Representing the real world digital form

• Analogue representation


  A direct counterpart (analogue) of the real-world aspect that we are trying to capture
• Analogue representation


  • Analogue clock
  • Traditional mercury- or alcohol-in-glass thermometer
• Digital representation


  Values are converted into discrete values
• Digital representation


  • Digital clock
  • Digital thermometer
• Analogue temperature


  Can take on any value within a given range
• Digital temperature


  Can only display a finite number of digits
• Many quantities are essentially discrete, in that there is only a fixed range of values they can take
• Discrete quantity


  Something that can be counted
• Continuous data


  Data that is measured
• A key factor in the rise of digital communication and data storage is that almost any analogue quantity can, in principle, be represented digitally