| 摘要 |
PURPOSE:To contrive the improvement of a voice quality even in a low bit rate by switching and quantizing in accordance with the pitch correlation of an input sound signal by two code books being a optimum to each, in the case when the periodicity of an input voice is strong and in other case. CONSTITUTION:In an encoding part (a), a vector generating part 7 fetches and outputs a vector from a first code book 91 and a second code book 92, in the case when it is shown that a pitch correlation coefficient is large and in other case, respectively, by a vector number and a long-term prediction switching signal inputted from an optimum vector selecting part 8. Also, in a decoding part (b) of an encoded signal, a vector generating part 15 fetches and outputs a vector from a first code book 181 and a second code book 182, in the case when it is shown that the pitch correlation coefficient is large and in other case, respectively, by an optimum vector number and a long-term prediction switching signal. In such a way, the quality of a satisfactory sound signal is obtained even in a low bit rate. |
