| 摘要 |
PURPOSE:To adjust a sound source gain so as to suppress acoustic deterioration even though the number of repetition is increased by performing the changes in gain adjustment factors in terms of a subframe unit. CONSTITUTION:The device is provided with a voice coder 40, an error detection coder 41, an error correction coder 42, a transmission line 43, an error correction coder decoder 44, an error detection coder decoder 45, a voice parameter decoder 46, a parameter repeater utilization non-utilization mode changeover switch 49, a parameter repeater 47 and a voice decoder 48. An adaptive sound source gain is adjusted to the value close to 1 during the initial phase of repetition and after that, the gain is attenuated. On the other hand, a statistical sound source gain is adjusted to zero during the initial phase of repetition and after that, the adjustment is made so that the ratio corresponding to the function, which is monotonously increased to a maximum value less than 1 and then, is monotonously decreased, is multiplied to the statistical sound source gain in an error free frame. Moreover, each adjustment factor is updated for every subframe. Thus, repetition method is obtained with less amount of acoustic deterioration even though repetition processes are continuously made. |
