The leap forward in CCTV system technology has motivated the push towards increased fibre optic use. Today’s high-performance surveillance systems require greater reliability and increased throughput.
In other words, they simply need to get more signals from the camera end to the monitor end, over greater distances, and in harsher environments. A fibre-optic transmission system uniquely preserves the quality of video signals and provides a high level of security. Fibre-optics transmit at higher bandwidths and lower losses and can operate over long distances.
The large signal-carrying capacity of optical fibres makes it possible to provide not only many more signals, but also much more sophisticated signals than could ever be handled by a comparable amount of copper wire. A fibre-optic system can even accommodate multiple CCTV cameras, saving in electrical installation costs. Systems can be configured to include audio and additional data signals as well as CCTV. With fibre, you see sharper pictures over longer distances. A single fibre carries broadcast quality video from 128 cameras up to 992,75 km.
No limit
There is virtually no limit to the amount of video, audio and data that can be transmitted on fibre. A single 0,125-inch fibre supports multiple simultaneous signals. In addition, fibre's high bandwidth lets you transmit broadcast quality audio and video that takes full advantage of today's high-resolution cameras and digital recorders.
Since fibre features a low signal-to-noise ratio, video images maintain high resolution, detail, contrast and colour when transmitted over long distances or through different transmission equipment. Plus, fibre gives you realtime control over remote PTZ cameras, which is what you really want when incidents happen.
Reliability
Fibre-optic cable preserves the integrity of the signal. There are no problems with electro-magnetic interference (EMI), radio frequency interference (RFI), cross-talk or ground loops. You do not have to worry about short circuits, sparks or fire hazards. Once in, you receive clear, sharp pictures, even during storms. If, by chance, lightning strikes one of your cameras, its consequences stop at the camera. Since fibre cannot transmit the electrifying jolt, the rest of the components in your systems remain safe and secure. If you want the signal to get to its destination and to be clear and usable, you have to use fibre.
One of the biggest developments in fibre-optics right now is the introduction of coarse wavelength division multiplexing (CWDM). This recent technological breakthrough allows up to five signals to be combined onto one multimode or single-mode fibre. This breakthrough has provided a new family of digital video multiplexers with up to 170 full-frame, realtime video channels on a single fibre, with or without two-way multiprotocol data (MPD).
Cost effective
Most applications have multiple electronic systems, including fire and burglar alarms, access control, closed-circuit television (CCTV), audio systems, telephones, lighting system controls, and heating, ventilation, and airconditioning (HVAC) systems. They are also likely to have a number of other remotely controlled devices, such as door and gate locks. They have computers; some of these will be integrated into the systems just mentioned and others will be part of the basic business conducted elsewhere.
In short, a modern application will have electronic information all over. To get a vivid picture of what this means in terms of cabling, just push up one of your ceiling tiles and look at the number of cables running in the ceiling. Fibre can replace most of this while providing more versatility and better signal quality at a lower cost. Today's technology allows a wide range of signal combinations to be combined ('multiplexed') onto a single fibre, and can also permit two-way (duplex) transmission of multiple signals.
Like all other high-tech products, fibre-optic links are benefiting from advances in electronics and in manufacturing methods. Surface-mount device (SMD) technology, better integrated circuits, and advances in digital design are producing links that perform better than ever before. New connector designs are making high-quality installation easier, faster, and less expensive.
Since fibre-optics is affected less by moisture, which means less corrosion and degradation, no scheduled maintenance is required. There are virtually no maintenance costs over the life of the fibre, 50 years versus 7-10 years for copper.
Installation hassles eliminated
Installation costs can be the critical variable in a new surveillance system. One of the hidden costs of a digital surveillance system is in the infrastructure of getting images from here to there, from camera to multiplexer or recorder. While most people discuss the ramifications of one camera versus another or which kind of digital recorder to embrace or use, seldom do they discuss the mode of transmission. At some point, the cost of implementing must come to centre stage.
The installation cost to install fibre-optic cable is much less. Copper cables are bulky and stiff to work with. The same installation that would require copper cable an inch in diameter would require a single fibre-optic cable. The alternative, a single fibre in this case, is very small and about as flexible as a piece of string. Multiple fibre cables are also common, but the constant factor here is that, for any collection of transmitted signals, running the fibre will be easier than running the equivalent collection of copper cables.
Fibre-optic cable is versatile. Every video, audio, data, and telephone signal requires its own kind of copper cable. You can have dozens of specialised cables in a typical facility, and few of them are interchangeable. It only takes two types of optical cable to cover all possible signals: multimode and single mode.
It is also important to understand that fibre saves space and weight in a project. For instance, a typical 2- to 4-fibre cable is 87,5% smaller than a typical RG/59 or RG/11 coaxial copper cable or 3-inch twisted-pair copper cable. When you combine fibre's smaller size with its high bandwidth, you get far more capabilities while using much less conduit. Since fibre is exponentially lighter and easier to handle than copper cable, labour and installation costs are further reduced.
Conclusion
The benefits of fibre transmission (small size, light weight, high bandwidth, low loss, noise immunity, transmission security) have established fibre-optics solidly as a major resource for signal transmission. Costs are decreasing as larger quantities are being manufactured, products become standardised and materials required for production of fibre is readily available. Fibre is suitable to meet the changing topologies and configurations necessary to meet operation growth and expansions.
For more information contact Brett Birch, GE Interlogix, 011 805 1590.
This article has some interesting views on the need for increased fibre-optic use in the surveillance industry. The views expressed are not necessarily those of the Editor or Hi-Tech Security Solutions. We invite readers to comment and exchange different points of view regarding those raised in this article.
About the Author
Darren Nicholson is VP-Marketing for GE Interlogix Video Systems Group, which provides optical links to support all classes of equipment used in security and surveillance applications, such as CCTV, access control, audio and all alarm systems.
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