| 摘要 |
PURPOSE:To obtain the most proper amplification degree even when the level of AE signal differs by cutting conditons by reading successively AE signals during the prescribed learning time T and by calculating the amplification rate based on the mean value of the read AE signals thereof. CONSTITUTION:When a motion is started, the AE signals given via AE sensor 3, amplifier 4, band-pass filter 6 are successively read during the prescribed learning time T. The average process of the inputted AE signals in which the readings are taken is then performed and the amplification rate of the amplifier 4 is calculated based on the mean value thereof. The feed back value of an amplification rate setter 5 is adjusted via an interface 14 so as to get to the amplification rate thus calculated. The AE signals due to a chip and friction, etc. become close to the standard level nearly if the amplification rate is adjusted in order that the mean value of AE signals obtainable at the usual cutting time becomes on the standard AE signal level. |
