| 摘要 |
PURPOSE:To obtain the excellent performance of calling with ringing torelance increased by arraying microphone units at random equal intervals in a line and by arranging a speaker on the same axis with the array. CONSTITUTION:Microphone units 4-1-4-n are arrayed at intervals a half the wavelength of an acoustic wave of the maximum inuse frequency of microphone group part 3 and the number of microphone arrayed in a line is made euqivalent to the wavelength of an acoustic wave of the minimum inuse frequency. Linear fitting base 2, where microphone group part 3 and speaker part 5 are fixed, makes it possible to arrange the front surface of the speaker opening part on the axis of microphone group part 3. In order to amplify a sound from a receiving sound source over a broad range, speakers 6-1-6-8 are arranged in the circumferential direction having its axis on base 2 perpendicular to the floor and base 2 is fitted with transmitter 7, dial 8 and belt 9. |
