NOISE FEEDBACK CODING METHOD AND SYSTEM FOR PERFORMING GENERAL SEARCHING OF VECTOR QUANTIZATION CODEVECTORS USED FOR CODING A SPEECH SIGNAL

A method of searching a plurality of Vector Quantization (VQ) codevectors for a preferred one of the VQ codevectors to be used as an output of a vector quantizer for encoding a speech signal, includes determining a quantized prediction residual vector, and calculating a corresponding unquantized prediction residual vector and the energy of the difference between these two vectors (that is, a VQ error vector). After trying each of the plurality of VQ codevectors, the codevector that minimizes the energy of the VQ error vector is selected as the output of the vector quantizer