Increased fibre-optic use is a direct result of the jump forward in closed-circuit television (CCTV) system technology. Today’s high-performance surveillance systems require greater reliability and increased throughput. Simply put, they have to get more signals from the camera end to the monitor end, over larger distances and in more difficult environments.
A fibre-optic transmission system not only preserves the quality of video signals, but also provides a high level of security. Fibre-optics transmit at higher bandwidths, with lower losses. What is more, they operate at distances five times greater than coaxial cable.
Not only do optical fibres make it possible to provide many more signals, but they also carry more sophisticated signals than a comparable amount of copper wire could ever accommodate. That is because optical fibres have a much larger signal-carrying capacity. A fibre-optic system can even handle multiple CCTV cameras, big savings in electrical installation costs. Systems can be configured to include audio and additional data signals as well as CCTV.
Furthermore, fibre provides sharper pictures over longer distances. Beyond 229 m, twisted pair copper cable requires amplifiers or repeaters. Coaxial copper cable will extend to 305 m. 322 m does not go very far in many applications. That is the basic distance from the end of one building to the far end of the next. Fibre gives you more than 6 km of transmission, without costly repeaters or amplifiers. A single fibre carries broadcast quality video from 128 cameras up to 993 km.
A virtually unlimited amount of video, audio and data can be transmitted on fibre. A single 3,175 mm fibre supports multiple simultaneous signals, far more than conventional copper cable. In addition, fibre's high bandwidth allows transmission of broadcast quality audio and video, taking full advantage of today's high-resolution cameras and digital recorders.
Because fibre features a low signal-to-noise ratio, video images preserve high resolution, detail, contrast and colour when transmitted over long distances or through different transmission equipment. Plus, fibre offers realtime control over remote PTZ cameras, which is critical when incidents occur.
Fibre offers the utmost in reliability. Fibre-optic cable maintains the integrity of the signal. Problems with electro-magnetic interference (EMI), radio frequency interference (RFI), cross-talk or ground loops are nonexistent. Short circuits, sparks or fire hazards become a thing of the past. Once installed, fibre provides clear, sharp pictures, even during inclement weather. If, by chance, lightning strikes a camera, damage is limited solely to that camera. Because fibre cannot transmit the electrifying jolt, the remainder of the system remains safe and secure. To get a signal to get to its destination and be clear and usable, fibre is a must.
Fibre is also tough. For example, the GE Security Omega Series transmission equipment will provide more than 100 000 hours, over 11 years, of day-in, day-out reliability. With an operating temperature range of -40 to +75°C, fibre systems are ideally suited for harsh outdoor and/or industrial environments.
The introduction of coarse wavelength division multiplexing (CWDM) is one of the biggest developments in fibre-optics today. This recent technological breakthrough allows up to five signals to be combined onto one multimode or single-mode fibre. It has also 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).
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 moving images from one place to another, from camera to multiplexer or recorder. While most people discuss the benefits of one camera versus another, or which kind of digital recorder to use, rarely do they consider the mode of transmission. At some point, the cost of implementing must become paramount.
It costs a lot less to install fibre-optic cable than to install copper cable. Copper cables are bulky and difficult to manoeuvre. An installation requiring copper cable 25 mm in diameter would require just a single fibre-optic cable that is very small and about as flexible as a piece of string. Multiple fibre cables are also common, but the point to remember is that, for any collection of transmitted signals, running the fibre will be easier than running the equivalent collection of copper cables.
Another big advantage - fibre-optic cable is versatile. Every video, audio, data and telephone signal requires its own kind of copper cable. A typical facility may use dozens of specialised cables, and few of them will be interchangeable. Yet it takes only two types of optical cable to cover all possible signals: multimode and single mode.
It is also important to note that fibre saves space and weight in a project. Labour and installation costs are further reduced since fibre is exponentially lighter and easier to handle than copper cable. A typical 2- to 4-fibre cable is 87,5 and smaller than a typical RG/59 or RG/11 coaxial copper cable or 76 mm twisted-pair copper cable. For instance, 60 kg of fibre can do the job of 7258 kg of coaxial copper cable!
Setting up a system using copper or many fibre-optic transmission systems can be a hassle because of intensive trial-and-error troubleshooting. The GE Security Omega Series lets installers test the fibre network and quickly diagnose problems before installing a single camera by utilising its on-screen display. One bar on the monitor means the video camera has malfunctioned. Two bars indicate a problem with the cable. If there is no video input, the installer will see a test pattern.
On-board test generators allow an installer to perform system checks without test equipment, speeding up the entire process. At any time, the installer can check realtime status monitoring of level/loss, video, audio, data input/output and other system functions.
Fibre installs faster. It is that simple. Fibre also accepts the changing topologies and configurations necessary to meet growth and expansion. If you are looking to upgrade and reconfigure system designs, technologies such as wavelength division multiplexing (WDM), optical multiplexing, and drop and insert technologies are available.
Additional fibre savings
Video transmission actually costs less when fibre is used instead of copper coaxial cable. Most applications call for multiple electronic systems, including fire and burglar alarms, access control, closed-circuit television (CCTV), audio systems, telephones, lighting system controls, and heating, ventilation and air conditioning (HVAC) systems. A typical configuration is also likely to include a number of other remotely controlled devices, such as door and gate locks. They also have computers. Some of these will be integrated into the systems mentioned above and others will be part of the basic business conducted elsewhere.
In short, a modern application will have a sprawl of electronic information. 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 cable while giving users more versatility and better signal quality at a better 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.
Fibre-optic links are benefiting from advances in electronics and in manufacturing methods, as are all other high-tech products. Surface-mount device (SMD) technology, improved circuit integration and advances in digital design are producing links that perform better than ever before. New connector designs make high-quality installation easier, faster and less expensive.
Fibre-optics also offers a significant advantage over copper cable when it comes to maintenance costs. Because fibre is affected less by moisture, it is also less susceptible to corrosion and degradation. Fibre requires no scheduled maintenance and there are virtually no maintenance costs over the life of the fibre. That is especially important when you consider that fibre has a 50-year life span, versus seven to 10 years for copper.
When you combine fibre's smaller size with its high bandwidth, you get many more options while using much less conduit.
Fibre has become the transmission method of choice
Fibre-optics is now a major resource for signal transmission because of its many benefits, including its small size, light weight, high bandwidth, low loss, noise immunity and transmission security. Costs are declining as larger quantities are being manufactured, products become standardised and materials required for production of fibre are readily available. Fibre is able to meet the changing topologies and configurations necessary to accommodate operation growth and expansions.
For more information contact Darren Nicholson, GE Security, 09714 427 2004, [email protected]
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