How Do Fiber Optics and Cable Television Work

How Do Fiber Optics and Cable Television Work

Posted on by FS.COM

Fiber optical cable and the old common (RF or coaxial) cabke are two different cable system technologies that can be used to distribute various services to end users-homes. In general, they differ only in technical (electrical or communication) point of view. This is mainly important for the network operators because end users or viewers don’t care about the technology, they are insterested in services and TV channels.

There are serveral different methods that can be used to release public services like television channel through a cable television network. Each has some advantages and disadvantages and require different topology structure and network infrastructure.

Analog Television

The first cable television network was just extension of the broadcast in the air. This was implemented by deploying ordinary antenna cable (but with lower losses) from the cable system headend to the homes. Because of distance and many amplifier at a particular point, to ensure that the required signal level. Special communication is one-way, but then most of these cable network to expand to DocSys allows two-way communication need to access the Internet through the use of the system.

This approach can be used with radio frequency coaxial and optical fiber cable. Fiber optic cables are also used in some cases to distribute the old analog cable television. The advantage of optical network because it can use the available fiber in the existing optical fiber cable and the cable loss is very low.

Digital Television

Digital television in cable networks can be divided into two totally different ways of distribution. The first one is an equivalent to digital broadcasting and the other way mainly used in fiber optic networks is IP television.

Digital Cable Broadcastingn

This is equivalent to analog distribution over (RF) cable but with digital signal. The same technology (modulation) can be used as the ground broadcasting but usually, there are more efficient systems, considering the specific properties of the cable system. One typical example is DVB-T system which is used in Europe for digital terrestrial video broadcasting but cables use similar DVB-C system.

IP Television

This is one of the most popular digital television distribution used with fiber optic cable systems. This means that the distribution channels with IP protocol is the backbone of network communication. Each TV channels is encoded with either MPEG-2 or MPEG-4 system and then distributed over fiber optical cable network to the homes. The advantages are enormous. The capacity for the number of channels is pretty high, all the channles can be encoded and distributed with very high quality, it is very easy to distribute HD channels, access to the internet is very simple because of the IP protocol and native technology.

Regardless of distribution cable technology the changes are also happening in the consumer industry. The old CRT television sets are replaced by plasma or LCD flat panel displays and aspect ratio or picture format is also changing from 4:3 to 16:9. Since computer LCD monitors use similar display panels they can be converted to televisions by just adding a simple TV tuner.


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