| 摘要 |
PURPOSE:To prevent the increment of the power consumption for the electronic desk computer featuring the musical sound generating function by stopping the generation of the musical sound in case the key is pushed longer than the fixed time during which no effect is given to the music performance. CONSTITUTION:The key is operated in the music mode, and then the data is sent to musical sound generation part 15 via control part 12 to produce the clock pulse of the specified frequency. At the same time, FF22 is set, and the sound is generated at sound generation part 17 and via the pulse sent from part 15. At and after this moment, counter 24 starts counting. When the key is pressed at the time point when no carry signal is delivered from counter 24, FF22 is reset to stop the generation of the musical sound. If the key is pressed longer than the fixed time and thus the carry signal has been delivered, FF22 is reset with gates 16 and 23 closed. Thus the advance is stopped for counter 24, and at the same time no clock pulse of the fixed frequency is supplied to part 17 from part 15. |
