| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent an erroneous detection of a key existing out of a specific space by preventing an un-detection of the key which is left behind inside the specific space. <P>SOLUTION: A detector 10 includes a control section 14 which controls a first detection signal SG1, a second detection signal SG2 transmitted into a specific space 2 by a first antenna 11 and an interference signal SGD transmitted by a second antenna 12, and a discrimination section 15 for discriminating an existent position of an electric wave transmitter/acceptor 20 based on a response signal received by a third antenna 13 which receives a response signal SGR transmitted to the received first detection signal SG1 and second detection signal SG2 by the electric wave transmitter/acceptor 20. The control section 14 controls so that the second detection signal SG2 and the interference signal SGD negating the second detection signal SG2 are both simultaneously transmitted when such a state is detected that the specific space 2 becomes a closed space, and the discrimination section 15 discriminates that the electric wave transmitter/acceptor 20 exists in the specific space 2 when the response signal SGR is received by the third antenna 13. <P>COPYRIGHT: (C)2012,JPO&INPIT |
