Cable television (CATV) is a broadcast distribution system that uses a network of cables to deliver multiple types of media services. In the United
States, companies (such as CATV) that provide programs over multiple
transmission channels are called multichannel video programming distributors (MVPDs).
While CATV systems might use coaxial cables for a majority of customer
connections, many CATV systems also use fiber optic cables and microwave
transmission connections to transfer some of their signals.
Figure 1.1 shows a sample CATV system. This diagram shows that the
CATV system gathers content from a variety of sources including network
feeds, stored media, communication links and live studio sources. The headend converts the media sources into a form that can be managed and dis
tributed. The asset management system stores, moves and sends out (playout) the media at scheduled times. The distribution system simultaneously
transfers multiple channels to users who are connected to the CATV system.
Users view CATV programming on televisions that are directly connected to
the cable line (cable ready TVs) or through adapter boxes (set top boxes).
CATV systems were originally created to overcome some of the radio transmission challenges of early TV broadcast systems. In 1941, television broadcast services were providing news and entertainment to listeners by wireless broadcasting. Because television broadcast systems could only provide
wireless coverage to a limited geographic area (such as a city), in 1948, people and companies began to be setup systems to deliver television signals in
other areas by interconnection cables. These early analog cable television
systems simply captured television signals in one geographic area by a
receiving antenna and retransmitted these television channels in other geographic areas by a transmitting antenna.