| 摘要 |
PURPOSE:To obtain the result of reproduction of a sound source of a body under test having a high S/N ratio, by performing wind processing of a hologram, and reproducing the sound source. CONSTITUTION:A body under test 01, which generates noises, is located approximately in a plane of (u)-(v). A recording plane 02 is located in a plane (x)-(y) at a position, which is separated from the body under test 01 by a distance (z). Signals from a scanning microphone 03, which can be moved in the longitudinal and lateral directions, and from a fixed microphone 04 are converted into Fourier spectrums by an FET device 06. Cross power spectrums 07 are computed. The complex amplitude distribution of the sound pressure for each frequency in the recording plane 02 is obtained. When sound source data is reproduced based on a hologoram 08 with the frequency component of the body under test as a parameter, the following procedure is carried out. The hologram undergoes Fourier transformation. Wind processing is performed by a wind function (a). Division is performed in a wave-number space plane by using a transfer function (b). The result undergoes reverse Fourier transformation. Then the sound data is outputted. |
