Patent ID: 7006966
Filing Date: 2006-02-28
Classification: G10L

Abstract:
1. A speech encoding apparatus comprising: a spectral envelope information encoding unit for extracting spectral envelope information on an input speech, and encoding the spectral envelope information; an excitation information encoding unit for, by use of said spectral envelope information extracted by said spectral envelope information encoding unit, determining adaptive excitation code, fixed excitation code, and gain code with which an encoding distortion of a synthesized speech to be generated is minimized; and a multiplexer for multiplexing said spectral envelope information encoded by said spectral envelope information encoding unit and said adaptive excitation code, said fixed excitation code, and said gain code each determined by said excitation information encoding unit so as to output speech code; wherein said excitation information encoding unit includes: a fixed excitation encoding unit for evaluating encoding distortions of fixed code vectors stored in a plurality of fixed excitation code books to determine said fixed excitation code; a first periodicity providing unit for, when said encoding distortions of said fixed code vectors are evaluated, emphasizing periodicity of a fixed code vector output from at least one fixed excitation code book by use of a first periodicity emphasis coefficient adaptively determined based on a predetermined rule; and a second periodicity providing unit for emphasizing periodicity of a fixed code vector output from at least one fixed excitation code book by use of a fixed second periodicity emphasis coefficient.