| 摘要 |
PURPOSE: A system and a method for imaging narrow-band noise, system and method for monitoring the state of a transport machine using the system and method are provided to visualize a moving noise source generating narrow-band noise and to monitor the state of the transport machine in real time in a noncontact state. CONSTITUTION: A narrow-band noise imaging system includes bottom and side microphone arrays(1,3), a reference microphone(4), and a signal processor(8). The microphone arrays measure a sound pressure of narrow-band noise that is emitted from a transport machine. The reference microphone is attached to the transport machine to measure the spectrum of the entire band of the narrow-band noise and the spectrum of the center frequency of the noise. The signal processor calculates the ratio of the spectrum of the entire band to the spectrum of the center frequency and divides the sound pressure measured by the microphone arrays by a sound pressure according to the ratio to obtain noise hologram so as to image the noise. |
