The Adaptive Notch Filter with Controlled Null Width

—The design of the nite impulse response (FIR) adaptive notch lter with controlled null width is expressed as a derivatively contrained quadratic optimization problem. The problem is then transformed into an unconstrained one by choosing a null matrix orthogonal to the derivative constraint matrix. In this paper, wavelet lters are employed to construct the null matrix. Taking advantage of the vanishing moment property of the wavelet lters, the proposed method can govern the null width of the notch lter for eliminating the intractable iterference by adjusting the regularity of the wavelet lters.