The difference and selection of vibrating fiber and leaky cable
Among the various security systems, as the first protection at the outermost periphery, the perimeter alarm system is a very important part. There are also many types of perimeter alarm systems. The more commonly used ones are infrared radio systems, pulsed electronic fences, etc. Occasionally, vibrating optical cables and leaking cables are also used. What is the difference between a vibrating cable and a leaking cable? How to choose?
fiber optic cable
1. The transmission medium of the two is different
The structure of the leaky cable is basically the same as that of the ordinary coaxial cable. It consists of three parts: an inner conductor, an insulating medium and an outer conductor with periodic slots. The vibrating fiber uses a single-mode fiber optic cable. Therefore, there is a certain difference in the installation method between the two. The vibrating optical fiber requires special optical fiber splicing, while the leaky cable does not.
2. The working principle is different
The leaky cable mainly forms an invisible cylindrical electromagnetic field protection area between the two leaky cables laid. When the human body and the metal body move in this area, the electromagnetic field disturbance will be caused and the detector will detect it and generate an alarm. Signal. For non-metallic bodies or non-human bodies, such as branches, etc., since the interference to the electromagnetic field is extremely weak, although it moves in the protection area, it cannot cause disturbance of the electromagnetic field, so it will not alarm. By adjusting the sensitivity of the detector, the interference of small animals, such as puppies, kittens, etc., moving in the protection area can be filtered out, so as to achieve the purpose of effective protection.
Vibrating fiber: When the fiber is vibrated, part of the characteristics of the transmitted light in the fiber will change. By configuring special sensing equipment, after signal acquisition and analysis, the characteristics of light (i.e. attenuation, phase, wavelength, polarization, etc.) can be detected. , mode field distribution and propagation time) changes. The change of light characteristics is processed by the special algorithm and analysis of the alarm controller, and the third-party intrusion behavior and normal interference are distinguished, and the alarm and positioning functions are realized.
In addition, because the leaky cable system mainly detects intrusion by the invisible electromagnetic field generated, the operation of the system itself not only needs to consume power, but also is not suitable for areas with electromagnetic interference or fear of electromagnetic interference, and also suffers from thunderstorms. It cannot work properly due to the influence of lightning. At the same time, the nominal length of each leakage cable is 100 meters, which limits the maximum extent of each defense zone to within 100 meters. When laying, the induction cable is placed in the middle of the 5-meter-wide strip area (the construction area is wider, resulting in a large amount of work), away from any active metal objects, and the induction cable is at least at a distance from large active metal objects such as chain fences. 3 meters away (susceptible to moving metal objects, not suitable for close to the road; the length of the construction area has to be enlarged in case of iron perimeter).
The vibrating optical fiber system does not need power supply because the optical fiber is passive, because the laying is convenient, flexible, safe, and can achieve high concealment. It is easy to integrate into the surrounding environment; at the same time, it also has no external signal radiation, anti-electromagnetic interference and radio frequency interference; and corrosion resistance, strong resistance to changes in external environment and temperature. It can normally carry out 24-hour preventive work in various outdoor harsh natural environments, and its service life can be as long as more than 20 years.