High quality 0.6/1.2/2.4kbps multi-band LPC speech coding algorithm

In this paper, a new 0.6/1.2/2.4kbps multi-band LPC speech coder is presented. To improve speech quality and reduce the bit rate, a multi-mode residual multistage matrix quantization is developed. Other new techniques for improving the performance include pitch smooth and gain-shape vector quantization for gain quantization. Experimental results show that the speech quality of the proposed speech coder is intelligible with good naturalness.