Speech coder and speech decoder

摘要

A dispersed vector generator used in an excitation vector generator for a speech coder/decoder is provided. The dispersed vector generator includes a pulse vector generating section that generates a pulse vector having a signed unit pulse on one element of a vector axis. The dispersed vector generator also includes a dispersion pattern storing section that stores a plurality of dispersion patterns, a switch that selects a dispersion pattern out of the plurality of dispersion patterns stored in the dispersion pattern storing section and a pulse vector dispersion section that generates a dispersed vector by convoluting the selected dispersion pattern and the pulse vector.