Active Noise Reduction System For Seats In High-speed Train Sightseeing Area

As the speed of high-speed trains increases,the noise problem gradually increases,which undoubtedly has a great impact on passengers' comfort.Nowadays,many solutions to the noise problems of high-speed railways are passive noise reduction measures,such as: installing sound barriers on both sides of the railway,adding sound-absorbing materials to the car body plates,and adding vibration damping facilities to certain components.However,in practical applications,it is found that these methods have good blocking and elimination effects on high-frequency noise,but are less effective on lowand intermediate-frequency sounds.However,after testing inside the train,it is found that the noise frequency band is mainly concentrated between 100 and 1000 Hz.The active muffler technology of low and medium frequency sound gradually entered the researchers' vision.Nowadays,more active noise reduction technologies are based on adaptive algorithms.After long-term development of adaptive algorithms,the Fx LMS algorithm that takes into account the secondary path transfer function is mostly used.This paper aims at the performance of the algorithm.The key part of the secondary channel modeling with greater influence is studied,and the two main methods of secondary channel modeling are simulated and analyzed.By comparing the noise reduction effects of different types of sound source signals,the suitable for the experiment in this paper is selected.Modeling methods.According to the simulation results and the actual situation in the laboratory,the offline modeling method is selected as the secondary pathway modeling method in this paper.Using the DSP and CCS software to complete the hardware and software design of the active noise reduction system,combined with the existing equipment and equipment in the laboratory,the experimental model was built in the semi-anechoic room,and the verification experiment was carried out.In the experiment process,the experiment plan of single noise sources at different positions was first used to verify the noise reduction function of the built system for single frequency sound signals of different frequencies.The experimental results show that the system has achieved a single frequency sound of 300 ? 700 Hz with 3.8-11.4d BA noise reduction effect.Through the single sound source experiment,some problems in the existing system are found,and the system problems are optimized and verified by simulation.The simulation results show that the error signal of single frequency sound can converge to 0,and the white noise The signal amplitude of the pink noise is reduced by about 97%,and the optimized system has achieved certain noise reduction results for single-frequency sound and white noise.