Improved Excitation Sequence Quantization in Regular Pulse Excitation Speech Coding

Good quality speech coding at bit rates under 16 kbps has a growing number of applications for efficient digital transmission and storage. Traditional waveform coders can provide good quality encoded speech at bit rates above 16 kbps, but their performance drops rapidly for lower rates. On the other hand, traditional vocoder techniques enable one to encode speech at very low rates, but the perceptual quality is limited, even for relatively large bit rates (4 to 9.6 kbps).