Modern Communications Technology

Natasa Zivic

• Publisher: De Gruyter Oldenbourg
• Year: 2016
• Print ISBN: 9783110413373
• eBook ISBN: 9783110423907
• Edition: 1
• Topic: Technology & Engineering
• Subtopic: Signals & Signal Processing
• Index: Technology & Engineering

The book explains in a comprehensive way the basic terms of communication engineering, giving a proper amount of the needed mathematical background and explanations of the physical nature of the problems. The theory of communication sciences is explained by using knowledge and examples from real-world applications. The information is presented in a way that is understandable also for those who are not directly involved in communication sciences, but would like to learn more about them.

1Signals and Systems

1.1Communication System

Signals are electrical equivalents of data to be transmitted through a communication system. A complete communication system consists of two stations, each equipped with a transmitter and a receiver, or combined into a single device called transceiver (Fig. 1.1). The medium of signal transmission can be wired (see Chapter 7) or wireless (see Chapter 8).

Fig. 1.1: Elements of communication system.

A data station consists of a Data Terminal Equipment (DTE) and a Data Circuit Terminating Equipment (DCE). DTE converts user data into signals or reconverts received signals into user data. DCE is intermediate equipment between DTE and a data transmission circuit (Fig. 1.2).

The boundary between DTE and DCE is called interface and is defined according to the properties of transmission lines and exchanged signals between DTE and DCE. Intermediate devices (e.g. error control device, synchronization devices etc.) can be added into interfaces. Generally, an interface is also a boundary for performance and achievement of a network provider, his ownership and responsibility. Interfaces are internationally standardized, e.g. by ITU-T:

–	V:	Data Communication over the telephone network (e.g. V.24/V.28, V.10, V.11)
–	X:	Data networks, open system communications and security (e.g. X.20, X.21, X.25, X.26, X.27)
–	I:	Integrated Services Digital Network (ISDN)
–	G:	Transmission systems in media, digital systems and networks
–	H:	Audiovisual and multimedia systems
–	T:	Terminals for telematic services
–	Z:	Languages and general software aspects for telecommunication systems
–	etc.

Fig. 1.2: Elements of data station.

A DTE is a functional unit serving as a data source or a data sink and providing control function for data communication accordingly to the link protocol. A DTE can be a user himself or a device interacting with user, e.g. through a human-machine interface. DTE consists of:

–Data source or data sink in a form of data producers (input devices), data processing devices and data consumers (output devices).

–Controller with data preparation device, parallel-serial converter and serial-parallel converter, error control device, address recognizer end device, synchronizer device, sending or receiving part, management and data transmission control.

Examples of DTEs are terminals, memories, keyboards, printers, data concentrators and computers.

A DCE (also called Data Communication Equipment and Data Carrier Equipment) performs functions such as: line clocking, conversion of signals from DTE in corresponding form for transmission (line coding and modulation, see Chapter 5) and, the opposite, conversion of transmitted si...

Table of contents

• Cover
• Title Page
• Copyright
• Special Thanks
• Foreword
• Contents
• 1 Signals and Systems
• 2 Typical Communications Signals
• 3 Random Processes
• 4 Information Theory and Coding
• 5 Digital Transmission
• 6 Multiplexing
• 7 Wired Transmission Media
• 8 Wireless Channel
• 9 Cryptography
• References
• List of Acronyms
• Index
• Endnotes