| 摘要 |
PURPOSE:To reduce a cost and a noise by providing an A/D converter to detect the generation of a sound, a power detecting means and a zero-cross detecting means and starting the accumulation of the sound through the power detecting means and the zero-cross detecting means. CONSTITUTION:An MPU 27 stores the polarity bit of the highest order of the output of an A/D converter 25 to an area 280 and a digital value to be lower than the polarity bit and a constant are compared and stored to an area 281. Next, when the data of areas 280 and 281 are more than an (n) number and the change of '1' and '0' is larger than a K-number concerning the contents of the area 280, it is judged that the starting edge of the sound is detected, and accumulated. When the '1' is more than an (m) number concerning the contents of the area 281, it is judged that the starting edge is detected. Next, dummy data are successively read for a reproducing processing start and decoded through a cordic 24. Thus, the cost and noise are reduced and the self- diagnosis of an accumulating and reproducing can be executed. |
