《数字与模拟通信系统 第5版》

1INTRODUCTION1

1-1 Historical Perspective2

1-2 Digital and Analog Sources and Systems2

1-3 Deterministic and Random Waveforms6

1-4 Organization of This Book6

1-5 Use of a personal Computer and MATLAB7

1-6 Block Diagram of a Communication System8

1-7 Frequency Allocations9

1-8 Propagation of Electromagnetic Waves10

1-9Information Measure16

Example1-1 Evaluation of information and Entropy,17

1-10 Channel Capacity and ldeal Communication Systems18

1-11Coding19

Block Codes21

Convolutional Codes.21

Code interleaving.23

Code performance.24

Trellis-Coded Modulation.27

1-12 Preview30

1-13Study-aid Examples30

Problems31

2SIGNALS AND SPECTRA33

2-1Properties of Signals and Noise33

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

2-2Fourier Transform and Spectra43

Definition.43

Example2-2Spectrum of an Exponentiat Pulse.45

Propertise of Fourier Transforms.46

Parseval s Theorem and Energy Spectral Density.47

Example2-3Spectrum of a Damped Sinusoid.49

Dirac Data Function and Unit Step Function,50

Example2-4Spectrum of a Sinusold.52

Rectangular and Triangular-Pulses.54

Example2-5Spectrum of a Rectangular Pulse.54

Example2-6 Spectrum of a Triangular Pulse.57

Convolution.58

Example2-7Convolution 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

2-3Power Spectral Density and Autocorrelation Function62

Power Spectral Density.62

Autocotrelation Function.63

Example2-10PSD of a Sinusoid.63

2-4Orthogonal Series Representation of Signals and Noise65

Orthogonal Functions.65

Example2-11Orthogonal Complex Exponential Functions.66

Orthogonal Series.66

2-5Fourier Series68

Complex Fourier Series.68

Quadrature Fourier Series.70

Polar Fourier Series.71

Line Spectra for Periodic Waveforms.73

Example2-12Fourier Coefficienis for a Rectangular Wave,75

Power Spectral Density for Periodic Waveforms.76

Example2-13PSD for a Square Wave.77

2-6Review of Linear Systems78

linecr Time-Invariont Systems.78

Impulse Response.79

Tnmifer Fwtction.79

Example2-14RC Low-Pass Filter.81

Distortionless Transmission83

Example2-15Distortion Caused by a Filter.83

2-7Bandlimited Signals and Noise84

Bandlimited Waveforms.86

Sampling Theorem.86

Impulse Sampling.89

Dimensionolity Theorem.92

2-8Discrete Fourier Transform93

Using the DFT to Compute the Contisuous Fourier Transform.94

Example2-16DFT for a Rectangular pulse.97

Using the DFT to Compute the Fourier Series.100

Example2-17Use the DFT to Compute the Spectrum of a Sinusoid100

2-9Bandwidth of Signals101

Example2-18 Bandwidths for a BPSK Signal.105

2-10 Summary109

2-11Study-Aid Examples110

Problems113

3BASEBAND PULSE AND DIGIIAL SIGNALING127

3-1 Introduction127

3-2Pulse Amplitude Modulation128

Natural Sampling (Gating).129

Instantaneous Sampling(Flat-Top PAM).133

3-3Pulse Code Modulation136

Sampling,Quantizing,and Encoding,137

Practical PCM Circuits.140

Bandwidth of PCM.141

Effecis ofNoise143

Example3-1 Design of a PCM Systm.145

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

3-4Digital Signaling148

Vector Representation.150

Example3-2Vector Representation of a Binary Signal.151

Bandwidth Estimation.151

Binary Signaling.152

Example3-3Binary Signaling.153

Multilevel Signaling154

Example3-4L=4Multilevel Signal.155

3-5Line Codes and Spectra157

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

3-6Intersymbol Interference176

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 Modulation185

3-8Delta Modulation189

Granular Noise and Slope Overload Noise.190

Example3-5Design of a DM System.191

Adaptive Delta Modulation and Continuously Variable Slope Delta Modulation.193

Speech Coding.194

3-9Time-Division Multiplexing196

Frame Synchronization.196

Synchronous and Asynchronous Lines.200

Example3-6Design 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 Modulation209

3-11 Summary210

3-12Study-Aid Examples214

Problems217

4BANDPASS SIGNALING PRINCIPLES AND CIRCUITS226

4-1Complex Envelope Representation of Bandpass Waveforms226

Definitions:Baseband,Bandpass,and Modulation.227

Complex Eavelope Representafion.228

4-2 Representation of Modulated Signals229

4-3 Spectrum of Bandpass Signals230

4-4Evaluation of Power233

Example4-1 Amplitude-Modulated Signal.234

4-5Bandpass Filtering and Linear Distortion236

Equivatem Low-Pass Filter.236

Linear Distortion.238

4-6 Bandpass Sampling Theorem240

4-7 Received Signal Plus Noise241

4-8Classification of Filters and Amplifiers242

Filters.242

Amplifiers.246

4-9 Nonlinear Distortion247

4-10 Limiters252

4-11 Mixers.Up Converters,and Down Converters253

4-12 Frequency Multipliers259

4-13Detector Circuits261

Envelope Detector.261

Product Detector.262

Frequency Modulation Detector.264

4-14 Phase-Locked Loops and Frequency Synthesizers269

4-15 Direct Digital Synthesis276

4-16Transmitters and Receivers277

Generalized Transmitters.277

Generalized Receiver,The Superheterodyne Receiver.279

Exampl4-2AM Broadcust Superheterodyne Receiver.281

4-17 Summary283

4-18Study-Aid Examples283

Problems288

5AM,FM,AND DIGITAL MODULATED SYSTEMS295

5-1Amplitude Modulation296

Example5-1 Power of an AM Sigual.299

5-2 AM Broadcast Technical Standards301

5-3 Double-Sideband Suppressed Carrier302

5-4 Custas Loop and Squaring Loop303

5-5Asymmetric Sideband Signals304

Single Sideband.304

Vestigial Sideband.308

5-6Phase Modulation and Frequency Modulation311

Representation of PM and FM signals311

Spectra of Angle-Modulated Signals.315

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

Narrowband Angle Modulation.321

Wideband Frequeney Modulation.322

Example5-3Spectrum for WBFM with Triangular Modulation.323

Preemphasis and Deemphasis in Angte-Modulated Systems.325

5-7 Frequency-Division Multiplexing and FM Stereo326

5-8FM and Noise Reduction Standards329

FM Broudcust Technical Standards.329

Dolby and DBX Noise Reduction Systems.329

5-9Binary Modulated Bandpass Signaling332

On-Off Keying (OOK),332

Binary-Phase Shift Keying(BPSK).336

Differential Phase-Shift Keying (DPSK).337

Frequency-Shift Keying(FSK).338

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

5-10Multilevel Modulated Bandpass Signaling345

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

5-12Spread Spectrum Systems357

Direct Sequence.358

Frequency Hopping.364

5-13 Summary366

5-14Study-Aid Examples366

Problems369

6RANDOM PROCESSES AND SPECTRAL ANALYSIS381

6-1Some Basic Definitions382

Random Pmcesses,382

Stationarity and Ergodicity.383

Example6-1First-Order Stationarity.383

Example6-2 Ergodic Random Process.385

Correlation Functions and Wide-Sense Stationarity.386

Complex Random Processes.390

6-2Power Spectral Density391

Definition.391

Wiener-Khintchine Theorem392

Properties of the PSD,395

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

Generul Formula for the PSD of Digital Signals399

White Noise Processes.402

Measurement of PSD.403

6-3 De and Rms Values for Ergodic RandomProcesses404

6-4Linear Systems406

Input-Output Relationships.406

Example6-4Output 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

6-5Bandwidth Measures411

Equivatent Bandwidth.411

Rms Bandwidth.411

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

6-6The Gaussian Random Process413

Propenies of Gamssion Processes.415

Example6-7White Gaussian Noise Prcess.417

6-7Bandpass Processes418

Bandpass Represemations.418

Propenies of WSS Bandpass Processes.421

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

Example6-9 PSD for a BPSK Signal,424

Proofs of Some Properties.425

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

6-8Matched Filters430

General Results.430

Results for White Noise.433

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

Correlution Processing.437

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

Transversal Matched Filter.438

6-9 Summary441

6-10 Appendix:Proof of Schwars s Inequality443

6-11Study-Aid Examples446

Problems448

7PERFORMANCE OF COMMUNICATION SYSTEMS CORRUPTED BY NOISE458

7-1Error Probabilities for Binay Signaling459

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

7-2Performance of Baseband Binary Systems465

Unipotar Signaling.465

Polar Signaling.467

Bipolar Signaling.468

7-3Noncoherent Detection of Bandpass Binary Signals470

On-Off Keying.470

Binary-Phase-Shift Keying.472

Prequener-Shift Keying.473

7-4Noncoherent Detection of Bandpass Binary Signals476

On-Off Keyign.477

Frequeney Shift Keying.480

Differential Phase-Shift Keying.482

7-5 Quadrature Phase-Shift Keying and Minimum-Shift Keying484

7-6Comparison of Digital Signaling Systems487

Bit Error Rate and Bandwidth.487

Synchrunization.489

7-7 Output Signal-to-Noise Ratio for PCM Systems490

7-8Output Signal-to-Noise Ratios for Analog Systems495

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 Extension508

FM Systems with Deemphasis.509

7-9Comparison of Analog Signaling Systems511

Ideal System Performance.514

7-10 Summary515

7-11Study-Aid Examples515

Problems524

8CASE STUDIES OF COMMUNICATION SYSTEMS533

8-1Telecommunication Systems534

Time-Division Multiplexing.534

Frequency-Division Multiptexing.534

8-2Telephone Systems536

Historical Basis.536

Modem Tlephone Systems and Remote Tenninals .536

8-3 Integrated Service Digital Network543

8-4 Capacities of Public Switched Telepone Networks547

8-5Satellite Communication Systems547

Digital and Analog Television Transmission551

Data and Telephone Signal Multiple Access.553

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

Example8-2 SPADE System,555

Personal Communications via Satellite.559

8-6Link Budget Analysis560

Signal Power Received.561

Thermal Noise Soercs.563

Characterization of Noise Sources,564

Nois Characterization of Linear Devices,565

Example8-3T 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

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

8-7Fiber Optic Systems580

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

8-8 Cellular Telephone Systems582

8-9Television589

Black-and-White Television.589

MTS Stereo Sound.596

Color Television.596

Standards for TV and CATV Systems.601

8-10 Summary609

8-11Study-Aid Examples609

Problems614

APPENDIX AMATHEMATICAL TECHNIQUES,IDENTTTIES, AND TABLES620

A-1Trigonomerty620

Definitions,620

Trigonometrie Identities.620

A-2Differential Calculus621

Definifion,621

Differentiation Rules,621

Derivative Table,622

A-3 Indeterminate Forms623

A-4Integral Calculus623

Definition,623

Integration Techniques,623

A-5Integral Tables623

indefinite Integrals .623

Definite Integrals,626

A-6Series Expansions627

Finite Series,627

Infinite Series,628

A-7 Hilbert Transform Pairs629

A-8The Dirac Delta Function629

Properties of Dirac Delta Function,630

A-9 Tabulation of Sa(x)=(sinx.)/x631

A-10 Tabulation of Q(z)632

APPENDIX BPROBABILITY AND RANDOM VARIABLES634

B-1 Introduction634

B-2 Sets635

B-3Probability and Relative Frequency636

Simple Probability,636

Join Probabiliry.637

ExampleB-1Evaluation of Probubilities,637

ExampleB-1 (Continued),638

Condinonat Probabilities,638

ExampleB-1(Continued),638

B-4Random Variables639

ExampleB-2 Random Variable,639

B-5Cumulative Distribution Functions and Probability Density Functions639

ExamlpeB-2 (Continued),641

Properties of CDFs and PDFs,642

Discrete and Continuous Distributions,642

ExampleB-3A Contimuous Distribution642

ExampleB-3 (Continued),644

B-6Ensemble Average and Moments646

Ensemble Average,646

ExampleB-4Evaluation of an Average,647

Moments,647

B-7Examples of Important Distributions649

Binontiol Distribution,649

Poisson Distribution,652

Uniform Distribution,652

Gaussion Distribution,653

Sinusoidal Distribution,657

B-8Functional Transformations of Random Variables658

ExampleB-5 Sinusoidal Distribution,659

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

B-9Multivariate Statistics663

Multivariate CDFx and PDFx,663

Bivnriate Statistics,665

Camssian Bivariate Distribution,666

Multivariate Functional Transformation,666

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

Central Limil Theorem,669

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

Problems670

APPENDIX CSTANDARDS AND TERMINOLOGY FOR COMPUTER COMMUNICATIONS677

C-1Codes677

Baudot,677

ASCII,678

C-2DTE/DCE and Ethernet Interface Standards678

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 Model686

C-4Data Link Control Protocols690

BISYNC.690

SDLC.690

HDLC.690

CCITTX.25 Protocol,691

Asynchronous Transfer Mode (ATM),692

C-5 Modem Standards693

C-6 Brief Computer Communications Glossary698

REFERENCES703

ANSWERS TO SELECTED PROBLEMS714

INDEX720