Several Key Methods Of Hybrid Active Noise Control System In Impulsive Interference Environment

The widespread application of automated mechanical systems has improved people's quality of life,but the noise introduced cannot be ignored.This type of noise generally has obvious narrow-band characteristics.Under certain conditions of half-free field,half-reverberant field and reverberant field,noise has obvious harmonic frequency and broadband characteristics.And in practical applications,such as car whistle,mechanical damage and impulse noise interference caused by construction is inevitable.What's more,in moving vehicles,airplanes and ships,the active noise control(ANC)systems are influenced by the impulsive noise.Compared with Gaussian noise,Gaussian noise mixed with impulse interference is more difficult to achieve good tracking and stable performance.Impulsive interference generally has a relatively high amplitude.Some impulsive interference such as construction noise has a certain periodicity which influence the phase tracking performance.Others whose amplitude and phase are random will have a greater impact on amplitude and phase tracking than periodic pulses.Therefore,the narrow-band active noise control with anti-periodic pulse interference(NANC),wideband active noise control(BANC)with anti-periodic pulse interference,and the anti-broad-narrowband hybrid Pulse interference wide-narrowband hybrid active noise control(HANC)system.The specific content of this article is as follows:First of all,the traditional narrow-band active noise control algorithm(NNANC)cannot adapt to background noise power changes and the interference of impulse noise,and the use of anti-impulse noise broadband algorithm to reduce narrow-band Gaussian noise will cause a large amount of calculations.Thus,a new hybrid Fx NLMS and Fx DFC structure based on filter x virtual tracking L0 norm discrete Fourier notch filter(Fx L0DFC)is proposed.By using the pulse signal compression sensing factor and Fx L0 LMS algorithm,which is more sensitive to the environment than Fx DFC algorithm,can achieve both low computational tracking in stable environment and fast tracking in impulsive noise environment.In order to further reduce the amount of steady-state operations,a filter-e discrete Fourier notch algorithm is presented to extend applications.What's more,the target broadband noise always contains impulse interference in real-life.It will affect the iterative performance of the filter.Therefore,a new adaptive post-regulation filter based on pulse detector and Gaussian kernel function filtered–x normalized least mean square algorithm(DMPFx NLMS)is proposed to improve the algorithm's tracking ability when the background noise power changes.Then,a new adaptive optimal threshold pulse signal method is combined in the DMPFx NLMS to get better anti-pulse performance.More exactly,aiming at complex half-free,field-half-reverberant,and reverberant field,the noise reduction problem of mixed Gaussian noise with impulse interference,a new hybrid system based on the feedforward structure of the residual sine substructure(HANC-SRE)is proposed to improve the tracking and narrowband line spectrum noise reduction capabilities of the HANC system.This method can effectively reduce the narrowband noise.Based on HANC-SRE,combining the Fx L0 DFC and DMPFx NLMS methods,a HANC system based on the anti-pulse interference variable step algorithm(AT-HANC)is proposed.This method has good tracking and sinusoidal noise reduction in complex noise environments.In summary,this paper also carries out real-time experiments to verify the practicability of the proposed algorithm.(1)When the target noise is a narrow-band signal with pulsed interference,the proposed hybrid Fx NLMS-Fx DFC based on Fx L0 DFC method can reach the steady-state more earlier.(2)When the broadband with impulsive noise is introduced,the proposed DMPFXNLMS algorithm has relatively the smallest error fluctuation when subjected to pulse interference.And it achieves better convergence rate when impulsive interference occurs.(3)When the target noise is mixed noise with impulse interference,the proposed HANC-SRE has better tracking and narrowband noise reduction level.And the AT-HANC can be applied in various noise reduction application.