Digital speech coder having improved vector excitation source

Details Digital speech coder having improved vector excitation source Digital speech coder having improved vector excitation source

1989-01-06

1990-01-23

Kemeny, Emanuel S.

Electrical audio signal processing systems and devices

One-way audio signal program distribution

Public address system

381 49, G10L 500

Patent

active

048963615

ABSTRACT:
An improved excitation vector generation and search technique (FIG. 1) is described for a code-excited linear prediction (CELP) speech coder (100) using a codebook memory of excitation code vectors. A set of M basis vectors v.sub.m (n) are used along with the excitation signal codewords (i) to generate the codebook of excitation vectors u.sub.i (n) according to a "vector sum" technique (120) of converting stored selector codewords into a plurality of interim data signals, multiplying the set of M basis vectors by the interim data signals, and summing the resultant vectors to produce the set of 2.sup.M codebook vectors. Only M basis vectors need to be stored in memory (114), as opposed to all 2.sup.M code vectors.

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