In real environment, the interference rejection of the generalized sidelobe canceller (GSC) microphone array with adaptive blocking matrix (ABM) will be deteriorated by mistracking of target, which may be caused by either steering error or misdetection of adaptation mode control. As a remediation, the tap coefficients of the ABM filters are constrained to leak the interference into the sidelobe canceling path. One inherent problem of the conventional ABM structure is the incoherent spread of filter coefficients for different signal frequency, which will lead to insufficient suppression of low frequency interference in the case of mistracking. This paper proposes an enhanced frequency-domain GSC with a new pulse-width constrained ABM, in which the spread of filter coefficients is less sensitive to signal spectrum, to improve the interference rejection against mistracking. Experiment in real environment shows that the loss of interference rejection caused by mistracking is reduced from 6.31dB to 1.06dB.
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