| 摘要 |
PURPOSE: To realize a multi-function audio device that stands shock and vibration and can simultaneously excite a low frequency signal and a high frequency signal. CONSTITUTION: In the multi-function audio device comprising a sounder 100, a rotor 200 and a stator 300, a system block of a drive circuit comprises an oscillator 21, a frequency divider 22, a drive circuit 23, a voltage detection circuit 24, a comparator 25, a sweep circuit 26, a hold circuit 27, and a counter 28 or the like to detect a different between voltage produced in a stator winding 306 at rotation state and stop state of the rotor 200 so as to restore to the drive by a start frequency at slow-up start.
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