| 摘要 |
<p>PURPOSE:To expand the effective range of the title device without increasing the transmitting power by scanning the main oriented direction of electromagnetic waves radiated from a questioning device within a prescribed angle range at a prescribed speed. CONSTITUTION:Electromagnetic waves from a questioning device 2 provided with an antenna 3 are received by means of a responder 18 mounted on a vehicle 17 which is an object to be identified and a specific code stored in the responder 18 is read out after the responder 18 is actuated by means of the electromagnetic waves. At the same time, the electromagnetic waves are sent after the waves are modulated by means of the code. When the device 2 transmits the electromagnetic waves, the rotation of a motor 5 is transmitted to the device 2 through a gear box 6 and the device 2 is rotated. As the antenna 3 is rotated around an antenna shaft 11, the main oriented direction of the electromagnetic waves radiated from the antenna 3 changes and the main oriented direction is scanned. Because of a power cable 7 between the frame 1 of a stationary section and device 2, the rotating extent of the device 2 is limited to a prescribed angle range and the reversible rotation of the motor 5 corresponding to the reciprocating motion of the device 2 within the angle range is controlled by means of a motor control circuit 9.</p> |
