Implementation of Active Noise Control on the Headphone
Date Issued
2008
Date
2008
Author(s)
Chen, Zhi-Huang
Abstract
It is to utilize FIR (Finite Impulse Response) Digital filter as the main structure of the control system for this thesis,and meanwhile use LMS (Least Mean Square ) to modifyn real time weighting coefficient of the algorithm to feedback the digital filter for trying to get the best control effectiveness. As regard to the experiment, the frequencies under controlre all below 600Hz and the adapatively active control of acoustic sources .including these ones for mono,dual,and white noise sources on the sound reduction to be controlled.The experiment of the study is firstly to try to attenuate the sound at the unilateral headphone,the result of noise reduction by 10~20dB for mono,dual,and white noises are obtained . Then,we continue to set up the active attenuation on the bilateral headphone.Due to the different travel times for sound waves to arrive the right and the left ears,the sound pressures measured at the associated microphones,and so did the resulting noise reductions.Therefore,the distinction of controll effectiveness by 5~8dB between two ears is obtained.
Subjects
adaptive control
Type
thesis
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