The principle reasons for using optical fibre as the transmission media in CCTVapplications are:
· The maintenance of picture quality and control data integrity over extended distances:
This is the main reason for the use of fiber optic signal strength than loss characteristics of copper cable. In general, the attenuation of coaxial cable to a the signal frequency of 5 MHz, 20 dB / km. In mitigation of fiber comparison is 0.3 to 3 dB / km mean that the fiber optic transmission distances of 60 km and can achieved, depending on exact details of the application. In addition to this low signal loss on fiber frequency range of the signal very large, so that made optical fiber can be used for transmission of multiple video signals over long Distances.
· Immunity to electromagnetic interference:
Optical fiber transmits signals as light pulses instead of electrical impulses. This light transmission is not the existence of electromagnetic fields. As fiber transmission can lead to applications where connections are used routed away from power lines and electrical machines. This includes applications such as railways, tramways, electricity generation and vehicle welding machines. In addition to the optical fiber generally has a metal structure there is no problem with ground loops between devices and The cable can be transmitted lightning impulse. This makes the elimination of ground loop Fiber optic cable for the medium of choice for strengthening links between the most accessible.
· Security of Information and Operational Safety:
Unlike copper wire cables with fiber optic does not emit signals from fiber The cables are virtually immune to “strike”, then the signal is difficult to Access to unauthorized persons. As there is no emission of optical fiber there is no danger of a plant fiber to act as a source of ignition. This means that fiber can be used in hazardous areas such as chemicals and petrochemicals Web sites that a true “intrinsic safety” of the transmission. However, note that This internal security, not the electro-optic modems extend the termination who have certified the safety and protection as other electrical equipment.
· Efficient use of duct space:
Optical fiber itself is very small, each fiber is only 0.125 mm in diameter. Protective coating is then applied in stages, depending on demand, making the fiber in a cable used. Typically the resulting cable has an appropriate diameter of 3mm for a patchlead heart of 8mm for single fiber or a fiber of eight for internal or external. In contrast, 75 ohm coaxial cable has a copper-CT100 Diameter of 6.5 mm. Thus we see that the small size of the optical fiber to allow significant savings on copper, where space is limited or if Duct space is limited. With the small size of fiber weight gain both to achieve economies of storage and transportation prior to installation.
· Multi-channel capability and “Future Proofing”:
While most fibers are now used for CCTV video signal is transmitted and can be Data to a control signal may wish the user to update the system to support more Camera and control channels. Each fiber glass is now able to transfer several optical channels, either by using different optical media “colors”, ie division multiplexing wavelength, or increasing the frequency of the signal with Electric multiplexing techniques. The transmission media is so “future proof” and extend the connection should the link for additional devices Capacity
Source: http://www.fiber-opticis.com
The Code Factory I.T. Solutions 