数字与模拟通信系统 第5版PDF电子书下载

1 INTRODUCTION 1

1-1 Historical Perspective 2

1-2 Digital and Analog Sources and Systems 2

1-3 Deterministic and Random Waveforms 6

1-4 Organization of This Book 6

1-5 Use of a personal Computer and MATLAB 7

1-6 Block Diagram of a Communication System 8

1-7 Frequency Allocations 9

1-8 Propagation of Electromagnetic Waves 10

1-9 Information Measure 16

Example1-1 Evaluation of information and Entropy, 17

1-10 Channel Capacity and ldeal Communication Systems 18

1-11 Coding 19

Block Codes 21

Convolutional Codes. 21

Code interleaving. 23

Code performance. 24

Trellis-Coded Modulation. 27

1-12 Preview 30

1-13 Study-aid Examples 30

Problems 31

2 SIGNALS AND SPECTRA 33

2-1 Properties of Signals and Noise 33

Physically Realizable Waveforms. 34

Time Average Operator. 35

Dc Value. 36

Power. 37

Example2-1 Evaluation of Power. 38

Rms Value and Normalized Power. 39

Energy and Power Waveforms. 40

Decibel. 40

Phasors. 42

2-2 Fourier Transform and Spectra 43

Definition. 43

Example2-2 Spectrum of an Exponentiat Pulse. 45

Propertise of Fourier Transforms. 46

Parseval s Theorem and Energy Spectral Density. 47

Example2-3 Spectrum of a Damped Sinusoid. 49

Dirac Data Function and Unit Step Function, 50

Example2-4 Spectrum of a Sinusold. 52

Rectangular and Triangular-Pulses. 54

Example2-5 Spectrum of a Rectangular Pulse. 54

Example2-6 Spectrum of a Triangular Pulse. 57

Convolution. 58

Example2-7 Convolution of a Rectangle with an Exponential,. 58

Example2-8 Spectum of a Triangular Pulse by Convotution,. 59

Example2-9 Spectrum of a Switched Sinusoid. 60

2-3 Power Spectral Density and Autocorrelation Function 62

Power Spectral Density. 62

Autocotrelation Function. 63

Example2-10 PSD of a Sinusoid. 63

2-4 Orthogonal Series Representation of Signals and Noise 65

Orthogonal Functions. 65

Example2-11 Orthogonal Complex Exponential Functions. 66

Orthogonal Series. 66

2-5 Fourier Series 68

Complex Fourier Series. 68

Quadrature Fourier Series. 70

Polar Fourier Series. 71

Line Spectra for Periodic Waveforms. 73

Example2-12 Fourier Coefficienis for a Rectangular Wave, 75

Power Spectral Density for Periodic Waveforms. 76

Example2-13 PSD for a Square Wave. 77

2-6 Review of Linear Systems 78

linecr Time-Invariont Systems. 78

Impulse Response. 79

Tnmifer Fwtction. 79

Example2-14 RC Low-Pass Filter. 81

Distortionless Transmission 83

Example2-15 Distortion Caused by a Filter. 83

2-7 Bandlimited Signals and Noise 84

Bandlimited Waveforms. 86

Sampling Theorem. 86

Impulse Sampling. 89

Dimensionolity Theorem. 92

2-8 Discrete Fourier Transform 93

Using the DFT to Compute the Contisuous Fourier Transform. 94

Example2-16 DFT for a Rectangular pulse. 97

Using the DFT to Compute the Fourier Series. 100

Example2-17 Use the DFT to Compute the Spectrum of a Sinusoid 100

2-9 Bandwidth of Signals 101

Example2-18 Bandwidths for a BPSK Signal. 105

2-10 Summary 109

2-11 Study-Aid Examples 110

Problems 113

3 BASEBAND PULSE AND DIGIIAL SIGNALING 127

3-1 Introduction 127

3-2 Pulse Amplitude Modulation 128

Natural Sampling (Gating). 129

Instantaneous Sampling(Flat-Top PAM). 133

3-3 Pulse Code Modulation 136

Sampling,Quantizing,and Encoding, 137

Practical PCM Circuits. 140

Bandwidth of PCM. 141

Effecis of Noise 143

Example3-1 Design of a PCM Systm. 145

Nonuniform Quantizing:μ-Law and A-Law Companding. 146

3-4 Digital Signaling 148

Vector Representation. 150

Example3-2 Vector Representation of a Binary Signal. 151

Bandwidth Estimation. 151

Binary Signaling. 152

Example3-3 Binary Signaling. 153

Multilevel Signaling 154

Example3-4 L=4Multilevel Signal. 155

3-5 Line Codes and Spectra 157

Binary Line Coding. 157

Power Spectra for Binary Line Codes. 159

Differential Coding. 166

Eye Patterns. 167

Regenerative Repeaters. 168

Bit Synckronization. 170

Power Spectra for Multilevel Signals. 173

Spectral Efficiency. 175

3-6 Intersymbol Interference 176

Nyquist s First Method(Zero ISI). 179

Raised Cosine-Rolloff Filtering. 180

Example3-1 (contiruesd). 182

Nyquist s Second and Third Methods for Courol of ISI, 184

3-7 Differential Pulse Code Modulation 185

3-8 Delta Modulation 189

Granular Noise and Slope Overload Noise. 190

Example3-5 Design of a DM System. 191

Adaptive Delta Modulation and Continuously Variable Slope Delta Modulation. 193

Speech Coding. 194

3-9 Time-Division Multiplexing 196

Frame Synchronization. 196

Synchronous and Asynchronous Lines. 200

Example3-6 Design of a Time-Division Multiplexer. 201

TDM Hierarchy. 203

The TI PCM System. 205

3-10 Pulse Time Modulation:Pulse Width Modulation and Pulse Poisition Modulation 209

3-11 Summary 210

3-12 Study-Aid Examples 214

Problems 217

4 BANDPASS SIGNALING PRINCIPLES AND CIRCUITS 226

4-1 Complex Envelope Representation of Bandpass Waveforms 226

Definitions:Baseband,Bandpass,and Modulation. 227

Complex Eavelope Representafion. 228

4-2 Representation of Modulated Signals 229

4-3 Spectrum of Bandpass Signals 230

4-4 Evaluation of Power 233

Example4-1 Amplitude-Modulated Signal. 234

4-5 Bandpass Filtering and Linear Distortion 236

Equivatem Low-Pass Filter. 236

Linear Distortion. 238

4-6 Bandpass Sampling Theorem 240

4-7 Received Signal Plus Noise 241

4-8 Classification of Filters and Amplifiers 242

Filters. 242

Amplifiers. 246

4-9 Nonlinear Distortion 247

4-10 Limiters 252

4-11 Mixers.Up Converters,and Down Converters 253

4-12 Frequency Multipliers 259

4-13 Detector Circuits 261

Envelope Detector. 261

Product Detector. 262

Frequency Modulation Detector. 264

4-14 Phase-Locked Loops and Frequency Synthesizers 269

4-15 Direct Digital Synthesis 276

4-16 Transmitters and Receivers 277

Generalized Transmitters. 277

Generalized Receiver,The Superheterodyne Receiver. 279

Exampl4-2 AM Broadcust Superheterodyne Receiver. 281

4-17 Summary 283

4-18 Study-Aid Examples 283

Problems 288

5 AM,FM,AND DIGITAL MODULATED SYSTEMS 295

5-1 Amplitude Modulation 296

Example5-1 Power of an AM Sigual. 299

5-2 AM Broadcast Technical Standards 301

5-3 Double-Sideband Suppressed Carrier 302

5-4 Custas Loop and Squaring Loop 303

5-5 Asymmetric Sideband Signals 304

Single Sideband. 304

Vestigial Sideband. 308

5-6 Phase Modulation and Frequency Modulation 311

Representation of PM and FM signals 311

Spectra of Angle-Modulated Signals. 315

Example5-2 Spectrum of a PM or FM Signal with Sinusoidal Modutation. 316

Narrowband Angle Modulation. 321

Wideband Frequeney Modulation. 322

Example5-3 Spectrum for WBFM with Triangular Modulation. 323

Preemphasis and Deemphasis in Angte-Modulated Systems. 325

5-7 Frequency-Division Multiplexing and FM Stereo 326

5-8 FM and Noise Reduction Standards 329

FM Broudcust Technical Standards. 329

Dolby and DBX Noise Reduction Systems. 329

5-9 Binary Modulated Bandpass Signaling 332

On-Off Keying (OOK), 332

Binary-Phase Shift Keying(BPSK). 336

Differential Phase-Shift Keying (DPSK). 337

Frequency-Shift Keying(FSK). 338

Example5-4 Spectrum of the Bell-Type 103 FSK Modem. 339

5-10 Multilevel Modulated Bandpass Signaling 345

Qundrature Phase-Shift (QPSK)Keying andM-ary Phase-Shift Keying(MPSK). 345

Quadrature Amplitude Modulation(QAM), 346

Power Spectral Density for Mpsk and QAM. 349

5-11 Minimum-Shift Keying(MSK) 352

5-12 Spread Spectrum Systems 357

Direct Sequence. 358

Frequency Hopping. 364

5-13 Summary 366

5-14 Study-Aid Examples 366

Problems 369

6 RANDOM PROCESSES AND SPECTRAL ANALYSIS 381

6-1 Some Basic Definitions 382

Random Pmcesses, 382

Stationarity and Ergodicity. 383

Example6-1 First-Order Stationarity. 383

Example6-2 Ergodic Random Process. 385

Correlation Functions and Wide-Sense Stationarity. 386

Complex Random Processes. 390

6-2 Power Spectral Density 391

Definition. 391

Wiener-Khintchine Theorem 392

Properties of the PSD, 395

Example6-3 Evaluction of the PSD for a Ploar Baseband Signal. 395

Generul Formula for the PSD of Digital Signals 399

White Noise Processes. 402

Measurement of PSD. 403

6-3 De and Rms Values for Ergodic RandomProcesses 404

6-4 Linear Systems 406

Input-Output Relationships. 406

Example6-4 Output Autocorrelation and PSD for an RC Low-Pass Filter, 409

Example6-5 Signal-to-Noise Ratio at the Outpul of an RC Low-Pass Filter. 410

6-5 Bandwidth Measures 411

Equivatent Bandwidth. 411

Rms Bandwidth. 411

Example6-6 Equivalent Bandwidth and Rms Bandwidth for od RC LPF. 413

6-6 The Gaussian Random Process 413

Propenies of Gamssion Processes. 415

Example6-7 White Gaussian Noise Prcess. 417

6-7 Bandpass Processes 418

Bandpass Represemations. 418

Propenies of WSS Bandpass Processes. 421

Example6-8 Spectra for the Quadrature Compenents of White Bandpuss Noise. 424

Example6-9 PSD for a BPSK Signal, 424

Proofs of Some Properties. 425

Example 6-10 PDF for the Envelope and Phase Functions of a Gaussion Bandpass Process. 428

6-8 Matched Filters 430

General Results. 430

Results for White Noise. 433

Example6-11 Integrate-and -Dump(Matched)Filter, 434

Correlution Processing. 437

Example6-12 Matched Filter for Detection of a BPSK Signal. 437

Transversal Matched Filter. 438

6-9 Summary 441

6-10 Appendix:Proof of Schwars s Inequality 443

6-11 Study-Aid Examples 446

Problems 448

7 PERFORMANCE OF COMMUNICATION SYSTEMS CORRUPTED BY NOISE 458

7-1 Error Probabilities for Binay Signaling 459

General Results. 459

Results for Gaussion Noise. 461

Resulos for White Gaussion Noise and Matched-Filter Reception. 463

Results for Colored Gaussian Noise and Matched-Filter Reception, 464

7-2 Performance of Baseband Binary Systems 465

Unipotar Signaling. 465

Polar Signaling. 467

Bipolar Signaling. 468

7-3 Noncoherent Detection of Bandpass Binary Signals 470

On-Off Keying. 470

Binary-Phase-Shift Keying. 472

Prequener-Shift Keying. 473

7-4 Noncoherent Detection of Bandpass Binary Signals 476

On-Off Keyign. 477

Frequeney Shift Keying. 480

Differential Phase-Shift Keying. 482

7-5 Quadrature Phase-Shift Keying and Minimum-Shift Keying 484

7-6 Comparison of Digital Signaling Systems 487

Bit Error Rate and Bandwidth. 487

Synchrunization. 489

7-7 Output Signal-to-Noise Ratio for PCM Systems 490

7-8 Output Signal-to-Noise Ratios for Analog Systems 495

Comparison with Baseband Systems/ 496

AM Systems with Product Detection. 497

AM Systems with Envelope Detection. 498

DSB-SC Systems. 499

SSB Systems. 500

PM Systems. 501

FM Systems. 505

FM Systems with Threshold Extension 508

FM Systems with Deemphasis. 509

7-9 Comparison of Analog Signaling Systems 511

Ideal System Performance. 514

7-10 Summary 515

7-11 Study-Aid Examples 515

Problems 524

8 CASE STUDIES OF COMMUNICATION SYSTEMS 533

8-1 Telecommunication Systems 534

Time-Division Multiplexing. 534

Frequency-Division Multiptexing. 534

8-2 Telephone Systems 536

Historical Basis. 536

Modem Tlephone Systems and Remote Tenninals . 536

8-3 Integrated Service Digital Network 543

8-4 Capacities of Public Switched Telepone Networks 547

8-5 Satellite Communication Systems 547

Digital and Analog Television Transmission 551

Data and Telephone Signal Multiple Access. 553

Example8-1 Fixed Assigned Multiple-Access Mode Using an FDMA Format, 554

Example8-2 SPADE System, 555

Personal Communications via Satellite. 559

8-6 Link Budget Analysis 560

Signal Power Received. 561

Thermal Noise Soercs. 563

Characterization of Noise Sources, 564

Nois Characterization of Linear Devices, 565

Example8-3 T and F for a Transmission Line. 569

Noise Characterization of Cascaded Linear Dtyices, 570

Link Budget Evatuation, 572

Eb/Na Link Budget for Digital Systems. 574

Example8-4 Link Badget Evaluation for a Television Receive Only Terminat for Satellite Signals. 575

8-7 Fiber Optic Systems 580

Example8-5 Link Budget for a Fiber Optic System. 581

8-8 Cellular Telephone Systems 582

8-9 Television 589

Black-and-White Television. 589

MTS Stereo Sound. 596

Color Television. 596

Standards for TV and CATV Systems. 601

8-10 Summary 609

8-11 Study-Aid Examples 609

Problems 614

APPENDIX A MATHEMATICAL TECHNIQUES,IDENTTTIES, AND TABLES 620

A-1 Trigonomerty 620

Definitions, 620

Trigonometrie Identities. 620

A-2 Differential Calculus 621

Definifion, 621

Differentiation Rules, 621

Derivative Table, 622

A-3 Indeterminate Forms 623

A-4 Integral Calculus 623

Definition, 623

Integration Techniques, 623

A-5 Integral Tables 623

indefinite Integrals . 623

Definite Integrals, 626

A-6 Series Expansions 627

Finite Series, 627

Infinite Series, 628

A-7 Hilbert Transform Pairs 629

A-8 The Dirac Delta Function 629

Properties of Dirac Delta Function, 630

A-9 Tabulation of Sa(x)=(sinx.)/x 631

A-10 Tabulation of Q(z) 632

APPENDIX B PROBABILITY AND RANDOM VARIABLES 634

B-1 Introduction 634

B-2 Sets 635

B-3 Probability and Relative Frequency 636

Simple Probability, 636

Join Probabiliry. 637

ExampleB-1 Evaluation of Probubilities, 637

ExampleB-1 (Continued), 638

Condinonat Probabilities, 638

ExampleB-1 (Continued), 638

B-4 Random Variables 639

ExampleB-2 Random Variable, 639

B-5 Cumulative Distribution Functions and Probability Density Functions 639

ExamlpeB-2 (Continued), 641

Properties of CDFs and PDFs, 642

Discrete and Continuous Distributions, 642

ExampleB-3 A Contimuous Distribution 642

ExampleB-3 (Continued), 644

B-6 Ensemble Average and Moments 646

Ensemble Average, 646

ExampleB-4 Evaluation of an Average, 647

Moments, 647

B-7 Examples of Important Distributions 649

Binontiol Distribution, 649

Poisson Distribution, 652

Uniform Distribution, 652

Gaussion Distribution, 653

Sinusoidal Distribution, 657

B-8 Functional Transformations of Random Variables 658

ExampleB-5 Sinusoidal Distribution, 659

ExampleB-6 PDF for the Output of a Diode Characteristic, 660

B-9 Multivariate Statistics 663

Multivariate CDFx and PDFx, 663

Bivnriate Statistics, 665

Camssian Bivariate Distribution, 666

Multivariate Functional Transformation, 666

ExampleB-7 PDF for the Sun of Two Random Variables, 667

Central Limil Theorem, 669

ExampleB-8 PDF for the Sun of Three independent Uniformtly Disiributed Random Variables, 669

Problems 670

APPENDIX C STANDARDS AND TERMINOLOGY FOR COMPUTER COMMUNICATIONS 677

C-1 Codes 677

Baudot, 677

ASCII, 678

C-2 DTE/DCE and Ethernet Interface Standards 678

Current Loop, 680

Rs-232C,RS-422A,RS-449,and RS-530 interfaces, 680

Centronics Parallel Interface, 681

IEEE-488Interface, 681

Ethernet(IEEE802.3)Interface, 684

C-3 The ISO OSI Network Model 686

C-4 Data Link Control Protocols 690

BISYNC. 690

SDLC. 690

HDLC. 690

CCITTX.25 Protocol, 691

Asynchronous Transfer Mode (ATM), 692

C-5 Modem Standards 693

C-6 Brief Computer Communications Glossary 698

REFERENCES 703

ANSWERS TO SELECTED PROBLEMS 714

INDEX 720