| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem in which a Patent Document 1 discloses that, for extracting a weak eddy current signal from an inside of an inspected body contained in a detection signal of a detection coil, a giant eddy current from a surface layer part is cancelled by a sinusoidal signal with an adjusted amplitude and phase; however, according to a method illustrated in an embodiment, a masking signal is cancelled by adding a signal with a manually adjusted amplitude and phase of a signal exciting an excitation coil to the detection signal, and a manual operation exists, resulting in obstruction of an automatic measurement.SOLUTION: An electromagnetic induction inspection device is configured to prepare: a first DA converter that supplies a driving alternate current signal to a driving coil; and an AD converter that converts a sum signal of an output signal of a detection coil and an output of a second DA converter. The electromagnetic induction inspection device causes the first DA converter to output the driving alternate current signal periodically and causes a signal reversing polarity of an alternate current collected by the second DA converter in a state of the second DA converter being stopped to be output from the second AD converter in synchronization with a period upon collection. Thereby, a signal cancellation of a front layer part described in the Patent Document 1 is automatically achieved. |
