| 摘要 |
PURPOSE:To enable multi-layer analysis within a sample, by a method wherein a received wave is multiplied by a reference sine wave and a reference cosine wave separately and sine and cosine components of the received wave are taken out with a low pass filtering to extract the level of the received wave based on the components. CONSTITUTION:At a step S1, a sine wave is emitted into a sample for a specified time and the received wave thereof is detected at a step S2. At steps S3 and S5, the received wave is multiplied by reference sine and cosine waves as specified separately and the sine and cosine components thereof are taken out at steps S4 and S6 to extract the level of the received wave at a step S7. At a step S8, information on surface of discontinuity within the sample and acoustic impedance pertaining a multi-layer is obtained based on the level of the received wave to inspect the inside of the sample.
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