Ex. 5 Read the text and match the headings (1-4) with the gaps (a-d).
1. Television technology
2. Types of Television Sets
3. Benefits of watching TV
4. How television programmes get to the viewers
Television is one of our world’s most important means of communication. It shows us information programmes, like the news, documentaries, and sports events. We can watch films, listen to interviews and hear the sounds of events that happen far away. Television teaches us about countries and cultures and we can enjoy entertainment, like series, comedies, game shows or sitcoms.
A television set can be used for other things as well. You can record shows and films for later viewing, play video games, watch DVDs, or even browse the Internet.
Television has been influencing our lives since it was developed over 80 years ago. It is an important way of spending our free time and shapes people’s opinions about various issues.
In order to produce television you need special TV cameras and microphones which capture the video and audio signals. Three basic colour programmes – red, blue and green can be mixed together to produce any other colour.
The TV signal is carried by wire to an antenna, which is often on a high mountain or building. The signal is broadcast through the air as an electromagnetic wave. These waves can travel through the air at the speed of light but not over very long distances. A good signal can be received up to about a hundred km.
TV stations are given certain frequencies on which they transmit their broadcasts. These frequencies are very high and should not interfere with other signals that travel in the air. In some areas relay towers must amplify the signal and carry it to the next transmitter.
In the last few years digital signals have replaced analog broadcasting. They have many advantages. Picture quality is better and they can carry more data. TV images can be transmitted in a new quality called high definition (HD).
At home an aerial or satellite dish receives the signals and transforms them to create a picture.