| 摘要 |
PURPOSE:To attain remarkable sound insulation effect by providing a sound insulator facing to a noise source and a sound generator to the rear of the sound insulator, detecting noise that passes through the insulator by a reception means, changing the phase of a sound signal, and offsetting the sound by moving a sound generator back and forth by using the output of said phase-changed sound. CONSTITUTION:The sound insulator B is disposed against the noise source A, and the sound generator C consisting of a ceramic piezoelectric body is provided in the rear of the insulator B, and the reception means D is disposed close to the insulator B. The phase of a sound signal detected by the means D is changed by a phase changing means E, and based on the changed phase signal, a drive means F moves the sound generator C back and forth against the insulator B. That is, the noise detected by the means D is converted to a signal in the inverse phase or approximately inverse phase by the means E, so that the noise that is transmitted through the insulator B and sound from the sound generator C interferes with each other to be offset. |
