Digital Speech: Coding for Low Bit Rate Communication Systems
Building on the success of the first edition Digital Speech offers extensive new, updated and revised material based upon the latest research. This Second Edition continues to provide the fundamental technical background required for low bit rate speech coding and the hottest developments in digital speech coding techniques that are applicable to evolving communication systems. * Features new chapters on Pitch Estimation and Voice--Unvoiced Classification of Speech, Harmonic Speech Coding and Multimode Speech Coding * Presents a comprehensively revised chapter entitled Analysis by Synthesis LPC Coding including specific examples of popular speech coders such as CELP (Code--Excited Linear Predictive) Coding * Contains an updated chapter on Efficient LPC Quantization Methods including MSVQ and anti--aliasing filtering * Discusses Voice Activity Detection (VAD) methods * Offers expanded coverage of speech enhancement techniques such as echo cancellation and noise suppression Written by a well--known, highly respected academic, this authoritative volume will be invaluable to practising engineers, network designers, computer scientists and advanced students in communications, electrical and electronic engineering.
Why Read This Book
You should read this book if you need a hands-on, algorithm-level guide to low bit-rate speech coding: it explains core models (LPC), popular coder architectures (including CELP), and practical topics such as pitch estimation, voice/unvoiced classification, and quantization. You will get both the theoretical background and algorithm descriptions that make it possible to implement and evaluate real-world speech coders.
Who Will Benefit
Engineers and graduate students working on speech/audio codec design, communications engineers building low-bit-rate voice systems, or DSP practitioners needing implementation-level details of modern speech coders.
Level: Intermediate — Prerequisites: Basic digital signal processing (discrete-time signals, linear systems, z-transform), familiarity with digital filters and sampling, and comfort reading algorithm descriptions; basic probability/estimation knowledge is helpful.
Key Takeaways
- Explain and apply linear predictive coding (LPC) analysis-by-synthesis and its role in low-bit-rate speech coding.
- Design and implement code-excited linear prediction (CELP) style coders and understand their perceptual motivations.
- Estimate pitch and perform voice/unvoiced classification robustly for coder front-ends.
- Implement harmonic and multimode speech coding methods for mixed voiced/unvoiced signals.
- Apply efficient quantization strategies including multistage/vector quantization (MSVQ) and bit-allocation techniques.
- Evaluate coder performance using perceptual and objective measures and understand error-resilience considerations.
Topics Covered
- 1. Introduction to Speech Coding and Low Bit-Rate Requirements
- 2. Speech Production Models and Signal Representation
- 3. Linear Predictive Coding: Theory and Analysis-by-Synthesis
- 4. LPC Quantization Methods and Efficient Parameter Coding (including MSVQ)
- 5. Pitch Estimation and Voice/Unvoiced Classification
- 6. Code-Excited Linear Prediction (CELP) and Variants
- 7. Harmonic Speech Coding Methods
- 8. Multimode Speech Coding and Mode Selection
- 9. Bit-Rate Control, Bit Allocation, and Rate-Distortion Tradeoffs
- 10. Error Resilience, Channel Considerations and Packet Loss
- 11. Perceptual Evaluation and Quality Measures
- 12. Standards, Applications and Implementation Issues
- Appendices: Mathematical Background and Implementation Notes
Languages, Platforms & Tools
How It Compares
More implementation-focused on low-bit-rate speech coding than Deller/Proakis/Hansen's Discrete-Time Speech Signal Processing (which is broader DSP), and more application-oriented than the edited collection Speech Coding and Synthesis (Kleijn & Paliwal), which surveys many research topics.
