 344

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Book Description


Scientific and Technical Aerospace Reports

Scientific and Technical Aerospace Reports PDF Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 1074

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Book Description