Chapter 1 Introduction 1
1.1 Elements and Limitations of Communications Systems 2
Information，Messages，and Signals 2
Elements of a Communication System 3
Fundamental Limitations 5
1.2 Modulation and Coding 6
Modulation Methods 6
Modulation Benefits and Applications 7
Coding Methods and Benefits 10
1.3 Historical Perspective and Societal Impact 11
Historical Perspective 12
Societal Impact 14
1.4 Prospectus 15
Chapter 2 Signals and Spectra 17
2.1 Line Spectra and Fourier Series 19
Phasors and Line Spectra 19
Periodic Signals and Average Power 23
Fourier Series 25
Convergence Conditions and Gibbs Phenomenon 29
Parseval’s Power Theorem 31
Fourier Transforms 33
2.2 Fourier Transforms and Continuous Spectra(2.1) 33
Symmetric and Causal Signals 37
Rayleigh’s Energy Theorem 40
Duality Theorem 42
Transform Calculations 44
2.3 Time and Frequency Relations(2.2) 44
Superposition 45
Time Delay and Scale Change 45
Frequency Translation and Modulation 48
Differentiation and Integration 50
2.4 Convolution(2.3) 52
Convolution Integral 53
Convolution Theorems 55
2.5 Impulses and Transforms in the Limit (2.4) 58
Properties of the Unit Impulse 58
Impulses in Frequency 61
Step and Signum Functions 64
Impulses in Time 66
Chapter 3 Signal Transmission and Filtering 75
3.1 Response of LTI Systems(2.4) 76
Impulse Response and the Superposition Integral 77
Transfer Functions and Frequency Response 80
Block-Diagram Analysis 86
3.2 Signal Distortion in Transmission(3.1) 89
Distortionless Transmission 89
Linear Distortion 91
Equalization 94
Nonlinear Distortion and Companding 97
3.3 Transmission Loss and Decibels(3.2) 99
Power Gain 99
Transmission Loss and Repeaters 101
Fiber Optics 102
Radio Transmission 106
3.4 Filters and Filtering(3.3) 109
Ideal Filters 109
Bandlimiting and Timelimiting 111
Real Filters 112
Pulse Response and Risetime 116
3.5 Quadrature Filters and Hilbert Transforms(3.4) 120
3.6 Correlation and Spectral Density(3.3) 124
Correlation of Power Signals 124
Correlation of Energy Signals 127
Spectral Density Functions 130
Chapter 4 Linear CW Modulation 141
4.1 Bandpass Signals and Systems(3.4) 142
Analog Message Conventions 143
Bandpass Signals 144
Bandpass Transmission 147
4.2 Double-Sideband Amplitude Modulation(4.1) 152
AM Signals and Spectra 152
DSB Signals and Spectra 154
Tone Modulation and Phasor Analysis 157
Product Modulators 158
4.3 Modulators and Transmitters(4.2) 158
Square-Law and Balanced Modulators 160
Switching Modulators 162
4.4 Suppressed-Sideband Amplitude Modulation(3.5，4.3) 164
SSB Signals and Spectra 164
SSB Generation 167
VSB Signals and Spectra 170
4.5 Frequency Conversion and Demodulation(4.4) 172
Frequency Conversion 172
Synchronous Detection 173
Envelope Detection 176
Chapter 5 Exponential CW Modulation 183
PM and FM signals 184
5.1 Phase and Frequency Modulation(4.3) 184
Narrowband PM and FM 188
Tone Modulation 189
Multitone and Periodic Modulation 196
5.2 Transmission Bandwidth and Distortion(5.1) 199
Transmission Bandwidth Estimates 199
Linear Distortion 202
Nonlinear Distortion and Limiters 205
Direct FM and VCOs 208
5.3 Generation and Detection of FM and PM(4.5，5.2) 208
Phase Modulators and Indirect FM 209
Triangular-Wave FM 212
Frequency Detection 214
5.4 Interference(5.3) 219
Interfering Sinusoids 219
Deemphasis and Preemphasis Filtering 221
FM Capture Effect 224
Chapter 6 Sampling and Pulse Modulation 231
Chopper Sampling 232
6.1 Sampling Theory and Practice(4.2) 232
Ideal Sampling and Reconstruction 237
Practical Sampling and Aliasing 240
6.2 Pulse-Amplitude Modulation(6.1) 245
Flat-Top Sampling and PAM 245
6.3 Pulse-Time Modulation(6.2) 248
Pulse-Duration and Pulse-Position Modulation 248
PPM Spectral Analysis 251
Chapter 7 Analog Communication Systems 257
Superheterodyne Receivers 258
7.1 Receivers for CW Modulation(5.3) 258
Direct Conversion Receivers 262
Special-Purpose Receivers 262
Receiver Specifications 264
Scanning Spectrum Analyzers 265
7.2 Multiplexing Systems(5.3，6.1) 266
Frequency-Division Multiplexing 266
Quadrature-Carrier Multiplexing 271
Time-Division Multiplexing 272
Cross Talk and Guard Times 276
Comparison of TDM and FDM 277
PLL Operation and Lock-In 278
7.3 Phase-Lock Loops(7.1) 278
Synchronous Detection and Frequency Synthesizers 281
Linearized PLL Models and FM Detection 285
7.4 Television Systems(7.1) 286
Video Signals，Resolution，and Bandwidth 287
Monochrome Transmitters and Receivers 292
Color Television 294
HDTV 299
Chapter 8 Probability and Random Variables 311
Probabilities and Events 312
8.1 Probability and Sample Space 312
Sample Space and Probability Theory 313
Conditional Probability and Statistical Independence 317
8.2 Random Variables and Probability Functions(8.1) 320
Discrete Random Variables and CDFs 320
Continuous Random Variables and PDFs 323
Transformations of Random Variables 327
Joint and Conditional PDFs 329
8.3 Statistical Averages(2.3，8.2) 330
Means，Moments，and Expectation 331
Standard Deviation and Chebyshev’s Inequality 332
Multivariate Expectations 334
Characteristic Functions 336
8.4 Probability Models(8.3) 337
Binomial Distribution 337
Poisson Distribution 338
Gaussian PDF 339
Rayleigh PDF 342
Bivariate Gaussian Distribution 344
Chapter 9 Random Signals and Noise 351
9.1 Random Processes(3.6，8.4) 352
Ensemble Averages and Correlation Functions 353
Ergodic and Stationary Processes 357
Gaussian Processes 362
9.2 Random Signals(9.1) 362
Power Spectrum 362
Superposition and Modulation 367
Filtered Random Signals 368
9.3 Noise(9.2) 371
Thermal Noise and Available Power 372
White Noise and Filtered Noise 375
Noise Equivalent Bandwidth 378
System Measurements Using White Noise 380
9.4 Baseband Signal Transmission with Noise(9.3) 381
Additive Noise and Signal-to-Noise Ratios 382
Analog Signal Transmission 383
9.5 Baseband Pulse Transmission with Noise(9.4) 386
Pulse Measurements in Noise 386
Pulse Detection and Matched Filters 388
Chapter 10 Noise in Analog Modulation Systems 397
10.1 Bandpass Noise(4.4，9.2) 398
System Models 399
Quadrature Components 401
Envelope and Phase 403
Correlation Functions 404
10.2 Linear CW Modulation with Noise(10.2) 406
Synchronous Detection 407
Envelope Detection and Threshold Effect 409
10.3 Exponential CW Modulation with Noise(5.3，10.2) 412
Postdetection Noise 412
Destination S/N 416
FM Threshold Effect 418
Threshold Extension by FM Feedback 421
10.4 Comparison of CW Modulation Systems(9.4，10.3) 422
10.5 Phase-Lock Loop Noise Performance(7.3，10.1) 425
10.6 Analog Pulse Modulation with Noise(6.3，9.5) 426
Signal-to-Noise Ratios 426
False-Pulse Threshold Effect 429
Chapter 11 Baseband Digital Transmission 435
11.1 Digital Signals and Systems(9.1) 437
Digital PAM Signals 437
Transmission Limitations 440
Power Spectra of Digital PAM 443
Spectral Shaping by Precoding 446
Binary Error Probabilities 448
11.2 Noise and Errors(9.4，11.1) 448
Regenerative Repeaters 453
Matched Filtering 454
M-ary Error Probabilities 457
11.3 Bandlimited Digital PAM Systems(11.2) 461
Nyquist Pulse Shaping 461
Optimum Terminal Filters 464
Equalization 467
Correlative Coding 470
11.4 Synchronization Techniques(11.2) 476
Bit Synchronization 477
Scramblers and PN Sequence Generators 479
Frame Synchronization 484
Chapter 12 Digitization Techniques for Analog Messages and Networks 493
12.1 Pulse-Code Modulation(6.2，11.1) 495
PCM Generation and Reconstruction 495
Quantization Noise 499
Nonuniform Quantizing and Companding 501
12.2 PCM with Noise(11.2，12.1) 504
Decoding Noise 505
Error Threshold 507
PCM Versus Analog Modulation 508
12.3 Delta Modulation and Predictive Coding(12.2) 510
Delta Modulation 510
Delta-Sigma Modulation 516
Adaptive Delta Modulation 516
Differential PCM 518
LPC Speech Synthesis 520
12.4 Digital Audio Recording(12.3) 522
CD Recording 523
CD Playback 525
12.5 Digital Multiplexing(12.1) 526
Multiplexers and Hierarchies 527
Digital Subscriber Lines 530
Integrated Services Digital Network 532
Synchronous Optical Network 533
Data Multiplexers 535
12.6 Computer Networks(12.5) 537
Open Systems Interconnection 538
Transmission Control Protocol/Internet Protocol 539
Chapter 13 Channel Coding and Encryption 547
13.1 Error Detection and Correction(11.2) 549
Repetition and Parity-Check Codes 549
Interleaving 550
Code Vectors and Hamming Distance 552
FEC Systems 553
ARQ Systems 556
13.2 Linear Block Codes(13.1) 560
Matrix Representation of Block Codes 560
Syndrome Decoding 564
Cyclic Codes 567
M-ary Codes 573
13.3 Convolutional Codes(13.2) 574
Convolutional Encoding 574
Free Distance and Coding Gain 580
Decoding Methods 585
Turbo Codes 592
13.4 Data Encryption(13.1) 594
Data Encryption Standard 598
Rivest-Shamir-Adleman System 602
Chapter 14 Bandpass Digital Transmission 611
14.1 Digital CW Modulation(4.5，5.1，11.1) 612
Spectral Analysis of Bandpass Digital Signals 613
Amplitude Modulation Methods 614
Phase Modulation Methods 617
Frequency Modulation Methods 619
Minimum-Shift Keying 622
14.2 Coherent Binary Systems(11.2，14.1) 626
Optimum Binary Detection 626
Coherent OOK，BPSK，and FSK 631
Timing and Synchronization 633
14.3 Noncoherent Binary Systems(14.2) 634
Envelope of a Sinusoid Plus Bandpass Noise 634
Noncoherent OOK 636
Noncoherent FSK 638
Differentially Coherent PSK 640
14.4 Quadrature-Carrier and M-ary Systems(14.2) 644
Quadrature-Carrier Systems 644
M-ary PSK Systems 646
M-ary QAM Systems 650
Comparison of Digital Modulation Systems 653
14.5 Trellis-Coded Modulation 655
TCM Basics 656
Hard Versus Soft Decisions 664
Modems 665
Chapter 15 Spread Spectrum Systems 671
15.1 Direct Sequence Spread Spectrum(14.2) 672
DSS Signals 673
DSS Performance in the Presence of Interference 676
Multiple Access 678
15.2 Frequency Hop Spread Spectrum(15.1) 679
FH-SS Signals 680
FH-SS Performance in the Presence of Interference 682
15.3 Coding(15.1) 684
15.4 Synchronization(7.3) 689
Acquisition 689
Tracking 691
15.5 Wireless Telephone Systems(15.1) 692
Cellular Telephone Systems 693
Personal Communication Systems 693
Chapter 16 Information and Detection Theory 696
16.1 Information Measure and Source Coding(12.1) 699
Information Measure 700
Entropy and Information Rate 701
Coding for a Discrete Memoryless Channel 705
Predictive Coding for Sources with Memory 709
Mutual Information 713
16.2 Information Transmission on Discrete Channels(16.1) 713
Discrete Channel Capacity 717
Coding for the Binary Symmetric Channel 719
16.3 Continuous Channels and System Comparisons(16.2) 722
Continuous Information 722
Continuous Channel Capacity 725
Ideal Communication Systems 727
System Comparisons 731
16.4 Signal Space 735
Signals as Vectors 735
The Gram-Schmidt Procedure 738
16.5 Optimum Digital Detection(16.3，16.4) 740
Optimum Detection and MAP Receivers 741
Error Probabilities 747
Signal Selection and Orthogonal Signaling 751
Appendix：Circuit and System Noise(9.4) 760
Circuit and Device Noise 761
Amplifier Noise 768
System Noise Calculations 773
Cable Repeater Systems 777
Tables 780
T.1 Fourier Transforms 780
T.2 Fourier Series 782
T.3 Mathematical Relations 784
T.4 The Sinc Function 787
T.5 Probability Functions 788
T.6 Gaussian Probabilities 790
T.7 Glossary of Notation 792
Solutions to Exercises 794
Answers to Selected Problems 825
Supplementary Reading 832
References 835
Index 839