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Abstract

The present invention relates to a device and process for the digital coding and decoding of speech comprising a short term prediction, a long term prediction and a residual wave coding technique using a synthesis analysis method. The LTP analysis module uses a dictionary of delays having a pseudo-logarithmic structure, in which the delays are arranged in increasing order. This dictionary is constituted by segments, each having a given resolution, the resolutions of the successive segments decreasing geometrically in a rational ratio k>1, while the number of elements of each segment remains constant. The invention defines the use of .lambda. delay elements of said dictionary extending the LTP analysis techniques to high time resolution. The invention also relates to a process for the rapid scanning of such a pseudo-logarithmic delay dictionary. It also relates to a process for implementing a selection criterion of the delay in closed loop with perceptual filtering. The invention also relates to scanning a dictionary of delays and calculating a difference between a residue signal and a synthesized delayed residual, and perceptual filtering the difference.

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First Claim