| 摘要 |
PURPOSE:To eliminate a noise signal at application of power by adding an inhibition circuit inhibiting a signal outputted from an audio signal generating circuit until an instruction is given from a central processing unit of a microcomputer to the audio signal generating circuit. CONSTITUTION:A relay circuit 3 is normally in the OFF state, a control signal 7 is given to the audio signal generating circuit 2 from the central processing unit 1 and so long as an instruction or a data is not supplied afterward, no audio signal 8 is outputted. Thus, the control signal 7 is detected by an instruction detecting circuit 5 and a permission signal 10 is given to bring the relay circuit 3 into the ON state, the passing of the audio signal 8 outputted from the audio signal generating circuit 2 is allowed and the audio signal 8 is supplied to a speaker 4.
|
