Up until relatively recently, all television broadcasts, whether they were terrestrial, satellite, or cable, were analogue. If you wanted to watch a television show, all you needed to do was plug an aerial into the back of your TV and tune it in. If you weren’t getting a perfect signal, you could still watch the programme, but it would often be fuzzy or lacking in colour information. In the UK, there were only a few channels available on terrestrial TV, and if you wanted more choice you had to invest in a satellite dish or a cable TV connection.
In the 1990s, a new technology emerged called digital television, which enabled broadcasters to fit a lot more information into the waveforms that carried the TV signals from transmitter to receiver. This meant that they could fit a lot more channels into the electromagnetic spectrum, as well as a wealth of additional information such as bonus material and interactive games. The picture tended to be much sharper, and was much better suited to the new generation of flat screen LCD and plasma screens. All that was required was a set-top box to decode the digital TV signals, or a new generation of satellite or cable box.
However, early digital TV was not without its problems. In particular, the terrestrial broadcasts were extremely jittery and unreliable in many areas, and if you wanted a half-decent signal you had to invest in an outdoor broadband aerial, which often cost as much as a year’s subscription to a satellite or cable TV service. During this time, satellite and cable TV became a lot more popular, as it enabled people to enjoy the new digital television and radio broadcasts without any of the problems associated with the terrestrial digital technology. However, once all of the old analogue transmissions are switched off, it is expected that terrestrial TV reception will improve due to the increased bandwidth. For more information about the digital TV switchover, go to the Sky website.
Another one of the benefits of digital TV is that it is better equipped to deal with new technologies, such as high definition and 3D TV. It also makes it possible to record huge amounts of information, without any signal degradation, onto a relatively small hard drive. While it was possible to record live analogue TV onto a removable medium such as VHS or DVD, there was always a slight loss of quality when you did so, and you could only store a few hours on each tape or disc. With a hard disc or solid state recorder, you can record hundreds of hours of live TV onto one unit, and the quality will be exactly the same as if you were watching it live.