Critical Analysis of the Eigenfilter Method for the Design of FIR Filters and Wideband Beamformers

摘要

The least squares based eigenfilter method has beenudapplied to the design of both finite impulse response (FIR) filtersudand wideband beamformers successfully. It involves calculatingudthe resultant filter coefficients as the eigenvector of an appropriateudHermitian matrix, and offers lower complexity and lessudcomputation time with better numerical stability as comparedudto the standard least squares method. In this paper, we revisitudthe method and critically analyze the eigenfilter approach byudrevealing a serious performance issue in the passband of the designedudFIR filter and the mainlobe of the wideband beamformer,udwhich occurs due to a formulation problem. A solution is thenudproposed to mitigate this issue, and design examples for both FIRudfilters and wideband beamformers are provided to demonstrateudthe effectiveness of the proposed method.