The Study Of Active Noise Control System In Duct Based On TMS320VC5509A

Along with the large equipments are widely used in industry, noise pollution has been a popular issue in environmental protection all over the world. ANC is especially suitable for reducing low frequency noise which is difficult to achieve for traditional method. ANC is a multi-interdisciplinary subject in which the complexity and instability of system implementation exists. Acoustic feedback is the important factor to affect system performance. Effective measures should be taken to solve problem, otherwise the adverse effect is inevitable.In this paper, the main research work is focus on active noise control applied in duct system. First of all, the pipe system is modeled and FXLMS algorithms are analyzed based on the system model. Secondly, secondary path identification methods are introduced. Finally, acoustic feedback and the neutralization algorithm used to solve the problem of acoustic feedback are discussed. The main factors that affect the performance of the algorithms including the number of filter weights and convergence step-size are especially discussed. The convergence speed and stable error are also compared and investigated.Experimental study of active noise control in duct is explored based upon the former study and simulation. The high performance fixed point Digital Signal Processor (DSP) TMS3205509A produced by Texas Instruments is used in the ANC system. The software is designed using admixture programming of C language and assembly Language. Finally, the adaptive feedforward control algorithm and neutralization algorithm are implemented in the experimental facility with single-frequency noise, multi-frequency noise, band-limited white noise and sweep signal used as input signal in experiment. The experimental results show that the performance is good and neutralization algorithm takes effect in attenuating acoustic feedback. The maximum noise reduction for single-frequency is 45dB, and the noise attenuation is obvious in the frequency range from 80Hz to 500Hz for white noise.