Research On Simulation And Experiment Of Adaptive Cancelling For Underwater Active Interference

With the development of electronic technology and control theories, active noise control has become a focus in the field of noise control in recent decades. Especially, AANC (Adaptive Active Noise Control) has already turned into the most important direction of the active noise control method in the future.The self-noise of ships is the main interference of passive sonar system, which decreases the SNR at the input interface, the reduction of the ship's self-noise is of great importance. Therefore, researches on the AANC techniques are meaningful and valuable for practical application.The AANC is based on the principle that the "secondary" sound sources can be controlled by adaptive controller to cancel the "primary" sources through sound interfere. The key point of AANC system is the configuration of adaptive filters and the corresponding algorithms. In this thesis, the Filtered LMS algorithm which is useful for the practical application is introduced and influences of the main parameters to the algorithm arc studied by computer simulations. The secondary path modeling method and the characteristics of the secondary path arc analyzed in details. By selecting TMS320C6713 DSP as the hardware of the control system, this thesis studied the feed-forward adaptive active noise control (AANC) system, and then made an experiment in the underwater stimulant noise field. A DSP-based underwater active noise control experimental system is established, and C language is used in the hardware to realize the real-time active noise control based on FXLMS.