| 摘要 |
PROBLEM TO BE SOLVED: To surely and easily detect partial discharges of electrical equipment or abnormal noises from mechanical equipment, irrespective of the presence or absence of a barrier, also by reducing influence due to noises. SOLUTION: Noises are actively silenced by collecting abnormal sound generated from an abnormal sound detecting object by a parabola 11 and converting it into a sound signal through a microphone 12; converting this sound signal into a digital signal through an amplifier 13, a filter 14, and an A/D converter 15; performing FFT operation by a DSP 16, based on this digital signal; identifying the abnormal sound and also obtaining control sound that has the same amplitude as the periodic noises identified by the DSP and is in opposite phase therewith; converting this control sound into a sound signal by an A/D converter 17, a filter 18, and an amplifier 19; emitting it from a loudspeaker 20 toward the abnormal sound detecting object; and making the sound signal interfere with the noises existing in the periphery or the inside of the abnormal sound detecting object. COPYRIGHT: (C)2006,JPO&NCIPI
|
