Bandpass MFD polynomials with wideband constant delay characteristic and wave-front synthesis using them

摘要

For the purpose of the sound image control by using a liner array of loudspeakers and 2-D digital filter, a method of the wave-front synthesis using 1-D bandpass MFD polynomials which has wider delay band than that of lowpass MFD polynomials is proposed. In order to obtain the extreme wideband delay of MFD polynomials with the negative τ{sub}0, an adequate selection of the eigenvalue of the polynomial and the center frequency of the band is investigated. In this paper, 1-D filter sections are constructed by a cascade of IIR all pass filters, in which the MFD polynomials are used, and a term of integer units delay. The wave-front synthesis can be completed by spatial windowing including compensation of distance attenuation for resulting 2-D filter outputs.