Television Technology

In order to produce television you need special TV cameras and microphones which capture the video and audio signals.  Three basic colors – red, blue and green can be mixed together to produce any other color.

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.

 

How TV signals are transmitted

How TV signals are transmitted

 

How television programs get to the viewers.

Television programs get to viewers in three ways.

  • Television signals can be broadcast through a transmitter, a large structure that sends audio and video signals to people’s homes. You receive these signals through an aerial which, connected with a cable, brings that signal to your TV set and changes it into an image.
  • Cable television delivers hundreds of TV stations to viewer’s homes through a series of cables. Some channels specialize in certain fields like movies, others broadcast sporting events or documentaries.
  • Satellite television emerged in the 1980s. Viewers receive their TV signals directly from one or more satellites that are in a geostationary orbit. You need a dish-shaped antenna to receive such programs.

 

 

Television - Table of Contents

 

Television - Online Exercises

Words:

  • advantage = good sides
  • aerial = antenna ; structure that is used for sending and receiving TV signals
  • amplify = to make stronger
  • analog = using a wave in its original form
  • antenna = long thin bar used for receiving and sending signals
  • basic = main
  • broadcast = send a television signal
  • capture = get
  • carry = bring
  • certain = special
  • channel = TV station
  • digital = using a system of ones and zeros
  • dish-shaped = form of a bowl
  • distance = from one place to another
  • electromagnetic wave = waves caused by electricity and a magnetic field
  • emerge = come up , start
  • frequency = the number of waves that pass any point in one second
  • geostationary orbit = a satellite that is in a fixed position above the earth and rotates together with it
  • interfere = get mixed up with
  • receive = get
  • relay tower = a structure that receives a signal and sends it to another tower
  • replace = to exchange for something else
  • specialize = focus on
  • structure = here: tall object made of metal
  • transform  change into
  • transmit = broadcast, send
  • viewer = a person who watches television
  • wire = thin, round piece of metal that can carry signals