A study of the analogue compensating monopole system for active attenuation of noise in a duct

✍ Scribed by Jiluo Zhou; Tielin Shi

• Publisher: Elsevier Science
• Year: 1989
• Tongue: English
• Weight: 680 KB
• Volume: 28
• Category: Article
• ISSN: 0003-682X
• DOI: 10.1016/0003-682x(89)90093-5

✦ Synopsis

This paper describes theoretically the feedback effect of the secondary source on the primary source in a monopole system for active attenuation of noise in a duct, and gives a more accurate mathematical model Based on the model mentioned above, a new monopole system called the Analogue Compensating Monopole System, or ACM-System for short, is established. An analogue method .for compensating the non-ideal phase response of the system is suggested and discussed, and measuresJor improving the non-ideal amplitude response are proposed. In order to improve the working stability of the system, a directional sound detector is introduced, and the absolute stability condition of the A CM-System is given. Test results show that the method for compensating for the phase errors and improving the amplitude characteristics of the system is effective. Experimental data from the A CM-System in conditions of.flowing and quiet air in the duct are processed. Test results show that the ACM-System has a noise reduction ability superior to that of other monopole systems, whether in narrow or wider frequency bandwidths.