| 摘要 |
<p>A CPU provides control instructions according to key switch information supplied from a keyboard. An LSI receives the control instructions and generates a corresponding digital tone signal, which is converted in an acoustic system into an analog tone signal which is in turn supplied to a loudspeaker for producing sound. A power supply unit can be connected to the LSI and acoustic system through a transistor. The transistor is on-off controlled according to a power-off signal which is provided from the CPU according to a silent state signal generated from a power saving circuit in the LSI.</p> |
