| 摘要 |
PURPOSE:To decide the abnormality of a tool, by simultaneously generating both the output of a divider, to which a signal after full-wave rectification is input, and the output of rapid change abnormality of an AE level obtained by inputting a signal of averaged level after a leveling processing circuit to a rise up part. CONSTITUTION:An AE signal detected by a sensor 1 is amplified by a preamplifier 2 and fed to a rise up abnormality detecting part I of AE level and a frequency abnormality detecting part II. In the detecting part I , extracting an averaged level of the AE signal through a full-wave rectifying circuit 3 and a leveling processing circuit 4 and detecting a rapid change of the averaged level in a rise up detecting part 13, a signal of rise up abnormality is output from a comparator 9. While in the detecting part II, a divider 8, in which the ratio Y/X of the whole frequency component X to a necessary frequency component Y taken out from a band pass filter 6 is input to a comparator 10, outputs a signal of frequency abnormality from the comparator 10 when said ratio exceeds the preset threshold level. |
