| 摘要 |
PURPOSE:To obtain a reproduced sound of high quality by dividing sound data into frames with fixed length, detecting that each frame is a silent section, a silent consonant section, a steady vowel section, or a non-steady section, and then thinning or interpolating the frame in accordance with the detected result. CONSTITUTION:A sound signal is transferred from an input buffer 3 to a silence detecting part 4 in each frame. The detecting part 4 calculates the power of a signal corresponding to the frame and the number of times of zero-crossing, and when the value is a threshold or more, regards the frame as the non-steady section (c) or the steady vowel section (d) and transfers the signal to a steady discriminating part 5. When less than the threshold, the frame is regarded as the silent section (a) or the silent consonant section and transferred to an interpolation/thinning part 7. The discriminating part 5 claculates the coefficient of self-correlation of the sound signal, and when the maximum value is larger or less than the threshold, regards the signal as the section (d) and transfers the signal to a reference period extracting part 6 or regards the signal as the section (c) and transfers the signal to an output buffer 9. The extracting part 6 calculates the reference period T of the voice signal from the coefficient providing said maximum value and transfers the period T together with the sound data to the interpolation/thinning part 7. The part 7 executes interpolation or thinning corresponding to the reproducing speed in each period T. |
