A novel split residual vector quantization scheme for low bit rate speech coding

For low bit rate linear predictive speech coding, it is desirable to quantize the LPC parameters using as few bits as possible with transparent quantization quality. A novel structural constrained vector quantization scheme, namely split residual vector quantization (SRVQ), is proposed. In this scheme, PARCOR coefficient vector is split into subvectors and each subvector is sequentially quantized according to a multi-stage structure based on the principle of minimizing the prediction error energies. Simulation results show that a 2-stage split residual vector quantizer can achieve transparent quantization at 25 bit/frame while autocorrelation analysis is employed to calculate the LPC parameters