Implementation Of Narrowband Active Noise Control System Based On DM642

Noise pollution has become more and more serious in today’s life, affecting people’s normal life and production. Lots of noise is generated by rotating equipment, such as pipe fans, car engines, propeller and so on. And these are main ly low frequency noise, the traditional passive noise control technology is difficult to solve it. Therefore, active noise control(ANC) is proposed, which is very suitable for the control of narrow-band low-frequency noise. Narrow-band low-frequency noise research on noise reduction techniques need to start from the theoretical and experimental. Theoretical research has been relatively mature, and in recent years, many ANC algorithms have been proposed and simulated by computer. However, limited to the development of electronic hardware technology, practical application is not ideal. In this paper, the FXLMS adaptive filtering algorithm is used as the main algorithm of ANC technology, and the hardware implementation of ANC system based on TMS320DM642 is studied. The main research work is as follows:Firstly, the theoretical knowledge of ANC technology is studied, including the theory of pipeline sound field-analysis of the noise elimination principle of the pipeline, adaptive filtering theory, comparison of three types of controllers, and adaptive filtering algorithm. After analysis and comparison, select the appropriate controller type. At last, analyzes the implementation process of the active noise control algorithm-FXLMS algorithm which is used in this paper, and to simulate the algorithm by computer.Secondly, give the overall design of ANC controller, the hardware theory of TMS320DM642 as ANC controller is studied in detail, analyze its a dvantages as the ANC controller and design the basic system of ANC controller; The specific characteristics, communication protocol and application method of Mc ASP and audio chip TLV320AIC23 B are studied. For the latter research needs, the design of the multi-channel noise acquisition circuit board is completed.Thirdly, complete the ANC system software program based on TMS320DM642. First, the development process of ANC software is introduced, and the program block diagram of the algorithm is given. Simulation and comparison of FXLMS algorithm for online and offline identification of secondary channel, illustrate its application scenarios, advantages and disadvantages. To build a pipeline platform and write primary noise generation and error noise monitoring program.Fourthly, to complete the narrow pipeline noise reduction experiment when DSP is only responsible for the elimination of noise, including single frequency, multi frequency noise reduction experiment. Analyze the results, point out the problems and solutions in the experiment, and puts forward the new requirem ents for the follow-up study.