Design Of Indoor Active Noise Reduction Control System

With the acceleration of China’s modernization process and the development of economic construction year by year,it has also brought about indoor noise pollution problems in people’s living environments.With the increasing strictness of relevant laws and regulations and the increasing demand for indoor environmental quality,how to effectively improve the acoustic environment has become an urgent problem to be solved.In real life,most cases use passive noise reduction technology for noise control based on the propagation path of noise.However,the method of passive noise reduction has certain limitations,and its suppression effect on low-frequency noise generated in daily life is not significant.And such problems can be strengthened through Active Noise Control(ANC)technology,which has significant effects on low-frequency noise control and outstanding characteristics,with strong customizability and high integration.Therefore,this thesis aims to reduce the low-frequency broadband noise received in indoor environments,and focuses on researching active noise reduction control systems suitable for eliminating external noise in indoor environments.The main work of this thesis is as follows:Firstly,this civilization has established the research background of active noise reduction technology and conducted research on the current research status of active noise reduction technology both domestically and internationally.The basic theories of acoustics and control involved in the research have been derived and analyzed,providing theoretical support for active noise reduction technology;Then,starting from the application scenarios of high-rise indoor environments,design the overall function of the active noise reduction control system and formulate the main system indicators;Furthermore,the typical indoor noise signals of high-rise buildings are collected and their characteristics are analyzed.It is concluded that the indoor noise is mainly low-frequency broadband noise of plane wave nature.Secondly,design the structure of the active noise reduction control system,analyze the active noise control structures of feedforward,feedback,multi-channel,single channel,broadband and narrowband,and design the feedforward single channel broadband active noise reduction control structure that best matches the noise reduction target.Build a feedforward single channel broadband active noise reduction control system model based on adaptive filters,and conduct simulation experiments,The noise reduction effect of the simulation experiment is about 20 d B,verifying the theoretical feasibility and reliability of the system.Subsequently,the various modules of the active noise reduction control system model,including the acoustic signal acquisition module,signal communication module,signal processing module,and acoustic signal output module,were carefully demonstrated,designed,and implemented under the guidance of system reference indicators.Finally,the overall noise reduction effect of the system is demonstrated through experimental means,and active noise reduction experiments are conducted on noise with different frequency characteristics;Based on the built active noise reduction platform,the active noise control test is carried out for the single frequency noise signal,mixed frequency noise signal and common real noise signal under the indoor environment of high-rise buildings simulated by plane wave speakers.The experimental results show that within a certain area,the indoor active noise reduction control system designed in this thesis has a certain inhibitory effect on low-frequency broadband noise;The noise reduction effect on single frequency noise is about 12 d B,the noise reduction effect on mixed frequency noise is about 6d B,and the noise reduction effect on recorded real environment noise is about 5d B.The experimental results indicate that the system has certain practical value in improving the indoor sound field environment.