Key-touch strength changing circuit for automatic playing piano

Abstract

Abstract PURPOSE: To change the key-touch strength, by changing the duty ratio of the solenoid drive signal in pulse nature fed to the drive circuit of hammer mechanism with the digital signal from external side. CONSTITUTION: The clock pulse signal a produced from the clock generating circuit 1 is frequency-divided and the timing control signal b is output from the timing control circuit 2. The said control signal b rises the key-touch timing pulse d at the key-touch timing hold circuit 4 and the signal from the key-touch strength information circuit 7 is preset to the preset counter 3. At the preset counter 3, when the preset value in response to the key number at each playing is counted, the reset signal c of the key-touch timing pulse d is fed to the key-touch timing hold circuit 4, and the output pulse width is digitally determined. As a result, the key-touch pulse d is changed for the pulse width with the instruction from external key-touch strength information, allowing to change the key-touch strength easily. COPYRIGHT: (C)1981,JPO&Japio

Inventors

• 👤 Zenichi Kawanaka

Bibliographic Details