| 摘要 |
PURPOSE: To reduce the occurrence of mistracking at the time of picking operation by narrowing a pitch extraction sound area limiting range at the start of sound generation, and after generating a sound, extending the range. CONSTITUTION: The attenuation rate of a peak holding circuit in a peak detection circuit PEDT is changed by a time constant conversion control circuit TCC, and when a peak can not be detected even after the lapse of one period e.g. of a waveform, quick attenuation is executed. Namely in an initial state, attenuation is quickly executed after the time lapse of a maximum tone period in order to quickly detect the oscillation of an waveform, and when the oscillation of a string is detected, quick attenuation is similarly executed after the time lapse of an opened string period of the string because a double sound is not picked up. After extracting the oscillation period of the string, quick attenuation is executed by the period. The setting of period information in the circuit TCC is executed by a microcomputer. Consequently the occurrence of mistracking at the time of picking operation can be reduced. |
