PURPOSE: To constitute extremely high reconstituted speech quality at a low bit rate by speedy search technology in a coder and using a vector excited code book which is smaller and optimized.

CONSTITUTION: Pulse vector excited coding(PVXC) is previously calculated and discriminated from another excited coder by using (scattered) code vectors of pulse patterns in a stored group. The type of glottis model excitation is used together with a scattered vector speedy search (SVFS) and an effective error minimizing mechanism of an increased SVFS complexity reducing method and the excitation code book which is optimized to minimize a weighting error between the original and reconstituted speech waveforms is incorporated in the PVXC. An optimizing procedure is based upon centroid derivation. Consequently, the complexity of speech code technology of the vector excitation coding (VXC) can be reduced without sacrificing the perceptual quality of a reconstituted speech signal.