Steering FIR notch filter adaption by initial coefficient control

Little mention is made of pitfalls or opportunities associated with initial conditions when adaptive filters are discussed, and it is nearly standard practice simply to impose zero initial conditions on the tap weights being adapted-without further ado. In the case of interference suppression in wid...

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Bibliographic Details
Main Authors: Allen, G.H., Cain, G.D., Allen, L.D., Yardim, A.
Format: Conference Proceeding
Language:English
Subjects:
Adaptive filters
Convergence
Filtering
Finite impulse response filter
IIR filters
Interference suppression
Least squares approximation
Narrowband
Wideband
Wiener filter
Online Access:Request full text
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Summary:Little mention is made of pitfalls or opportunities associated with initial conditions when adaptive filters are discussed, and it is nearly standard practice simply to impose zero initial conditions on the tap weights being adapted-without further ado. In the case of interference suppression in wideband signals by means of direct notch filtering this approach has been found inadequate to ensure convergence. However, utilizing a single non-zero initial tap value can not only bring about convergence, but also explicitly "steer" the phase condition of the resulting notch from minimum-phase to maximum-phase. It is also found that strong pattern sensitivity carries through from initial weights to final LMS filters, with zeroes lying on the z-plane unit circle being especially persistent shapers of the final notch filtering characteristics.
DOI:10.1109/MWSCAS.1995.510210