| 摘要 |
PROBLEM TO BE SOLVED: To quickly detect pitch against chopper rendition in a base synthesizer. SOLUTION: A vibration waveform is converted to digital data by an AD converter 2 to input to a first wave detecting part 3 and a peak detecting part 4. The output signal of a first wave is detected by the first wave detecting part 3, and the polarity of the output signal is judged by a chopper detecting part 5. When the polarity is negative, as chopper detection, a pitch detecting part 7 is changed from an ordinary mode to a chopper mode by a pitch detection control part 6. The inclination of the zero cross point of the output signal is detected by the peak detecting part 4, and stored in order in a peak memory part 8. Pitch is detected based on the peak of the peak memory part 8 in the ordinary mode by the pitch detecting part 7. In the chopper mode, the maximum peak at the beginning after the first one is made invalid, and the pitch is deteced from the next peak of the invalid data. |
