| 摘要 |
The present invention discloses a method of improving the coded speech quality in low bit rate analysis-by-synthesis (AbS) speech coders. This is accomplished by relaxing the waveform matching constraints for non-stationary plosive speech segments of speech signals by suitably shifting pulse locations of the coded excitation signal. The shifting results in the coded signal having phase information that does not exactly match original signal in places where it is perceptually insignificant to the listener. Furthermore, a technique for adaptive phase dispersion is introduced to the coded excitation signal to efficiently preserve important signal characteristics such as the energy spread of the original signal. |
