| 摘要 |
PURPOSE:To provide the directivity of sharp doughnut shape through ease of adjustment with a comparatively small size having less number of sound receiving elements in use. CONSTITUTION:Output signals from three sound receiving elements 11, 12, 13 arranged on a line at an equal interval are delayed by delay circuits 14, 15, 16 whose delay times are respectively tau1, tau2, tau3. An output signal from the sound receiving element 12 arranged in the middle of the three sound receiving elements 11, 12, 13 and a signal delaying the said output signal by a time (tau1+tau2) are synthesized in phase (that is, addition) and signals delaying output signals from the sound receiving elements 11, 13 by times tau1, tau2 respectively are synthesized in opposite phase (that is, subtraction) in a synthesis section 17. |
