CHAPTER 1 Introduction 1
1.1 What Is a Signal? 1
1.2 What Is a System? 2
1.3 Overview of Specific Systems 2
1.4 Classification of Signals 16
1.5 Basic Operations on Signals 25
1.6 Elementary Signals 34
1.7 Systems Viewed as Interconnections of Operations 53
1.8 Properties of Systems 55
1.9 Noise 68
1.10 Theme Examples 71
1.11 Exploring Concepts with MATLAB 80
1.12 Summary 86
Further Reading 86
Additional Problems 88
CHAPTER 2 Time-Domain Representations of Linear Time-Invariant Systems 97
2.1 Introduction 97
2.2 The Convolution Sum 98
2.3 Convolution Sum Evaluation Procedure 102
2.4 The Convolution Integral 115
2.5 Convolution Integral Evaluation Procedure 116
2.6 Interconnections of LTI Systems 127
2.7 Relations between LTI System Properties and the Impulse Response 133
2.8 Step Response 139
2.9 Differential and Difference Equation Representations of LTI Systems 141
2.10 Solving Differential and Difference Equations 147
2.11 Characteristics of Systems Described by Differential and Difference Equations 156
2.12 Block Diagram Representations 161
2.13 State-Variable Descriptions of LTI Systems 167
2.14 Exploring Concepts with MATLAB 175
2.15 Summary 181
Further Reading 182
Additional Problems 183
CHAPTER 3 Fourier Representations of Signals and Linear Time-Invariant Systems 195
3.1 Introduction 195
3.2 Complex Sinugoids and Frequency Response of LTI Systems 196
3.3 Fourier Representations for Four Classes of Signals 199
3.4 Discrete-Time Periodic Signals: The Discrete-Time Fourier Series 202
3.5 Continuous-Time Periodic Signals: The Fourier Series 215
3.6 Discrete-Time Nonperiodic Signals: The Discrete-Time Fourier Transform 230
3.7 Continuous-Time Nonperiodic Signals: The Fourier Transform 241
3.8 Properties of Fourier Representations 253
3.9 Linearity and Symmetry Properties 254
3.10 Convolution Property 259
3.11 Differentiation and Integration Properties 270
3.12 Time- and Frequency-Shift Properties 280
3.13 Finding Inverse Fourier Transforms by Using Partial-Fraction Expansions 286
3.14 Multiplication Property 291
3.15 Scaling Properties 299
3.16 Parseval Relationships 303
3.17 Time-Bandwidth Product 305
3.18 Duality 307
3.19 Exploring Concepts with MATLAB 312
3.20 Summary 320
Further Reading 321
Additional Problems 322
CHAPTER 4 Applications of Fourier Representations to Mixed Signal Classes 341
4.1 Introduction 341
4.2 Fourier Transform Representations of Periodic Signals 342
4.3 Convolution and Multiplication with Mixtures of Periodic and Nonperiodic Signals 348
4.4 Fourier Transform Representation of Discrete-Time Signals 358
4.5 Sampling 362
4.6 Reconstruction of Continuous-Time Signals from Samples 371
4.7 Discrete-Time Processing of Continuous-Time Signals 382
4.8 Fourier Series Representations of Finite-Duration Nonperiodic Signals 389
4.9 The Discrete-Time Fourier Series Approximation to the Fourier Transform 396
4.10 Efficient Algorithms for Evaluating the DTFS 404
4.11 Exploring Concepts with MATLAB 408
4.12 Summary 411
Further Reading 412
Additional Problems 413
CHAPTER 5 Application to Communication Systems 425
5.1 Introduction 425
5.2 Types of Modulation 425
5.3 Benefits of Modulation 429
5.4 Full Amplitude Modulation 431
5.5 Double Sideband-Suppressed Carrier Modulation 440
5.6 Quadrature-Carrier Multiplexing 445
5.7 Other Variants of Amplitude Modulation 446
5.8 Pulse-Amplitude Modulation 451
5.9 Multiplexing 455
5.10 Phase and Group Delays 460
5.11 Exploring Concepts with MATLAB 464
5.12 Summary 474
Further Reading 475
Additional Problems 476
CHAPTER 6 Representing Signals by Using Continuous-TimeComplex Exponentials: the Laplace Transform 482
6.1 Introduction 482
6.2 The Laplace Transform 482
6.3 The Unilateral Laplace Transform 490
6.4 Properties of the Unilateral Laplace Transform 491
6.5 Inversion of the Unilateral Laplace Transform 496
6.6 Solving Differential Equations with Initial Conditions 501
6.7 Laplace Transform Methods in Circuit Analysis 506
6.8 Properties of the Bilateral Laplace Transform 509
6.9 Properties of the Region of Convergence 512
6.10 Inversion of the Bilateral Laplace Transform 516
6.11 The Transfer Function 520
6.12 Causality and Stability 523
6.13 Determining the Frequency Response from Poles and Zeros 528
6.14 Exploring Concepts with MATLAB 541
6.15 Summary 544
Further Reading 546
Additional Problems 546
CHAPTER 7 Representing Signals by Using Discrete-Time Complex Exponentials: the z-Transform 553
7.1 Introduction 553
7.2 The z-Transform 553
7.3 Properties of the Region of Convergence 561
7.4 Properties of the z-Transform 566
7.5 Inversion of the z-Transform 572
7.6 The Transfer Function 579
7.7 Causality and Stability 582
7.8 Determining the Frequency Response from Poles and Zeros 588
7.9 Computational Structures for Implementing Discrete-Time LTI Systems 594
7.10 The Unilateral z-Transform 598
7.11 Exploring Concepts with MATLAB 602
7.12 Summary 606
Further Reading 606
Additional Problems 607
CHAPTER 8 Application to Filters and Equalizers 614
8.1 Introduction 614
8.2 Conditions for Distortionless Transmission 614
8.3 Ideal Low-Pass Filters 616
8.4 Design of Filters 623
8.5 Approximating Functions 624
8.6 Frequency Transformations 630
8.7 Passive Filters 633
8.8 Digital Filters 634
8.9 FIR Digital Filters 635
8.10 IIR Digital Filters 645
8.11 Linear Distortion 649
8.12 Equalization 650
8.13 Exploring Concepts with MATLAB 653
8.14 Summary 658
Further Reading 659
Additional Problems 660
CHAPTER 9 Application to Linear Feedback Systems 663
9.1 Introduction 663
9.2 What Is Feedback? 663
9.3 Basic Feedback Concepts 666
9.4 Sensitivity Analysis 668
9.5 Effect of Feedback on Disturbance or Noise 670
9.6 Distortion Analysis 671
9.7 Summarizing Remarks on Feedback 673
9.8 Operational Amplifiers 673
9.9 Control Systems 679
9.10 Transient Response of Low-Order Systems 682
9.11 The Stability Problem 685
9.12 Routh-Hurwitz Criterion 688
9.13 Root Locus Method 692
9.14 Nyquist Stability Criterion 700
9.15 Bode Diagram 707
9.16 Sampled-Data Systems 711
9.17 Exploring Concepts with MATLAB 721
9.18 Summary 725
Further Reading 725
Additional Problems 727
CHAPTER 10 Epilogue 737
10.1 Introduction 737
10.2 Speech Signals: An Example of Nonstationarity 738
10.3 Time-Frequency Analysis 739
10.4 Nonlinear Systems 750
10.5 Adaptive Filters 757
10.6 Concluding Remarks 760
Further Reading 760
APPENDIX A Selected Mathematical Identities 763
A.1 Trigonometry 763
A.2 Complex Numbers 764
A.3 Geometric Series 765
A.4 Definite Integrals 765
A.5 Matrices 766
APPENDIX B Partial-Fraction Expansions 767
B.1 Partial-Fraction Expansions of Continuous-TimeRepresentations 767
B.2 Partial-Fraction Expansions of Discrete-TimeRepresentation 770
APPENDIX C Tables of Fonrier Representations and Properties 773
C.1 Basic Discrete-Time Fourier Series Pairs 773
C.2 Basic Fourier Series Pairs 774
C.3 Basic Discrete-Time Fourier Transform Pairs 774
C.4 Basic Fourier Transform Pairs 775
C.5 Fourier Transform Pairs for Periodic Signals 775
C.6 Discrete-Time Fourier Transform Pairs for Periodic Signals 776
C.7 Properties of Fourier Representations 777
C.8 Relating the Four Fourier Representations 779
C.9 Sampling and Aliasing Relationships 779
APPENDIX D Tables of Laplace Transforms and Properties 781
D.1 Basic Laplace Transforms 781
D.2 Laplace Transform Properties 782
APPENDIX E Tables of z-Tansforms and Properties 784
E.1 Basic z-Transforms 784
E.2 z-Transform Properties 785
APPENDIX F Introduction to MATLAB 786
F.1 Basic Arithmetic Rules 786
F.2 Variables and Variable Names 787
F.3 Vectors and Matrices 787
F.4 Plotting in MATLAB 789
F.5 M-files 790
F.6 Additional Help 791
INDEX 793