A New Frequency-Domain Adaptive Blocking Matrix Design for Generalized Sidelobe Cancellation
Qinyun Yang, Yi Zhou, Yongbao Ma, Hongqing Liu · 2020
The generalized sidelobe cancellation (GSC) is widely used in microphone array speech enhancement Due to the inaccurate estimation of the time delay and misjudgment of the adaptive mode control (AMC) module, the performance of the fixed beamformer (FBF) and the adaptive blocking matrix (ABM) are not satisfactory, especially when the ABM fails to completely block the desire signal, which causes the desire signal be eliminated in the adaptive noise cancellation (ANC) module. Moreover, the conventional ABM with coefficient-constrained adaptive filters (CCAFs) will cause the tracking range changes with frequency. In this paper, a new frequency-domain ABM is proposed which utilizes the voice activity detection based multiple main lobes (VAD-MML) method to control its coefficients update. By comparing the energy of each frame after beamforming in the desired direction with the maximum at other directions, the frame-level adaptive control factor can be obtained. The simulation results demonstrate the proposed approach can better reduce the leakage of the desire signal and the loss of interference rejection.