| Summary: | 碩士 === 中原大學 === 電機工程研究所 === 102 === Nowadays, there are many commercial ANC (Active Noise Control) headphones using either digital signal processors (DSPs) as control unit to implement the Feedback FXLMS algorithm, or analog circuit by using control theory’s feedback structure to cancel the noise in active way. However, for DSP’s product, it’s much expensive than conventional passive headphone, and for analog circuit product, it doesn’t perform as well as adaptive one with narrowband noise. As a result, this paper proposed using a micro-controller unit (MCU), Cortex-M4, instead of DSP to implement the adaptive algorithm in headsets, and also designed the controller for analog ANC structure. Experimental results illustrate the digital control ANC headsets’ performance with commercial headset to verify effectiveness. For analog system, the simulation results also show its work with broadband noise. According to the experimental results, the narrowband noise can be reduced about 10~20 dB using the proposed digital ANC system based on a low-cost MCU. The attenuation of broadband noise can also be verified by computer simulation.
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