| 摘要 |
A Communication system e.g. mobile radio using vector quantisation techniques for speech processing includes reference signals arranged in an original element list 70 of a codebook e.g. in a speech coding-decoding arrangement. The system utilises extra resources in the system in the form of extra data bits, free time slots, frequency channels or spreading codes for extending the resolution of the codebook. Based on the extra resources received, a space representing at least a first portion 72 of the original element list is divided into space representing at least two sub-lists 76. A full VQ (vector quantisation) codebook is progressively divided into sub-codebooks and a centroid, i.e. a fixed vector, is calculated for each sub-codebook from the centroid of the original list or codebook. Upon receiving an input signal a codebook index is allocated using a centroid of the original codebook together with a centroid of at least one extended codebook or sub-codebook to reference the optimum centroid for the received signal. |
