| 摘要 |
PURPOSE:To measure an acoustic characteristic on the spherical surface by simple constitution and by an easy operation, by providing a microphone directed to a reference point, so that it can be moved along a single circular arc arm, and displacing an angle of the arm. CONSTITUTION:An arm 12 has a guide groove in the circumferential direction, and to both its ends, a pulley 15 and a pulley 16 are installed. To a cable 37 stretched between the pulleys 15, 16, a holding body 18 for holding a microphone 17 is connected. The microphone 17 is directed to a reference point 6. The holding body 18 is supported by a guide piece for prescribing the guide groove, and allows the microphone 17 to run by 1/4 circular arc centering around the reference point 6. The pulley 15 is driven and rotated by a motor 21. As a result, the arm 12, and following it, the microphone 17 is displaced as to its angle round the axis on a virtual straight line 13, and also a position where the microphone 17 goes along the arm 12 can be set by driving the motor 21. |
