| 摘要 |
PURPOSE:To detect abnormality of material accurately, by detecting a Barkhausen noise generated with the magnetization of a ferromagnetic body to weight Barkhausen noises different in the level. CONSTITUTION:A counter 6 counts the number of input signals in terms of the intensity range i (i=1,2... and n) previously classified once converted into digital from analog and outputs counts for respective ranges into an arithmetic unit 7 separately. The arithmetic unit 7 adds up all of the input signals with an addition circuit 73 into which counts Ni (i=1,2... and n) of respective ranges (i) in the counter 6 are inputted to determine the sum SIGMANi of Barkhausen noises and multiply H1<m>, H2<m>, H3<m> ... and Hn<m> obtained by rasing the center values of the respective ranges by input signals N1, N2 ... and Nn by the ranges to calculate the sum SIGMA(NixNi<m>). The SIGMA(NixHi<m>) is weighted so that a larger value will be given for the organization having more crystals with the larger particle diameter. When abnormality is detected based on the indicator, an alarm is given thereby enabling accurate detection of abnormality in the material. |
