| 摘要 |
PURPOSE:To estimate the depth of a flaw, by a method wherein a wide-band surface wave is used to be propagated through the surface of an object to be inspected and frequency analysis is applied to the reflected signal from the flaw. CONSTITUTION:The titled apparatus has a wide-band surface wave sensor 20 for propagating a wide-band surface wave through the surface of an object 21 to be inspected, a pulse generation circuit 1 for applying a pulse to the sensor 20, the gate circuit 3 connected to the sensor 20 and taking out only the reflected signal from the flaw directly under the surface of the object 21 to be inspected and an amplifying circuit 2 and constituted so that said reflected signal is analyzed by a frequency analytical circuit 4 and displayed on a display apparatus 5. By this constitution, a high frequency component vibrates only the vicinity of the surface 11 corresponding to the depth of the flaw 10 when a wide range of a frequency component is emitted from the circuit 1 and, therefore, said frequency component escapes through the space between the flaw 10 and the surface 11 without being reflected by the flaw 10 while, because a part of a low frequency component is reflected from the flaw 10 and returned, the depth of the flow 10 can be estimated by performing frequency analysis. |
