analogue vs digital

Analogue Data Transmission

Data can be transmitted from one place to another via analogue data transmission.  This is the technique has been used to transmit television and radio signals since the discovery of radio waves.  Analogue transmissions involve fluctuations in either the frequency or the amplitude of the signal.  When the frequency is changed (modulated) to indicate the information being transmitted this is known as frequency modulation(FM as in 5FM or Algoa FM).

The image below shows a wave where the wavelength and the amplitude are indicated.  When the wavelength is decreased the frequency goes up because the speed of all electromagnetic radiation in theory travels at the same speed

When data is transmitted using digital data transmission the signal is either on or off, there is never a signal that between the on and off position.  Digital provides us with a far more efficient mechanism for moving data because we can make much more efficient use of the bandwidth than we can with analogue.  It is for this reason that South Africa is going to have all the analogue terrestrial broadcasts turned off by 2015.