| 摘要 |
PURPOSE: To obtain the sonic pressure of a standard impact wave with at least a specified bar with a simple and rigid constitution, by separating a medium which propagates sound with a sheet from a measuring chamber, filling the measuring chamber with a gas having an acoustic impedance lower than an acoustic propagating medium and detecting displacement of the sheet with an optical means. CONSTITUTION: A sheet 2 having a thickness of 1μm-100μm is mounted on a casing wherein one surface 20 is in contact with an acoustic delivering medium 3. The casing 13 surrounds a measuring chamber 4. The measuring chamber 4 is filled with a gaseous substance having an acoustic impedance lower than that of the medium 3. The other surface 21 of the sheet 2 in the same side as the measuring chamber is formed by a reflector area 22 which is at least partly reflective optically. Furthermore, an optic fiber bundle 50 is arranged opposed to the reflector area 22 of the sheet in the measuring chamber 4. And, displacement of sheet 2 and the reflector area 22 is recorded as changes of intensity in the reflected optical signals in an evaluating unit 10 connected to the optical fiber bundle 50.
|
