Unit 21: Understanding Video Technology

Broadcast Systems and Television Standards

There are three different television systems:

NTSC

This is the standard format in the United States, but has been adopted in other countries like Japan, South Korea, Taiwan and the Philippines. The first NTSC standard was developed in 1941. In 1953, a modified version of the NTSC standard was adopted which allowed colour television broadcasting to be received. NTSC was a widely adopted broadcast system until it was replaced with Digital ATSC. NTSC is based on a 525 line, playing at 30 frames per second at 60HZ. Since it was first developed without consideration for the addition of colour, the added effect of colour into the NTSC format has been the system's weakness.

SECAM

Though work began on SECAM as early as 1956, the technology wasn't made ready for general use all the way until 1967, when further improvements to the compatibility and image quality had been made. Though it was first introduced in France in 1967. it was adopted by many parts of Eastern Europe. Like PAL, SECAM is based on a 625 line, playing at 25 frames per second, but is uses a different colour management system than both PAL and NTSC. Countries on the SECAM system include France, Russia, Eastern Europe and parts of the Middle East.

PAL (Phase Alternate Line)

PAL was first developed by Walter Bruch at Telefunken, a German radio and television company, who patented it in 1962. The first ever broadcasts began in the United Kingdom and West Germany in 1967. As a format, PAL is now used across most of Europe. The PAL format is based on a 625 line, plays at 25 frames per second, on a 50HZ system. The signal is interlaced into two fields composed of 312 lines each. This allows for a better overall picture because of the increased amount of scan lines. However, because fewer frames are displayed per second, a slight flicker in the image can sometimes be noticed.

Three different television systems around the world.

Satellite, Cable and Internet as Broadcast Systems

Satellite
Formed in 1990, Sky is a Satellite Broadcasting Company and is the largest Pay-TV Broadcaster in the UK and Ireland with over 10 million subscribers. Sky offer a diverse range of channels including their exclusive chanels: Sky One, Sky News, Sky Sports and more. They also offer channels in HD and even 3D, but these come at an extra cost.

Sky is a form of Satellite Television. This is Television Programming delivered by the means of communications satellites and received by an outdoor antenna. Some major disadvantages to using Satellite Television are the extra costs associated with using it to its full. These costs can include paying to access extra channels. Also, the price of Satellite Television increases as more televisions are connected.

Cable
Formed in 2006, Virgin Media was the first quadruple-play company in the UK, offering television, internet, mobile and landline services.

Virgin Media is a form of Cable Television. This is a system of distributing television programs via radio frequency, which are transmitted through coaxial cables or light pulses through fibre-optic cables. This is usually a stable and inexpensive option. However, many areas only have a single cable television provider.

Internet
Internet television is the digital distribution of television via the internet. BBC iPlayer is a form of Internet Television, allowing for free and on-demand viewing of the latest television. However, not all forms of internet Television allow free access to on-demand television. For example, Sky Go requires a Sky subscription. Though both of these examples are website-based, they can also be accessed through Androids, iPhones and even games consoles.