专利名称：Device for the activation of an apparatus for
measuring acoustic emission by detection ofbackground noise
发明人：Bernard Audenard,Jean Marini申请号：US06/280355申请日：19810706公开号：US04423634A公开日：19840103
摘要：An apparatus for measuring acoustic emission is activated only at critical periodswhich are determined by detection of the background noise from a reference level. Anacoustic emission transducer continuously transmits a signal to a detection circuit whichdelivers the top modulation envelope of the background noise to a comparator at areference level delivered by a control unit.
When a mean level of the background noise does not exceed a threshold referencelevel the AE is sampled at a low rate, f. When the background noise exceeds thethreshold reference level the data sampling unit is activated to sample AE at a muchhigher rate F. Therefore AE is sampled at a high rate only when the pump or othermachine under test is running and at a low rate when the article under test is notoperating. The AE testing device also includes a frequency spectrum correlator whichallows background noise to activate the increased sampling rate only if the noise is in agiven frequency range.
申请人：CGR
代理机构：Cushman, Darby & Cushman
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