How do fiber optics and cable TV work?
Fiber optic cable and old common (coaxial or RF) cable are two different cable system technologies that can be used to deliver various services to end users – homes. In general, they only differ from a technical point of view (electrical/communications). This is mainly important for network operators because end users or viewers don’t care about technology, they are interested in TV services and channels.
There are a few different ways that can be used to distribute common services like TV channels over cable networks. Each has some advantages and disadvantages and requires a different network topology or infrastructure.
analog television
The first cable television networks were simply an extension of broadcasts on the air. This was implemented by deploying ordinary (but lower loss) antenna cable from the headend of the cable system to homes. Due to the distances, there were also many amplifiers at specific points to guarantee the required signal levels. Communication was exclusively one-way, but later most of these cable networks were extended to allow the two-way communication needed to access the Internet through the use of systems such as DocSys.
This approach can be used with both RF (coaxial) and fiber cables. Fiber optic cables are also used in some cases to distribute old analog cable television. The advantage of optical network is that it can use the available fibers in existing fiber optic cables and the cable losses are very low.
digital television
Digital television on cable networks can be divided into two totally different forms of distribution. The first is an equivalent to digital transmission and the other form used mainly in fiber optic networks is IP television.
digital cable broadcasting
This is equivalent to analog cable distribution (RF) but with a digital signal. The same technology (modulation) can be used as for terrestrial broadcasting, but there are generally more efficient systems that take into account the specific properties of cable systems. A typical example is the DVB-T system used in Europe for terrestrial digital video transmission, but cables use a similar DVB-C system.
IPTV
This is the most popular digital television distribution used with fiber optic cable systems. It means distributing television channels with the IP protocol, which is the backbone of Internet communications. Each TV channel is encoded using the MPEG-2 or MPEG-4 system and then distributed over the fiber optic cable network to homes. The advantages are enormous. The capacity for the number of channels is quite high, all channels can be encoded and distributed with very high quality, it is very easy to distribute HD channels, Internet access is very simple due to IP protocol and native technology.