| 摘要 |
PURPOSE:To remove the peak by the components of the background noise appearing in histogram by synchronizing the threshold value of a comparator to rotating angles in a hystogram device. CONSTITUTION:The acoustic signal (d) to be monitored sampled from a rotating machine is inputted to A of a comparator 1. The control of a switching circuit 2 provided for the purpose of taking in the envelope signal of the normal time is accomplished in a histogram processing part 4, and the results thereof are stored in a temporary storage device 3. The background noise which has been stored in the device 3 and is added with constant bias by a bias device 5 is outputted to a terminal A' of the comparator 1 to determine the threshold level of the comparator 1. The comparator output (e) obtained in this way is used in a histogram processing part 4. The results of the output of the resultant histogram is judged by the operator for the presence or absence of any abnormality. |
