US 5,371,853 AGranted

Method and system for CELP speech coding and codebook for use therewith

AssigneeUniversity of Maryland at College Park

InventorsYuhung Kao, John Baras

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Abstract

Apparatus and method for encoding speech using a codebook excited linear predictive (CELP) speech processor and an algebraic codebook for use therewith. The CELP speech processor receives a digital speech input representative of human speech and performs linear predictive code analysis and perceptual weighting filtering to produce a short term speech information and a long term speech information. The CELP speech processor utilizes an organized, non-overlapping, algebraic codebook containing a predetermined number of vectors, uniformly distributed over a multi-dimensional sphere to generate a remaining speech residual. The short term speech information, long term speech information and remaining speech residual are combinable to form a quality reproduction of the digital speech input.

Claims22

Dependent claims

A codebook excited linear predictive (CELP) speech processor comprising:

means for supplying a digital speech input representative of human speech;
means for performing linear predictive code analysis and perceptual weight filtering on said digital speech input to obtain short term speech information;
means for performing linear predictive code analysis and perceptual weight filtering on said digital speech input to obtain long term speech information;
a deterministic non-overlapping codebook of a first predetermined number of vectors which are uniformly distributed over a multi-dimensional sphere, each of the first predetermined number of vectors being partitioned into a second predetermined number of sub-vectors, a substantial number of elements of each of the second predetermined number of sub-vectors being defined as zero, and a remaining even number of elements of each of the second predetermined number of sub-vectors defined as +1 or -1, wherein four elements with an index=5N (where N is an integer from 0 to 3) are non-zero for each of the second predetermined number of subvectors and the four non-zero elements of each of the second predetermined number of sub-vectors are all -1, all +1, or two are -1 and two are +1;
and
means for generating a remaining speech residual of the digital speech input from the deterministic codebook;
the short term speech information, the long term speech information and the remaining speech residual being combinable to form a quality reproduction of the digital speech input to reproduce the human speech represented by said digital speech input.

4 more elements

A method of encoding speech data including the steps of providing a digital speech input, performing linear predictive code analysis and perceptual weight filtering on the digital speech input to produce a short and long term speech information and generating a deterministic non-overlapping codebook of a first predetermined number of vectors which are uniformly distributed over a multi-dimensional sphere comprising the steps of:

a) partitioning each of the first predetermined number of vectors into a second predetermined number of sub-vectors;
b) setting a substantial number of elements of each of the second predetermined number of sub-vectors to zero;
c) setting a remaining even number of elements of each of the second number of sub-vectors to 1 or -1, wherein four elements with an index of SN (where N is an integer from 0 to 3) are non-zero for each of the second number of sub-vectors and the four non-zero elements of each sub-vector are all -1, all +1, or two are -1 and two are +1;
and
d) generating a remaining speech residual of the digital speech input from the deterministic codebook such that the short and long term speech information and the remaining speech residual are combinable to form a quality reproduction of the digital speech input.

2 more elements

Dependencies are inferred from the claim text.