| 摘要 |
PURPOSE:To optimize a statistical excitation code vector so that a total distor tion becomes small enough by synthesizing an adaptive excitation code vector whose high frequency component is attenuated and the statistical excitation code vector, at the time of encoding processing of an input voice vector. CONSTITUTION:As for an adaptive excitation code vector Va from an adaptive excitation code book 20, its high frequency component is eliminated by a low- pass filter 22, and its vector VL is multiplied by an amplitude coefficient (g) in a multiplier 23 and given to an adder 24. On the other hand, a statistical excitation code vector Vs from a statistical excitation code book 21 is multiplied by an amplitude coefficient (gs) in a multiplier 25 and given to the adder 24. Subsequently, a composite vector V of the vectors VL and Vs whose amplitude is adjusted is obtained by the adder 24. In such a way, by varying a frequency part of the vectors VL and Vs in the vector V, a variation of the vector Va is made not to influence to the utmost an optimization processing. |
