| 摘要 |
<P>PROBLEM TO BE SOLVED: To accurately detect an intruder only who actually approaches a secured wall. <P>SOLUTION: A conductive panel 12 is inserted into a plate-like non-conductive structural material 11 in such a manner that its surface becomes parallel with a wall surface, thereby constructing a security fence 1. A signal generation part 26 of a signal application part 22 generates a probe signal that is a signal having a prescribed frequency, and an output part 25 of the signal application part 22 converts an impedance of the probe signal generated by the signal generation part 26 into high impedance, and outputs the same to the conductive panel 12. A signal sensor 23 of an approach detection part 21 detects an amplitude level of the probe signal that appears during the voltage variation of the conductive panel 12, and a signal abnormality detection part 24 of the approach detection part 21 compares the amplitude level of the probe signal detected by the signal sensor 23 with a prescribed threshold value level, and when the amplitude level of the probe signal is less than the threshold value level, an approach detection signal indicating the approach of an intruder toward the security fence 1 is output to an alarm system 3. <P>COPYRIGHT: (C)2012,JPO&INPIT |
