Fast Algorithm And Implementation Of Multi-channel Active Noise Control

The adaptive filtering algorithm is the precondition of the realization of the active noise control. Under many conditions, several secondary sources and error sensors are necessary to enlarge the noise reduction space and increase the noise reduction quantity. This kind of system is called a multi-channel active noise control system. However, it is found that the calculated complexity of the adaptive algorithm will be increased greatly when the number of the channel is increased, which causes serious difficulty to the real-time realization of the multi-channel active noise control system. In this thesis, three fast algorithms associated with hardware implementation are examined.Firstly, the Filtered-x LMS is studied and the convergence performances of the algorithms are analyzed, and the modeling of the secondary path in the multi-channel active noise control system is discussed.Three fast algorithms are investigated respectively which are periodic partial iterative algorithm, the stochastic partial iterative algorithm and the algorithm with strategic choice. The calculated complexity and the convergence performance of the three algorithms are discussed respectively.In order to investigate the effect of different iterative methods on the algorithm performance, the realization principle of the fast algorithms is given. The stochastic partial iterative algorithm is divided into two cases which are average distribution and normal distribution. The DSP assemble language-based fast algorithms are accried out. Computer simulations are conducted using the mentioned three fast algorithms. It is shown that under the condition of the same system parameter and partial iterative constant, the continuous partial iterative algorithm and the average distribution stochastic partial iterative algorithm have the same convergence performance, and the case of the normal distribution stochastic partial iterative algorithm is more complicated.Finally, a multi-channel active noise control system with practical primary noise and fast algorithms is built and active control is implemented. It is shown that substantial noise reduction can be achieved.