Reference Signal Reshaping In Active Noise Control Based On Generalized Sidelobe Canceller

Compared with the traditional passive noise control,active noise control has stronger adaptability and low-frequency noise control ability,it is becoming more and more important.When the active noise control system controls the target noise,the reference microphone is easily disturbed by other environmental sound sources,which may reduce the correlation between the reference signal and the target noise.It then causes the secondary sound source to emit waves whose frequency components are related to the ambient sound source,which attenuates the ambient sound in the sound field.In this paper,a reference signal reconstruction method based on GSC is proposed.The target noise signal in the sound field is extracted by spatial filtering and the ambient sound source signal is suppressed,which improves the correlation between the reference signal and the target noise and reduces the attenuation of the ambient sound caused by the active noise system.Starting from the transfer function of ANC system,this paper demonstrates the influence of the correlation between reference signal and target noise,simulates and discusses the influence of parameters in NFx LMS and Fx RLS algorithms,and provides suggestions for the selection of parameter values.By introducing the ambient sound into the reference signal as interference,the noise control is simulated.The results show that the interference in the reference signal will cause attenuation of the ambient sound in the sound field,and it also proves the importance of the reshaping of reference signal.The algorithm principle and improved method of generalized sidelobe canceller(GSC)are discussed.The effects of signal-to-interference ratio(-10 to 10 d B)and convergence factor on sound extraction of improved GSC are studied with simulation,and compared with other algorithms.The results show that the improved GSC can obviously suppress the interference sound source signal in the sound field,and causes little influence on the acquisition of the target sound,and it has strong stability.In the sound field of target noise signal and ambient sound signal,the target noise is extracted by GSC,and the influence of power change and positions of sound source on GSC is discussed.It is proved that GSC is robust to the variation of sound power change,and when the difference of DOA between sound sources is about 15 degrees,it will not affect the extraction of target signals.Taking the output of GSC as the reference signal after remodeling,the noise control of ANC system is simulated.The results show that the application of GSC can obviously reduce the suppression of ambient sound caused by ANC system.With Fx RLS algorithm,the attenuation of ambient sound is reduced from 13.88 d B to 0.07 d B,while the reduction of target noise can be maintained.Finally,in the control of the sound sources with crossed frequency range,the subjective evaluation of control results,shows that GSC can control the target noise while maintaining the hearing sense of ambient sound.