| 摘要 |
PURPOSE:To surely detect a medium defect by fetching only an index synchronizing component from a piezoelectric element AE signal, and executing a floatation evaluation by this index synchronizing component. CONSTITUTION:The titled system is provided with a slicing means 4 for slicing a self-oscillating signal fetched from an AE element by a prescribed slice level, a synchronizing means 5 for allowing a prescribed signal wave component sliced by the slicing means 4 to synchronize with a sector signal (3), a storing means 6 for storing an output from the synchronizing means 5, and an evaluation processing means 7 for bringing an output of the storing means 6 to OR, and executing an evaluation of a disk medium from its OR output information. This system is constituted so as to execute a floatation evaluation test for deciding whether a defect of the disk medium exists or not by a signal obtained by separating an index synchronizing component synchronizing with an index signal (2) from an AE signal (1) by an evaluation processing means 7, and bringing the index synchronizing component of an (n) round portion to OR by the evaluation processing means 7. In such a way, a medium defect can be detected surely.
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