Noise Source Identification Analysis Of Limited Space

With the rapid development of the society and higher requirement for the environmental noise, the vibration and noise of mechanical equipment would become an important index to check its function gradually. To reduce the noise of mechanical equipment the accurate measurement and analysis of noise also the identification of the main noise source are necessary. Then some structural improvement or noise control could be made. There is reflection interference in limited space and the reflection is a kind of serious interference to sound source identification. Obviously the result of the sound source identification in limited space must be modified or eliminated directly on the reflection interference.There are simulation and experiment parts carried out to observe the effect of complex cepsturm under the conditions of different acoustic signal type,different frequency and different reflecting distances etc. And good results were got which are close to the results got in anechoic chamber. It is indicated for simulation and experiment results and also error analysis that first, there is an advantage of complex cepstrum in dealing with fast decay acoustical signal; second, if the acoustical signal frequency is within 5500Hz range, the effect of results will increase with frequency; thirdly when the delay distance of the reflection is as short as 92cm, a good result is still could be got but to 50cm the result is negative. The effect of reflection eliminating relies heavily on recognizing the peak of reflection in complex cepstrum domain and the filtering effect.Finally the paper based on a cone loudspeaker with a combination of complex cepsturm and microphone array would be used to eliminate the reflection and reconstruct the sound field. In the end an accurate effect of the identification through the sound without reflection would be got. In general, the method of complex cepstrum combined with microphone array is feasible and effective.