In today;s network HD monitoring camera system application, Optical fiber Is a way all connections can provide the best performance of the bandwidth. The use of optical fiber transmission system, image quality system is only limited by the camera, the environment and the monitor of these three factors, and the optical fiber transmission system can be transmitted to the image distortion very far away will not make the signal in any form, more do not detract from the clarity of the picture or image details. It can be said that the fiber transmission system is the lifeline of the entire monitoring system.
A type of optical fiber
Fiber according to the use of different occasions, divided into indoor outdoor fiber, optical fiber, optical fiber branching, fiber optic wiring.
According to the method of laying points: self bearing optical fiber, optical fiber, overhead pipeline buried armored fiber and submarine optical fiber.
According to the structure of the optical fiber bundle: cengjiaoshi fiber, optical fiber, optical fiber, optical fiber type skeleton type clasp, belt type optical fiber, optical fiber and optical fiber non metal branch.
Purpose: optical fiber for long distance communication, short outdoor fiber, fiber and hybrid fiber in buildings;
Fiber can be divided into single-mode and multimode transmission mode according to the monitoring, generally using single-mode fiber.
Only a single mode optical fiber transmission mode optical signal of the optical fiber, the conventional G.652, G.653, G.654, G.655 and other transmission level classification, dozens of kilometers of single-mode fiber transmission distance up to 100m signal. The single-mode fiber, only the main transmission mode, that is light only along the inner core optical fiber transmission, due to completely avoid the mode dispersion makes the transmission bandwidth of single-mode fiber is very wide, so it is suitable for large capacity, long distance optical fiber communication, optical fiber using single mode wavelength 1310nm or 1550nm.
Multimode fiber: fiber optic transmission modes of the optical signal in the G.651 grade, according to the optical mode is divided into OM1, OM2, OM3, multimode fiber transmission fast signal far transmission distance of 2 km. In the multimode fiber, the wavelength of the work, there are many modes in optical fiber transmission, the optical fiber is called multimode fiber, due to dispersion or aberration, so the poor performance of the optical fiber transmission bandwidth is narrow, transmission capacity is relatively small, relatively short distance.
Two, fiber laying methods and requirements
The conventional outdoor fiber are loose tube as the core container, as the most common optical fiber laying mode; common indoor fiber sleeve type laying; core core fiber is the combination of laying fiber core in bands.
Optical fiber laying: bending radius of the fiber should be at least 15 times the diameter of the fiber, in the construction process should be at least 20 times; fiber cloth, fiber optic disc rotation should be placed with the synchronous speed, fiber index average speed of 15 meters per minute; cloth fiber, fiber optic disc to maintain relaxation of the arc, and keep the buffer margin, and should not be too much to avoid the back button in optical fiber; fiber ends reserved length of 5-10 meters; laying fiber should label, and fill line records; all fiber should not be exposed.
Three, core selection
The number of the fiber core is contained in each fiber Glass The number of fibers. Introduce the following small series to determine the fiber core number method.
First, know the number of wiring layers of units to calculate the switch, switch is connected between the stack or stack. If the stack, the core switch for hot standby redundancy, 6 core enough (2 units each core with 2 cores, 2 Xin Rongyu). If you do not stack a switch to 4 core switch number multiplied by 4 plus 4 core redundancy can be. (Note: redundant: as long as more and more, the main production is redundant: one with another, exactly the same as backup; backup: at the same time in the working state; cold backup: backup device is in the standby state. )
Experience: each floor wiring (horizontal wiring cabinet), between a single fiber, generally six core: two core, two core, two use of spare core redundancy; also use eight core fiber. The minimum configuration specification of each of the 48 points 2 core. Of course, the 48 points available for 4 core, 2 core fiber as the smallest unit, leaving 2 core as a more appropriate preparation.
The above is the method to determine the fiber numbers, we can find out. Backup can vary from person to person should be selected, so the fiber core is more different, choose only to ensure a minimum selection plus a backup core number can be according to the standard.
Four, pay attention to
In addition to the selection of optical fiber core and fiber types, but also the outer sheath fiber will be selected according to the use of optical fiber, the selection should pay attention to the following points:
1 outdoor buried fiber, metal clad fiber should be selected, overhead, fiber black plastic sheath can choose two or a plurality of reinforcing ribs of the.
2 buildings with the fiber should be paid attention to in the selection of the flame retardant and smoke, toxic characteristics, generally in the pipeline and forced ventilation, can choose the flame retardant and smoke type, selection of flame retardant and smokeless and non-toxic type should be exposed to the environment.
3 building vertical wiring, can choose cengjiaoshi fiber; the horizontal wiring type, can choose the branch fiber.
4 transmission distance within 2km can choose multimode fiber; more than 2km can be used to relay or single-mode fiber.
These are a few questions from the application into consideration, the implementation time needed to master. In fact, the wiring environment is complicated, various problems may occur at any time, which we need in the planning and construction in strict accordance with the standard implementation problems, wiring, flexible analysis, will be resolved.
