Theory and Applications of Digital Speech Processing, 1st edition

CHAPTER 1 Introduction to Digital Speech Processing 1

1.1 The Speech Signal 3

1.2 The Speech Stack 8

1.3 Applications of Digital Speech Processing 10

1.4 Comment on the References 15

1.5 Summary 17

 

CHAPTER 2 Review of Fundamentals of Digital Signal Processing 18

2.1 Introduction 18

2.2 Discrete-Time Signals and Systems 18

2.3 Transform Representation of Signals and Systems 22

2.4 Fundamentals of Digital Filters 33

2.5 Sampling 44

2.6 Summary 56

Problems 56

 

CHAPTER 3 Fundamentals of Human Speech Production 67

3.1 Introduction 67

3.2 The Process of Speech Production 68

3.3 Short-Time Fourier Representation of Speech 81

3.4 Acoustic Phonetics 86

3.5 Distinctive Features of the Phonemes of American English 108

3.6 Summary 110

Problems 110

 

CHAPTER 4 Hearing, Auditory Models, and Speech Perception 124

4.1 Introduction 124

4.2 The Speech Chain 125

4.3 Anatomy and Function of the Ear 127

4.4 The Perception of Sound 133

4.5 Auditory Models 150

4.6 Human Speech Perception Experiments 158

4.7 Measurement of Speech Quality and Intelligibility 162

4.8 Summary 166

Problems 167

 

CHAPTER 5 Sound Propagation in the Human Vocal Tract 170

5.1 The Acoustic Theory of Speech Production 170

5.2 Lossless Tube Models 200

5.3 Digital Models for Sampled Speech Signals 219

5.4 Summary 228

Problems 228

 

CHAPTER 6 Time-Domain Methods for Speech Processing 239

6.1 Introduction 239

6.2 Short-Time Analysis of Speech 242

6.3 Short-Time Energy and Short-Time Magnitude 248

6.4 Short-Time Zero-Crossing Rate 257

6.5 The Short-Time Autocorrelation Function 265

6.6 The Modified Short-Time Autocorrelation Function 273

6.7 The Short-Time Average Magnitude Difference Function 275

6.8 Summary 277

Problems 278

 

CHAPTER 7 Frequency-Domain Representations 287

7.1 Introduction 287

7.2 Discrete-Time Fourier Analysis 289

7.3 Short-Time Fourier Analysis 292

7.4 Spectrographic Displays 312

7.5 Overlap Addition Method of Synthesis 319

7.6 Filter Bank Summation Method of Synthesis 331

7.7 Time-Decimated Filter Banks 340

7.8 Two-Channel Filter Banks 348

7.9 Implementation of the FBS Method Using the FFT 358

7.10 OLA Revisited 365

7.11 Modifications of the STFT 367

7.12 Summary 379

Problems 380

 

CHAPTER 8 The Cepstrum and Homomorphic Speech Processing 399

8.1 Introduction 399

8.2 Homomorphic Systems for Convolution 401

8.3 Homomorphic Analysis of the Speech Model 417

8.4 Computing the Short-Time Cepstrum and Complex Cepstrum

of Speech 429

8.5 Homomorphic Filtering of Natural Speech 440

8.6 Cepstrum Analysis of All-Pole Models 456

8.7 Cepstrum Distance Measures 459

8.8 Summary 466

Problems 466

 

CHAPTER 9 Linear Predictive Analysis of Speech Signals 473

9.1 Introduction 473

9.2 Basic Principles of Linear Predictive Analysis 474

9.3 Computation of the Gain for the Model 486

9.4 Frequency Domain Interpretations of Linear Predictive

Analysis 490

9.5 Solution of the LPC Equations 505

9.6 The Prediction Error Signal 527

9.7 Some Properties of the LPC Polynomial A(z) 538

9.8 Relation of Linear Predictive Analysis to Lossless Tube Models 546

9.9 Alternative Representations of the LP Parameters 551

9.10 Summary 560

Problems 560

 

CHAPTER 10 Algorithms for Estimating Speech Parameters 578

10.1 Introduction 578

10.2 Median Smoothing and Speech Processing 580

10.3 Speech-Background/Silence Discrimination 586

10.4 A Bayesian Approach to Voiced/Unvoiced/Silence Detection 595

10.5 Pitch Period Estimation (Pitch Detection) 603

10.6 Formant Estimation 635

10.7 Summary 645

Problems 645

 

CHAPTER 11 Digital Coding of Speech Signals 663

11.1 Introduction 663

11.2 Sampling Speech Signals 667

11.3 A Statistical Model for Speech 669

11.4 Instantaneous Quantization 676

11.5 Adaptive Quantization 706

11.6 Quantizing of Speech Model Parameters 718

11.7 General Theory of Differential Quantization 732

11.8 Delta Modulation 743

11.9 Differential PCM (DPCM) 759

11.10 Enhancements for ADPCM Coders 768

11.11 Analysis-by-Synthesis Speech Coders 783

11.12 Open-Loop Speech Coders 806

11.13 Applications of Speech Coders 814

11.14 Summary 819

Problems 820

 

CHAPTER 12 Frequency-Domain Coding of Speech and Audio 842

12.1 Introduction 842

12.2 Historical Perspective 844

12.3 Subband Coding 850

12.4 Adaptive Transform Coding 861

12.5 A Perception Model for Audio Coding 866

12.6 MPEG-1 Audio Coding Standard 881

12.7 Other Audio Coding Standards 894

12.8 Summary 894

Problems 895

 

CHAPTER 13 Text-to-Speech Synthesis Methods 907

13.1 Introduction 907

13.2 Text Analysis 908

13.3 Evolution of Speech Synthesis Methods 914

13.4 Early Speech Synthesis Approaches 916

13.5 Unit Selection Methods 926

13.6 TTS Future Needs 942

13.7 Visual TTS 943

13.8 Summary 947

Problems 947

 

CHAPTER 14 Automatic Speech Recognition and Natural

Language Understanding 950

14.1 Introduction 950

14.2 Basic ASR Formulation 952

14.3 Overall Speech Recognition Process 953

14.4 Building a Speech Recognition System 954

14.5 The Decision Processes in ASR 957

14.6 Step 3: The Search Problem 971

14.7 Simple ASR System: Isolated Digit Recognition 972

14.8 Performance Evaluation of Speech Recognizers 974

14.9 Spoken Language Understanding 977

14.10 Dialog Management and Spoken Language Generation 980

14.11 User Interfaces 983

14.12 Multimodal User Interfaces 984

14.13 Summary 984

Problems 985

 

Appendices

A Speech and Audio Processing Demonstrations 993

B Solution of Frequency-Domain Differential Equations 1005

Bibliography 1009

Index 1033