Process and device for minimizing an error in a speech signal using a residue signal and a synthesized excitation signal

A method for processing a speech signal with a closed loop long term prediction mechanism, comprising the steps of:

• transducing an acoustic signal to generate a digital speech input signal;
• processing said digital speech input signal with a processing mechanism to obtain a residue signal, r(n);
• obtaining a synthesis excitation signal e(n-.lambda.) which is continuous at a beginning of a subblock;
• calculating an error expression e(n)=h.sub.g (n)*(r(n)-.beta.e(n-.lambda.)), where .beta. is an optimum gain associated with each delay, .lambda., of a set of delays, and h.sub.g (n) is a transfer function of a perceptual filter mechanism, wherein
• said calculating step comprising the step of minimizing an error based on said error expression, e(n).

A speech processing system comprising:

• means for obtaining a residue signal, r(n), from a speech signal that is input to said speech processing system;
• means for obtaining a synthesis excitation signal e(n-.lambda.) which is continuous at a beginning of a subblock;
• means for calculating an error expression e(n)=h.sub.g (n)*(r(n)-.beta.e(n-.lambda.)), where .beta. is an optimum gain associated with each delay, .lambda., of a set of delays, and h.sub.g (n) is a transfer function of a perceptual filter mechanism;
• and
• said means for calculating comprising means for minimizing an error based on said error expression, e(n).

A speech processing system comprising:

• a transducer that converts an acoustic signal to a digital speech input signal;
• means for processing said digital speech input signal to obtain a residue signal, r(n);
• means for obtaining a synthesis excitation signal e(n-.lambda.) which is continuous at a beginning of a subblock;
• and
• a closed loop long term predication mechanism, comprising means for calculating an error expression e(n)=h.sub.g (n)*(r(n)-.beta.e(n-.lambda.)), where .beta. is an optimum gain associated with each delay, .lambda., of a set of delays, and h.sub.g (n) is a transfer function of a perceptual filter mechanism, wherein
• said means for calculating comprises means for minimizing an error based on said error expression, e(n).