公开(公告)号：US20040039567A1

公开(公告)日：2004-02-26

申请号：US10227725

申请日：2002-08-26

Applicant: MOTOROLA, INC.

Inventor： Mark A. Jasiuk

IPC: G10L019/12

CPC classification number: G10L19/12 ,  G10L19/135 ,  G10L2019/0013

Abstract: A codebook excited linear prediction coding system providing improved digital speech coding for high quality speech at low bit rates with side-by-side codebooks for segments of the modeled input signal to reduce the complexity of the codebook search. A linear predictive filter responsive to an input signal desired to be modeled is used for identifying a basis vector from a first codebook over predetermined intervals as a subset of the input signal. A long term predictor and a vector quantizer provide synthetic excitation of modeled waveform signal components corresponding to the input signal desired to be modeled from side-by-side codebooks by providing codevectors with concatenated signals identified from the basis vector over the predetermined intervals with respect to the side-by-side codebooks. Once a codevector is identified, the codebook at the next segment is searched and a concatenation of codevectors is provided by selecting up to but not including the current segment. The codevector is treated as an additional basis vector for the codebook search at the current segment. It is possible to significantly reduce the complexity of the VSELP codebook search by precomputing and storing the terms for the code search that do not change from segment to segment. Using these techniques, the complexity of searching a 45 bit VSELP codebook (Nnull40, Mnull45, Mnullnull9, Jnull5) was found to be approximately equivalent to searching a traditionally structured 10 bit VSELP codebook (Nnull40, Mnull10, Jnull1). A concatenation of codevectors or carry-along basis vectors are formed as a concatenation of VSELP codevectors selected up to but not including the current segment.

Abstract translation: 码本激励线性预测编码系统，以低比特率的高质量语音提供改进的数字语音编码，并行编码用于建模输入信号的段，以降低码本搜索的复杂度。 响应于期望被建模的输入信号的线性预测滤波器被用于通过预定间隔从第一码本识别基本矢量作为输入信号的子集。 长期预测器和矢量量化器提供对与期望由并排码本建模的输入信号相对应的建模波形信号分量的综合激励，该码矢量相对于预定间隔，通过从基矢量识别的级联信号， 并排的码本。 一旦识别了码矢量，则搜索下一段的码本，并通过选择直到但不包括当前段来提供代码矢量的级联。 代码向量被视为当前段的码本搜索的附加基本向量。 通过预先计算和存储不从段到段的代码搜索的术语，可以显着降低VSELP码本搜索的复杂度。 使用这些技术，发现搜索45位VSELP码本（N = 40，M = 45，M'= 9，J = 5）的复杂度大致相当于搜索传统结构的10位VSELP码本（N = 40 ，M = 10，J = 1）。 代码矢量或携带方向矢量的级联形成为直到但不包括当前段的VSELP码矢量的级联。