Research On Feed-forward Active Noise Control With Virtual Instrument Approach

With the development of our society raise a serious topic, which illustrate that noise disturbance has been a serious problem. There exists a great value in military and civilian use of how to minimize and cancel the noise. Active noise control is a hot spot in recent years of research. It overcomes the drawbacks of passive noise control, such as large, bulky, costly, and ineffective at low frequencies. This technology has shown a great value of application.Based on the adaptive filtering theory, this thesis shows a detail research of the principle of active noise control and its fundamental algorithms. Various algorithms of active noise control have been developed using the tool of LabVIEW, which is the most successful tool in virtual instrument, for the first time in China, and for the purpose of simulation and further research.Algorithm of FX-LMS and its performance are shown in this thesis. Furthermore, new modified algorithms have been developed to improve the performance of FX-LMS. Also, single channel active noise control is extended to muti-channels. FX-LMS algorithm for two channels is deduced and implemented using LabVIEW. Moreover, using the tool of wavelet analysis, a very useful tool for signal processing; combine this tool with adaptive filter theory to make active noise control more effective.Usually, a quiet zone only exists at the error sensor. Due to this shortcoming, virtual sensor theory is introduced into active noise control. Finally, a few issues of the implementation of active noise control using LabVIEW are analyzed. Some proof experiments are carried and good results are obtained.