| 摘要 |
PURPOSE: To prevent deterioration in sound quality due to disorder of periodicity of each frame as to a pulse train by providing a sound source pulse generating means which generates sound source pulses in the case of a voiceless sound frame. CONSTITUTION: At the time of encoding, a digitized voice signal is stored in a buffer memory 1 by one frame and converted by a linear predicting circuit 3 into a parameter 4 representing a spectrum envelope. A voiced/voiceless sound decision circuit 9 outputs a decision result 10a showing whether the frame is a voiced sound frame or a voiceless sound frame and a signal 10b indicating switching from the voiceless sound frame to the voiced sound frame. A sound source generation part 11 generates sound source pulses according to the voiced/ voiceless sound decision result 10a and switching signal 10b and outputs its information 12. Consequently, the sound source pulse train is generated without disordering the periodicity that the original voice has, so the sound quality is prevented from deteriorating owing to the disorder of periodicity and the quality of an encoded voice is improved. |
