The Using Of FFT In The Leaky Cable Perimeter Intruder System

The main task of perimeter intruder inspection is to inspect the location of intruder exactly and to send an early warning when the illegal intrusion happened. With society and science progressing, the application of perimeter intruder inspection is more and more widely, nearly in all domain of society.The common method and technology of inspection in perimeter intruder are analyzed and studied in this paper. And the leaky cable perimeter intruder inspection technology is selected, which has the lowest rate of missing report, can be secluded well, be little affected by Environment, and be adaptable to various geographical conditions. There are two kind of leaky cable: coupled and radiant, which is applicable to outdoor, field highly security and long perimeter security alarm place. The basic principle of the technique is to bury the leaky cable underground, if the distribution of Electromagnetic Fields changed, the electromagnetic energy received by cable would have changed too, thus we can detect the invasive signal.The paper researched the conventional methods used in perimeter intruder inspection and showed the application of fast Fourier transform (FFT); whose application can improve the detection of this technique on Single Frequency electromagnetic perturbation, and can conduct the detection on multitude electromagnetic perturbation.The paper showed the detection on multitude electromagnetic perturbation with FFT, whose application not only realizes the detection of multitude electromagnetic perturbation, but also solves the difficulty in detection on multiple invasive signals simultaneously for perimeter intruder inspection, further more, it simplified the detection circuit and make it easier for integration. The paper realized the simulation research on the detection of multitude electromagnetic perturbation...