| 摘要 |
PROBLEM TO BE SOLVED: To superpose additive information on an analog sound signal without deteriorating the S/N of the sound signal. SOLUTION: A part that is equal to or higher than a prescribed level is detected out of an input analog sound signal S by an envelope detecting part 11, and its output is supplied at the point of time when this part is detected, to a controller 13. The input analog sound signal S is spectrum-analyzed immediately before the point of time of attack detection timing by a spectrum analyzing part 12 to detect out a noncontinuous part to some extent in the spectrum, i.e., a part of wide band frequency distribution. Then, data showing its detected result are supplied to the controller 13. A waveform rewriting part 15 is instructed by the controller 13 to execute rewriting while using a wider area than the gap width. |
