| 摘要 |
The keyboard for electronic musical instruments provides a solenoid coil (4) for every key (1), which is excited with pulse-width modulated signals by a control circuit (8). A plunger (5) of the solenoid is coupled mechanically with the key, respectively. When the solenoid coil is being excited, the plunger (5) pushes the key (1) towards an upper limit position. Furtheron, the solenoid coil serves as a sensor for the measuring of the key position by evaluation of the progress of the electric current through the solenoid coil, or by evaluating the reverse-bias voltage induced by the coil of the solenoid (4) during the pulse pauses of the control signal. The control circuit (8) changes the pulse width of the control signals dependent on the sensed position, whereby the key characteristics can be modified.
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