Aiming at the problem that the amplitude frequency characteristic andthe group delay characteristic of the traditional fractional delay filterdeteriorate at the higher frequency, a fractional delay filter based onHermite interpolation polynomial is proposed to approximate the idealnon-integer delay filter system. This filter improves the energyspectrum of sonar beamforming, and allows the system to avoid usinghigh sampling rates to improve delay accuracy, which helps to reducecomputer storage performance requirements. By comparing thefrequency response characteristics of the Least-squares linear-phaseFIR filter, Lagrange and Hermite fractional delay filter with same order,the Hermite fractional delay filter is proved to be less attenuated andless error at the high frequency.
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