| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To perform high-sensitivity and high-speed communication through a radio monitoring system between a monitor device and a plurality of camera devices by an inexpensive structure. <P>SOLUTION: In a communication standby mode, a narrow-band filter 35a is used and while the directivity direction of a phased array antenna 30 is changed with time, a communication permission request signal is expected to be transmitted from camera devices 2. When a communication permission request signal transmitted from one of camera devices 2 is received, the narrow-band filter is switched to a wide-band filter 35b, and the directivity direction of the phased array antenna 30 is fixed to perform high-speed communication. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
