| 摘要 |
PROBLEM TO BE SOLVED: To encode a vocal analog acoustic signal by MIDI data. SOLUTION: The vocal analog acoustic signal is digitized by a PCM to detect positions of polarity change points expressing local peaks. A higher intrinsic frequency is defined based on a cycle, in which polarity change points having the same polarities appear and a lower intrinsic frequency is defined based on a cycle, in which polarity change points having approximate signal intensities appear. A series of polarity change point group, whose higher intrinsic frequencies are approximate and a series of polarity change point group, whose lower intrinsic frequencies are approximate are respectively defined as unit sections. Higher unit sections Uh (i) and lower unit sections Ul (i) overlap each other on a time base. Representative frequencies and representative intensities are respectively defined in respective unit sections and MIDI data having note numbers corresponding to the representative frequencies and having velocities corresponding to the representative intensities and having delta times corresponding to lengths of the unit sections are defined for every individual unit section. |
