| 摘要 |
PROBLEM TO BE SOLVED: To assure a sufficient volume with the fixed directivity in a high band when music sound or voice is amplified while imparting the directivity. SOLUTION: In a speaker array comprising a plurality of speakers arranged linearly, and a one-dimensional digital filter provided for each speaker and delivering an inputted sound signal to a corresponding speaker while filtering, each one-dimensional digital filter is set with a filter coefficient having (a) a wider pass band in the direction of standardized space frequency for higher standardized time frequency and (b) increasing the amount of phase rotation as the end of pass band is approached or the standardized time frequency increases on a cross-section of fixed standardized time frequency when the frequency characteristics of a two-dimensional digital filter formed of each one-dimensional digital filter are represented on the two-dimensional frequency plane. COPYRIGHT: (C)2009,JPO&INPIT
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