Analog, Digital and Multimedia Telecommunications: Basic and Classic Principles

Analog, Digital and Multimedia

Telecommunications

Basic And Classic Principles

Omar Fakih Hamad

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Copyright © 2011 by Omar Fakih Hamad.

FIRST EDITION

for university and college students

ISBN: Softcover     978-1-4568-1020-7

ISBN: Ebook          978-1-4568-1021-4

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Hamad, Omar Fakih, 1971-

Analog, Digital and Multimedia Telecommunications:

Basic and Classic Principles

This book was printed in the United States of America.

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Dedicated to:

His Excellency Juma Hamad Omar, former principal of Fidel Castro

Secondary School in Zanzibar and former minister in the United

Republic of Tanzania, for his endless efforts in promoting higher

education to intelligent, hardworking, poor students who could,

otherwise, not be able to make it financially!

Contents

Preface

Part I

Analog Telecommunications

Chapter One: Introduction to Telecommunications

1.1 General introduction

1.2 What is telecommunications?

1.3 Very basic telecommunications system

1.4 A telecommunications system with input and output transducers

1.5 Information, messages, and signals

Chapter Two: Signals and Spectra in Telecommunications

2.1 Introduction

2.2 Types of signals in telecommunications

2.3 Spectrum of a signal

2.4 Representation of a periodic signal by the Fourier series

2.5 Complex representation of signal

2.6 Fourier Transforms

2.7 Fourier transform in terms of missing image file

2.8 Fourier transform theorems

2.9 Theorems and transform pairs

2.10 Power Spectral Density

Chapter Three: Liner Continuous Wave (CW) Modulation

3.1 Introduction

3.2 Overview of the modulation methods

3.3 Amplitude modulation (AM)

3.4 The AM spectrum

3.5 AM Transmitter

3.6 AM detection/demodulation

Chapter Four: Exponential Continuous Wave (CW) Modulation

4.1 Introduction

4.3 Frequency modulation (FM)

4.5 Phase demodulation

4.6 De-emphasis and pre-emphasis filtering

Chapter Five: Noise in Telecommunications Systems

5.1 Introduction

5.2 Sources of noise

5.3 Probability density of noise

5.4 Noise in AM systems

5.5 Noise in FM systems

5.6 Comparison of angular and linear modulation systems

5.7 Circuit noise and circuit noise level

Chapter Six: Multiplexing

6.1 Introduction

6.2 Frequency-division multiplexing (FDM)

6.3 Time-division multiplexing (FDM)

6.4 Comparison of TDM and FDM

Chapter Seven: Analog Pulse Modulation

7.1 Introduction

7.2 What is pulse modulation?

7.3 Sampling Theorem

Chapter Eight: Pulse-Code Modulation

8.1 Introduction

8.2 Principle of PCM

8.3 PCM generation and reconstruction

8.3 A PCM receiver

8.4 Quantization noise

8.5 PCM performance

8.6 Advantages of PCM and its applications

Chapter Nine: Data Transmission

9.1 Introduction

9.2 Base-band data transmission

9.3 Error control coding

Part II

Digital Telecommunications

Chapter Ten: Introduction to Digital Telecommunications

10.1 Introduction digital technique

10.3 Basic digital telecommunications nomenclature

10.4 Digital versus analog performance criteria

Chapter Eleven: Pulse Code Modulation (PCM) 11.1 Introduction

11.2 PCM waveform types

11.3 Generation and demodulation of PCM

11.4 Differential PCM

Chapter Twelve: Delta Modulation

12.1 Introduction

12.2 Linear Delta modulation

12.3 Adaptive delta modulation (ADM)

Chapter Thirteen: Phase Shift Keying (PSK)

13.1 Introduction

13.2 Binary Phase-shift keying (BPSK)

13.3 Differential Phase-shift keying (DPSK)

13.4 Differentially-Encoded PSK (DEPSK)

13.5 Quaternary PSK (QPSK)

13.6 Differential QPSK (DQPSK)

13.7 M-ary PSK (MPSK)

Chapter Fourteen: Frequency Shift keying (FSK)

14.1 Introduction

14.2 Binary frequency shift keying (BFSK)

14.3 Comparison of BFSK and BPSK

14.4 M-ary FSK

Chapter Fifteen: Quadrature Amplitude Modulation (QAM)

15.1 Introduction

15.2 QAM as a logical extension of QPSK

15.3 Why do we use QAM (QASK)?

15.4 QASK signal generation

15.5 QASK receiver

Chapter Sixteen: Digital Multiplexing Techniques and Hierarchies

16.1 Introduction

16.2 Digital multiplexing

16.3 Multiplexers and hierarchies

16.4 Major categories of multiplexers

16.5 Multiplexers hierarchies

16.6 The Channel Bank

16.7 Quasi-synchronous Multiplexing

16.8 The AT&T M12 MUX

16.9 Data multiplexers and computer networks

Chapter Seventeen: Information Theory and Coding

17.1 Introduction to communication concepts

17.2 Amount of information

17.3 Entropy and information rate

17.4 Baud rate

17.5 Shannon’s theorem and channel capacity

17.6 Coding, coding efficiency, and error probability

Part III

Multimedia Telecommunications

Chapter Eighteen: Introduction to Multimedia Telecommunications

18.1 Multimedia telecommunications

18.2 Multimedia telecommunications system

18.3 Features for a multimedia telecommunications system

18.4 Basic components of a multimedia telecommunications system

18.5 Data in multimedia telecommunications systems

Chapter Nineteen: Approach to Multimedia Delivery

19.1 Introduction

19.2 Overlay multicast induced packet loss

19.3 Research approach and methodology

Chapter Twenty: Bandwidth-Latency-Product Measures (BLPMs)

20.1 Introduction

20.2 Bandwidth-latency-product formulation and interpretation

Chapter Twenty One: NGS-Based Max-Heap Overlay Multicast Scheme

21.1 Limitations of bandwidth-only-based scheme

21.2 The proposed NGS scheme

21.3 Node gain score (NGS) function

21.4 Logical member positioning in NGSs based overlay

Chapter Twenty Two: Performance Evaluation of Max-Heap Overlay Tree

22.1 Evaluation setup

22.2 Evaluation results and inference

Chapter Twenty Three: Conclusions, Discussion and Possible Future Direction

23.1 Conclusion

23.2 Discussion

23.3 Possible future direction

References

Appendices Tutorials, Quizzes and Tests

Appendix A: Tutorials

A.1 Tutorial One

A.2 Tutorial Two

A.3 Tutorial Three

A.4 Tutorial Four

A.5 Tutorial Five

A.6 Tutorial Six

A.7 Tutorial Seven

A.8 Tutorial Eight

Appendix B: Quizzes

B.1.2 Make-up Quiz One

B.2.1 Quiz Two

B.2.2 Make-up Quiz Two

B.3.1 Quiz Three

B.3.2 Make-up Quiz Three

B.4 Quiz Four

Appendix C: Tests

Preface

In spite the fact that the presentation of this elementary reference book has fetched abundant knowledge and ideas from different sources and people, this book, by itself, is a self referencing piece of work for the beginners and intermediate learners in the field of telecommunications engineering and sciences.

The book has been the result of experiences gained from teaching and learning the materials of the courses—individually and collectively—as analog telecommunications, digital telecommunications and multimedia telecommunications at undergraduate and postgraduate levels.

I am very grateful to the students and the staff for their enormous contributions, motivation and encouragement to make the preparation of this book possible. Many conversations and collaborations with different staff, students and friends in the industry and teaching and learning arenas have been the key success to the book—the success that it owes them big. The direct and indirect encouragements from the head and founder of the telecommunications engineering at the University of Dar es Salaam, Dr. M. M. Kissaka, and the rest of telecommunications engineering staff of putting the materials into a book have been the fundamental inspiration.

The third part of the book, multimedia telecommunications, has been much successful because of the several fruitful discussions that I have had with my friends—seniors and juniors—in Multimedia Data communications Laboratory and specifically very close discussions with my phD professor and supervisor, Dr. Ji seung Nam, of the school of Electronics and computer Engineering at Chonnam National University in the Republic of South Korea.

The real preparation of the manuscript started long back in July 2002 when i started teaching the course to our students at the university of Dar es salaam, and the process continued till in 2010 when the university of Johannesburg, through the Executive Dean of the Faculty of Engineering and the Built Environment, Professor Tshilidzi Marwala, empowered the process through a post doctoral research fellowship and grant offered to me—in collaborationbetween the University of Johannesburg and the South African National Research Foundation (NRF).

This first edition of the book—for university and college students—has been purposely divided into three parts. The basic and classic principles of analog, digital and multimedia telecommunications have been addressed in a simplified manner and without a need of cross-referencing of the encountered equations. That has been done for students to get the direct and inter-related flow of the materials as they read and practice the examples included and those which have been borrowed from other literatures. in addition to the three appendices on tutorials, quizzes and tests, the book has been further divided into twenty three short and manageable chapters including the chapter on conclusions, discussions and future direction on multimedia telecommunications, particularly based on multimedia data delivery challenges.

Part I—Analog Telecommunications—is comprised of nine chapters with Chapter One giving Introduction to Telecommunications; Chapter Two illustrating the need for Signals and Spectra in Telecommunications; Chapter Three on Liner Continuous Wave (CW) Modulation; and Chapter Four devoted to Exponential Continuous Wave (CW) Modulation. Chapter Five is on Noise in Telecommunications Systems; Chapter Six explains Multiplexing; Chapter Seven presents ides on Analog Pulse Modulation; Chapter Eight is about analog based Pulse-Code Modulation; and Chapter Nine touched ideas on Data Transmission.

Part II—Digital Telecommunications—has eight chapters where Chapter Ten gives Introduction to Digital Telecommunications; Chapter Eleven is about digital based Pulse Code Modulation (PCM); Chapter Twelve present principles of Delta Modulation; Chapter Thirteen talks about Phase Shift Keying (PSK); Chapter Fourteen is on Frequency Shift keying (FSK); Chapter Fifteen discusses about Quadrature Amplitude Modulation (QAM); Chapter Sixteen is about Digital Multiplexing Techniques and Hierarchies; and Chapter Seventeen gives detailed discussion on techniques, theories and principles on Information Theory and Coding.

Part III—Multimedia Telecommunications—has six chapters with Chapter Eighteen giving Introduction to Multimedia Telecommunications; Chapter Nineteen discussing the Approach to Multimedia Delivery; Chapter Twenty discussing the Bandwidth- Latency-Product Measures (BLPMs); Chapter Twenty One describing the NGS-Based Max-Heap Overlay Multicast Scheme; Chapter Twenty Two illustrating the Performance Evaluation of Max-Heap overlay Tree; and chapter Twenty Three explaining the Conclusions, Discussion and Possible Future Direction in multimedia delivery techniques.

Omar Fakih Hamad

University of Johannesburg

South Africa

Part I

Analog Telecommunications

Chapter One

Introduction to Telecommunications

1.1 General introduction

Telecommunications, implying electronic communication, defines the science and technology of transmitting information electronically by wires, cables, fibres or radio signals with integrated encoding and decoding equipment. it is about information transmission and switching over communications lines or channels. Technically, information transmission and switching are what make information transfer. it is to be made clear that, at a broader translation, information transfer incorporates both, information transmission and device switching. Nevertheless, in this elementary and introductory edition of the subject, the two will be, and can be, used interchangeably and sometimes complementing each other.

With that basic definition in mind, the telecommunications engineer’s main concern is confined within transmission reception of information signals. By a signal, we mean an electric voltage or current which varies with time and is used to carry messages or information from one point to another. The form of a message in telecommunications engineering can be either in word or coded symbols. However, of great importance in telecommunications is the amount of information the message contains.

But why are we interested in converting information into a signal? it is mainly because it is more convenient to handle information as signal. Through transmission channels, the signal is easily transmitted over a communication system where, at the destination, the signal can then be transformed back to the original information or message.

1.2 What is telecommunications?

In basic electric sense, telecommunications is the sending, receiving, and processing of information by electric means. The evolution of telecommunications and its use emerged as early as in the dates before the nineteenth century, but the documentation started in 1840s with wire telegraphy coming into use. The invention of telephony was observed in the 1870s while in 1900s the field had enjoyed the birth of radio technologies with triode tube which made a great use in WWII. The success gained during the WWii made the field to be widely used further and more refined through the invention of the transistor and the use of the transistor, iC, and other semiconductor devices.

More recently, the use of satellites and fibre optics has made telecommunications more widespread with increasing emphasis on computer and other data communications devices. A modern telecommunications system is concerned with the sorting, the processing, the storing, transmission, further processing, the filtering of noise and the reception with the processing steps including decoding, storage, and interpretation of the signals into real world data.

The forms of telecommunications include radio telephony and telegraphy, broadcasting, point-to-point, mobile communications, computer communications, radar systems, radio-telemetry and radio aids to navigation, and so many others emerging technologies like overlay multicasting and peer-to-peer multimedia sharing over the internet.

Telecommunications background empathizes on proper and adequate understanding of the operations of amplifiers and oscillators, the building blocks of them, and the electronic processes and equipment involved. it is also important to understand the daily telecommunications concepts like noise, modulation, and information theory. Logically, it is a wise and suitable idea to considered basic systems, communications process and circuits, and more complex systems and in that order.

1.3 Very basic telecommunications system

Considering the fact that telecommunications is about sending, processing and receiving of information from a source to at least one destination, Fig. 1.1 depicts a very basic telecommunications system an information source and a destination exchanging information via a communication channel.

Fig. 1.1. A very basic telecommunications system

At the source, the message signals are generated for the transmitter where the transmitter process the signals and send them along the transmission line or channel to the receiver. The receiver extracts the messages and sends tem to their final destination or sink. During the process, the noise is picked up from various sources during transmission and reception.

1.4 A telecommunications system with input and output transducers

Fig. 1.2. Elements of a telecommunication system in a voice communication system

Fig. 1.2 describes a typical telecommunications system in a voice communication system where we need to have an input transducer which can be thought of as7, and in fact it is, a microphone, while the output transducer can be a conventional loud speaker

Fig. 1.3. A telecommunication system with input and output transducers

Fig. 1.3 shows a more generalized telecommunications system with all the basic elements and the external noise environment shown with its effects towards the whole system. It is shown that source of information itself might be a contributor towards the system’s overall nose. The source submits the real world like information to an input transducer whereby the transducer itself might also have some effects to noise contribution. The telecommunications transmitter accepts the signals to transmission channel which, along with the noise from the transmitter, it has its own sources of noise affecting the transmission. The received signals from the channel are accepted by the telecommunications receiver before transforming the signals into output transducer compatible format ready to be sent to the information destination which might also have some contributions towards the overall performance of the received information.

Three essential parts of any telecommunications system are unavoidable. These are the transmitter, the transmission channel, and the receiver. The transmitter processes the input signal to produce a transmitted signal suited to the characteristics of the transmission channel. Therefore, signal transmission involves modulation and coding. The transmission channel is basically the electrical or rather electromagnetic medium that bridges the distance from source to destination, that is, transmitter to receiver. This may be a pair of wires, a coaxial cable, a radio wave, laser beam, or an optical fibre. Every channel experiences some amount of transmission loss which we refer as attenuation. In addition, it is known that signal power is inversely proportional to the transmission distance, that is, it can expressed as in Eq. (1.1): -

Therefore, the receiver is dealing with the preparation for delivery to the destination. The receiver operations include amplification, demodulation, decoding, and filtering. Nevertheless, telecommunications systems will always experience attenuation, noise distortion, and interference. While attenuation reduces signal strength at the receiver, on one side, noise, distortion, and interference, on the other hand, lead to alteration of the signal shape. Even though, there might be several known sources of this, the convention is to blame them entirely on the channel.

1.5 Information, messages, and signals

Information in telecommunications signifies semantic and philosophical notions that defy precise definition while message implies physical manifestation of information as produced by the source. Signals are the detectable electrical pulses representing messages or information. They are in voltage or current form. Signal and message are sometimes used interchangeably. They are both physical embodiment of information.

Chapter Two

Signals and Spectra in Telecommunications

2.1 Introduction

Signals, meant in telecommunications, are time-varying quantities such as voltages and currents, which are used to carry information from a point to another. Although signals physically exist in the time domain, they can also be represented in frequency domain. This means that, signals can be viewed as consisting of sinusoidal components at various frequencies.

Spectrum is in short the frequency domain description of the signal. Spectral analysis is customarily done by Fourier series and Fourier Transform. The analysis makes the fundamental method of telecommunications engineering. it allows one to treat entire classes of signals that have similar properties in the frequency domain avoiding detailed time domain analysis of individual signals. The spectral analysis approach provides valuable insight for design work in telecommunications systems. Therefore, it is advised that a special attention to the frequency domain interpretation of signal properties must be given.

2.2 Types of signals in telecommunications

There are two main types of signals—the analogue signals which vary continuously with time and the digital signals which are discontinuous with time.

2.2.1. Analogue signals

Usually, analog signals represent the variation of a physical quantity. Example includes a sound wave. They are either single sine waves or a combination of them. A simple analogue signal is shown in Fig. 2.1 where the voltage quantity V varies continuously with time t.

Fig.2.1. A simple analogue signal

Fig.2.2. Analogue signal

An example depicted in Fig.2.1 shows certain nature of uniformity and predictability, but in Fig.2.2 the example of analogue signal is shown where by the quantity on the vertical line, be it current or voltage against time t, can not predicted