| 摘要 |
PROBLEM TO BE SOLVED: To attain improvement in sound quality when obtaining an audio output by driving a diaphragm with a magnetostriction actuator. SOLUTION: A diaphragm 106 is driven by a magnetostriction actuator 105. As a sensor, a piezoelectric element 107 is disposed between a distal end of a driving rod 153 and the diaphragm 106. The piezoelectric element 107 detects vibration of the diaphragm 106 and outputs a vibration detecting signal. The vibration detecting signal contains information of distortion that occurs in the actuator 105, the diaphragm 106 and the like. An equalizer 102, a subtractor 103, a phase correction circuit 108 and a low-pass filter 109 constitute a correction section. The correction section performs feedback correction upon an audio signal from a signal source 101 based on the vibration detecting signal. The corrected audio signal can correct the distortion that occurs in the actuator 105, the diaphragm 106 and the like, so that the vibration of the diaphragm 106 highly accurately complies with a waveform of the audio signal outputted from the signal source 101, thereby attaining improvement in the sound quality of output audio. COPYRIGHT: (C)2007,JPO&INPIT
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