| 摘要 |
Keys (10a, 10b), which are incorporated in an automatic player piano (1), are monitored with an optical transducer system (18); the optical transducer system (18) includes sensor heads (221, 222) provided on both sides of the key trajectories, LEDs (224-1 - 224-12) connected to predetermined sensor heads (221) through optical fibers (24), LDDs (225-1 - 225-8) connected to the other sensor heads (222) through optical fibers (25) and a controlling unit (19); a luminescence controller (140) is connected to the LEDs (224-1 - 224-12) for optimizing the luminescence (led(x)), and bias controllers (230-1 - 230-8) are respectively connected to the LDDs (225-1 - 225-8); the luminescence controller (140) and bias controllers (230-1 - 230-8) optimize the luminescence (led(x))of emitted light and the bias level of electric signals (CHO(Yn)) so that the optical transducer system (18) is free from the individuality of component parts and aged deterioration. |
