| 摘要 |
<p>PURPOSE:To provide delicate variation in timbre by measuring the strength of an attack by an optical method and automatically selecting a timbre sound source which has specific sound volume and timbre among many kind of timbre sound sources which are previously stored according to the measurement information. CONSTITUTION:Assuming that a key A4 among keys 10 is touched, the A4 scale adjusting block VCO of a standard sound source circuit 5 is switched by the closure of a switch and the signal of a sound source A4 is sent out. The scale frequency signal is sent to a key number discriminating circuit 6 and key number position information A4 is detected by a frequency detector 60 and a key number position code oscillator 61 and inputted to an automatic sound source selecting circuit 7. The key A4, on the other hand, is moved down by the touch and an optical path B is cut off. The light shielding is outputted as an electric signal from the O/E terminal unit 30 of a photodetector 3 and inputted to the gate circuit 40 of a light shielding time measurement part 4 and the light shielding time is measured on a pulse counter basis, encoded by a code oscillator 42, and sent to the automatic sound source selecting circuit 7.</p> |
