Multiple stage vector quantization for speech coding

In this paper, we present a multiple stage vector quantization technique which allows easy expansion of the original vector quantizer design to operate at higher bit rates for lower distor-tion. The computation and storage reduction is achieved by the fact that the overall requirements are the sum of the requirenierts of each stage ins-tead of an exponentially increasing function of the bit rate as in the original one stage design. In the case of Euclidean distance measures such as the log area ratio measure, experimental re— suits show that the quantizer performance is very close to a theoretically predicted asymptotically optimal rate distortion relationship. I