Speech coding system
AssigneeFujitsu Limited
InventorsTomohiko Taniguchi, Mark Johnson
Life of this patent
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Abstract
A speech coding system operated under a known code-excited linear prediction (CELP) coding method. The CELP coding is achieved by selecting an optimum pitch vector P from an adaptive codebook and the corresponding first gain and, at the same time, selecting an optimum code vector from a sparse-stochastic codebook and the corresponding second gain. Special code vectors are loaded in the sparse-stochastic codebook, which code vectors are hexagonal lattice code vectors each consisting of a zero vector with one sample set to +1 and another sample set to -1.
Claims10
A speech coding system constructed under a code-excited linear prediction (CELP) coding algorithm, including:
- an adaptive codebook storing therein a plurality of pitch prediction residual vectors and providing an output;
- a sparse-stochastic codebook storing therein, as white noise, a plurality of code vectors and providing an output;
- first and second gain amplifiers, respectively coupled to said adaptive codebook and said sparse-stochastic codebook, for applying a first gain and a second gain to the outputs from said adaptive and sparse-stochastic codebooks respectively;
- and
- an evaluation unit, coupled to said adaptive and sparse-stochastic codebooks, for selecting optimum vectors and optimum gains which match a perceptually weighted input speech signal, to provide the selected optimum vectors and optimum gains as coded information for each input speech signal,
- said sparse-stochastic codebook being formed as a hexagonal lattice code vector stochastic codebook in which particular code vectors are loaded, said code vectors being hexagonal lattice code vectors each consisting of a zero vector with one sample set to +1 and another sample set to -1.
A speech coding system, comprising:
- an adaptive codebook storing therein a plurality of pitch prediction residual vectors and providing an output;
- a sparse-stochastic codebook storing therein a plurality of code vectors formed as multi-dimensional polyhedral lattice vectors each consisting of a zero vector with one sample set to +1 and another sample set to -1, said sparse-stochastic codebook providing an output;
- and
- an evaluation unit, coupled to said adaptive and sparse-stochastic codebooks, for selecting optimum vectors and optimum gains which match a perceptually weighted input speech signal, to provide the selected optimum vectors and optimum gains as coded information for each input speech signal.
Dependencies are inferred from the claim text.