| 摘要 |
<P>PROBLEM TO BE SOLVED: To detect a disconnection and/or a short circuit of a speaker 2. <P>SOLUTION: A vehicular travel notification sound generation device 1 has a speaker 2. A signal of vehicular travel notification sound is amplified by a power amplification circuit 6 and supplied to the speaker 2 via a coupling capacitor 5. A voice coil of the speaker 2 retards a phase of voltage Vp appearing on a terminal of the speaker 2. The voltage Vp has retardation in phase with respect to voltage Vs when the speaker 2 is normal and has a synchronized phase with the voltage Vs when the speaker 2 has disconnection. A disconnection determination section 542 determines the disconnection of the speaker 2 on the basis of the phase difference between the voltage Vp and the voltage Vs. A control device 7 activates a warning device 11. A short circuit determination section 543 determines a short circuit of the speaker 2 if a variation in the voltage Vp falls below a threshold while the signal of the vehicular travel notification sound is supplied. <P>COPYRIGHT: (C)2013,JPO&INPIT |
