| 摘要 |
PURPOSE:To prevent deterioration of sensitivity and to suppress the production of noise due to external disturbance, by a method wherein a receiver body is covered in a sealed manner with a sound wave permeable rectifying cover, and the inside is filled with water or liquid being approximately equal to a proper acoustic resistance. CONSTITUTION:An acoustic receiver body 1 is covered in a sealed manner with a rectifying cover 6 having a permeability-against sound wave, and is supported by means of elastic substance 7. The rectifying cover 6 is formed in the shape having less resistance against a water current, and the inside is filled with a liquid 8. A liquid, such as water, having a proper acoustic resistance equal to that of an environment wherein the receiver is installed, is used as the liquid 8. A setting leg 10 is formed at the lower part of the rectifying cover 6. If a sound wave reaches, it passes through the rectifying cover 6 to reach the acoustic receiving body 1 after it propagates in the liquid 8. A moving outer casing 2 of the acoustic receiver body 1 vibrates following the sound wave, and vibrates a moving coil 3. In case the vibrating direction of the coil 3 crosses a direction of lines of magnetic force, produced by a weight substance 4 at right angles, an electric signal corresponding to the sound wave is obtained. |
