COMPRESSION TECHNIQUES

Transcription

1 Table of Contents Preface xvii INTRODUCTION Introduction A little bit of history Information Digital versus analogue Conversion to digital Sampling theory Quantization Exercises 13 COMPRESSION TECHNIQUES Introduction Compression methods Letter probabilities Coding methods Statistical encoding Repetitive sequence suppression Differential encoding Transform encoding Exercises Letter probablity program 27 HUFFMAN/LEMPEL-ZIV COMPRESSION METHODS Introduction Huffman coding Adaptive Huffman coding Lempel-Ziv coding Lempel-Ziv-Welsh coding Variable-length-code LZW compression Disadvantages with LZ compression Practical Lempel-Ziv/Huffman coding Exercises 37

2 viii Contents IMAGE COMPRESSION (GIF/TIFF/ PCX) Introduction Comparison of the different methods GIF coding TIFF coding GIF interlaced images PCX coding Exercises 60 IMAGE COMPRESSION (JPEG) Introduction JPEG coding JPEG decoding JPEG file format JPEG modes Exercises 79 VIDEO SIGNALS Introduction Color-difference signals Quadrature modulation Baseband video signals Digitizing TV signals Hz pictures Compressed TV HDTV quality Exercise 95 MOTION VIDEO COMPRESSION Motion video MPEG-1 overview MPEG-1 video compression MPEG-1 compression process MPEG-1 decoder MPEG-1 audio compression MPEG MPEG-2 system layer Other MPEG-2 enhancements MPEG-2 bit rate Exercises 109 SPEECH AND AUDIO SIGNALS Introduction PCM parameters 111

3 Contents ix 8.3 Differential encoding Speech compression A-Law and µ-law companding Speech sampling PCM-TDM systems Exercises 126 AUDIO SIGNALS Introduction Principles Digital audio standards Error control Interleaving CD audio system Digital audio compression The 44.1 khz sampling rate Exercise 142 AUDIO COMPRESSION (MPEG-AUDIO AND DOLBY AC-3) Introduction Psycho-acoustic model MPEG audio coding Backward/forward adaptive bit allocation methods Comparison between forward and backward adaptive methods Dolby AC-1 and AC Dolby AC-3 coding AC-3 parameters Exercises 157 ERROR CODING PRINCIPLES Introduction Modulo-2 arithmetic Binary manipulation Hamming distance General probability theory Error probability Combinations of errors Linear and cyclic codes Block and convolutional coding Systematic and unsystematic coding Feedforward and feedback error correction Error types Coding gain Exercises 172

4 x Contents ERROR CODING (DETECTION) Introduction Parity Block parity Checksum Cyclic redundancy checking (CRC) Exercises 183 ERROR CODING (CORRECTION) Introduction Longitudinal/vertical redundancy checks (LRC/VRC) Hamming code Representations of Hamming code Single error correction/double error detection Hamming code Reed-Solomon coding Convolution codes Tutorial 202 DATA ENCRYPTION PRINCIPLES Introduction Government pressure Cryptography Legal issues Basic encryption principles Exercises 215 DATA ENCRYPTION Introduction Private-key encryption Public-key encryption Exercises 229 TCP/IP Introduction TCP/IP gateways and hosts Function of the IP protocol Internet datagram ICMP TCP/IP internets Domain name system Internet naming structure Domain name server Bootp protocol Example network 245

5 Contents xi Exercises 248 TCP/IP II Introduction IP Ver Transmission control protocol TCP/IP commands Exercises 260 ELECTRONIC MAIL Introduction Shared-file approach versus client/server approach Electronic mail overview Internet address SMTP X MIME Exercises 282 THE WORLD WIDE WEB Introduction Advantages and disadvantages of the WWW Client/server architecture Web browsers Internet resources Universal resource locators (URLs) Universal resource identifier Intranets Firewalls Exercises 299 HTTP Introduction HTTP operation Intermediate systems Cache HTML messages Exercises 309 HTML (INTRODUCTION) Introduction Links Lists Colors 319

6 xii Contents 21.5 Background images Displaying images Horizontal lines Exercises 325 HTML (TABLES, FORMS AND HELPERS) Introduction Anchors Tables CGI scripts Forms Multimedia Exercises 341 JAVA/JAVASCRIPT Introduction JavaScript JavaScript values, variables and literals Expressions and operators JavaScript operators JavaScript statements Conditional statements Loops Comments Functions Objects and properties Document objects Event handling Object manipulation statements and operators Exercises 367 WINDOWS NT Introduction Novell NetWare networking Servers, workstations and clients Workgroups and domains User and group accounts New user accounts File systems Windows NT networking Setting up TCP/IP networking on Windows NT Windows sockets Network dynamic data exchange (Net DDE) Robust networking Security model 385

7 Contents xiii TCP/IP applications Windows NT network drives Exercises 388 NETWARE Novell NetWare networking NetWare and TCP/IP integration NetWare architecture NetWare protocols IPX Novell NetWare setup NetWare Exercises 407 UNIX Introduction Network setup TCP/IP protocols NFS Network configuration files Sample startup file Exercises 420 NETWORKING ELEMENTS LANs, WANs, and MANs OSI model Communications standards and the OSI model Standards agencies Network cable types LAN topology Internetworking connections Internet routing protocols Network topologies Network loading Exercises 443 ETHERNET Introduction IEEE standards Ethernet - media access control (MAC) layer IEEE and Ethernet SNAP OSI and the IEEE standard Ethernet transceivers NIC Standard Ethernet limitations 457

8 xiv Contents 28.9 Ethernet types Twisted-pair hubs Mbps Ethernet Ethernet security Exercises 468 TOKEN RING Introduction Operation Token Ring - media access control (MAC) Token Ring maintenance Token Ring multistation access units (MAUs) Cabling and connectors Repeaters Jitter suppression Exercise 477 FDDI Introduction Operation FDDI layers SMT protocol Physical connection management Fault tolerance method FDDI token format FDDI Frame format MAC protocol Applications of FDDI networks FDDI backbone network FDDI attachments FDDI media FDDI specification FDDI-II Standards Practical FDDI network EaStMAN Exercises 495 ASYNCHRONOUS TRANSFER MODE (ATM) Introduction Real-time sampling PCM-TDM systems and ISDN Objectives of ATM ATM versus ISDN and PCM-TDM Statistical multiplexing ATM user network interfaces (UNIs) 502

9 Contents xv 31.8 ATM cells Routing cell within an ATM network Virtual channels and virtual paths ATM and the OSI model ATM physical layer AAL service levels ATM flow control Practical ATM networks Tutorial 513 INTEGRATED SERVICES DIGITAL NETWORK (ISDN) Introduction ISDN channels ISDN physical layer interfacing ISDN data link layer ISDN network layer Exercises 526 MODEMS Introduction RS-232 communications Modem standards Modem commands Modem setups Modem indicators Digital Modulation Typical modems Fax transmission Exercises 543 ASCII CODING 545 A.1 International alphabet No A.2 Extended ASCII code 547 A.3 RS-232C interface 549 A.4 RS-449 interface 549 CABLE SPECIFICATIONS 551 B.1 Introduction 551 RLE PROGRAM 557 C.1 RLE program 557

10 xvi Contents SNR FOR PCM 561 D.1 SNR 561 RFC STANDARDS 563 UNIX NETWORK STARTUP FILES 567 F.1 netnfsrc file 567 F.2 rc file 571 ETHERNET MONITORING SYSTEM 577 G.1 Ethernet receiver 577 ENCRYPTION 579 H.1 Cracking the code 579 H.2 Random number generators 579 H.3 Survey of private-key cryptosystems 580 H.4 Public-key cryptosystems 582 DIGITAL LINE GROUP CODES 583 I.1 Line codes 583 I.2 NRZI 583 I.3 DSV 585 I.3 4B5B 585 I.3 EFM 586 I.3 5B6B 587 I.3 8B6T 588 I.3 8/10 code 589 COMMON ABBREVIATIONS 553 Index 601

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