Advances in Speech Coding

Speech coding has been an ongoing area of research for several decades, yet the level of activity and interest in this area has expanded dramatically in the last several years. Important advances in algorithmic techniques for speech coding have recently emerged and excellent progress has been achieved in producing high quality speech at bit rates as low as 4.8 kb/s. Although the complexity of the newer more sophisticated algorithms greatly exceeds that of older methods (such as ADPCM), today's powerful programmable signal processor chips allow rapid technology transfer from research to product development and permit many new cost-effective applications of speech coding. In particular, low bit rate voice technology is converging with the needs of the rapidly evolving digital telecom­ munication networks. The IEEE Workshop on Speech Coding for Telecommunications was held in Vancouver, British Columbia, Canada, from September 5 to 8, 1989. The objective of the workshop was to provide a forum for discussion of recent developments and future directions in speech coding. The workshop attracted over 130 researchers from several countries and its technical program included 51 papers.

Contenu

I Introduction.- II Low-Delay Speech Coding.- 1. Backward Adaptive Prediction Algorithms in Multi-Tree Speech Coders.- 2. Backward Adaptive Configurations for Low-Delay Vector Excitation Coding.- 3. A Robust Low-Delay CELP Speech Coder at 16 kb/s.- 4. An Efficient Variable-Bit-Rate Low-Delay CELP (VBR-LD-CELP) Coder.- 5. A Trellis-Searched 16 kbit/sec Speech Coder with Low-Delay.- 6. Hybrid Backward Adaptive Pitch Prediction for Low-Delay Vector Excitation Coding.- III Speech Coding for Digital Cellular and Portable Communications.- 7. Vector Sum Excited Linear Prediction (VSELP).- 8. An Error Protected Transform Coder for Cellular Mobile Radio.- 9. A Multipulse Speech Codec for Digital Cellular Mobile Use.- 10. Transmitting Digital Speech in a Portable Radio Environment.- 11. A Study on Speech and Channel Coding for Digital Cellular.- IV Speech Coding Below 8 kb/s Using Code Excited Linear Prediction.- 12. The DOD 4.8 KBPS Standard (Proposed Federal Standard 1016).- 13. Analysis-by-Synthesis Linear Predictive Speech Coding at 4.8 kbit/s and below.- 14. Binary Pulse Excitation: A Novel Approach to Low Complexity CELP Coding.- 15. Speech Coding with Dynamic Bit Allocation (Multimode Coding).- 16. 7 KBPS-7 MIPS-High Quality ACELP for Cellular Radio.- 17. A 6 KBPS Regular Pulse CELP Coder for Mobile Radio Communications.- V Alternative Techniques for Low Rate Speech Coding.- 18. Beyond Multipulse and CELP Towards High Quality Speech at 4 kb/s.- 19. Sine-Wave Amplitude Coding at Low Data Rates.- 20. The Multi-Band Excitation Speech Coder.- 21. Phonetic Segmentation for Low Rate Speech Coding.- 22. Vector Excitation Homomorphic Vocoder.- 23. A 400-BPS Speech Coding Algorithm for Real-Time Implementation.- VI Speech Coding for Noisy Channels and Real-Time Implementations.- 24. Source-Dependent Channel Coding and its Application to CELP.- 25. Vector Trellis Quantization for Noisy Channels.- 26. Application of Stochastic Coding Schemes in Satellite Communication.- 27. A Real Time Implementation of a 4800 bps Self Excited Vocoder.- 28. A Real-Time Full Duplex 16/8 KBPS CVSELP Coder with Integral Echo Canceller Implemented on a Single DSP56001.- VII Topics in Speech Coding.- 29. Improved Excitation Sequence Quantization in Regular Pulse Excitation Speech Coding.- 30. On Improving the Performance of Pitch Predictors in Speech Coding Systems.- 31. Efficient Encoding of the Long-Term Predictor in Vector Excitation Coders.- 32. Constrained-Stochastic Excitation Coding of Speech at 4.8 kb/s.- 33. Speech Coding Using Least-Squares Estimation.- 34. Qualitative Analysis and Enhancement of Sine Transform Coding.- 35. An ADM Speech Coding with Time Domain Harmonic Scaling.