Codes - Chris Sawer
29th March 2003
You will almost certainly have used a code today without even realising it. Have you had a conversation on a mobile 'phone? Sent an e-mail? Typed a letter on a computer and saved it to disc? Watched digital TV or listened to digital radio? Listened to a CD? Bought an item in a supermarket which has had a bar code 'scanned' at the checkout? All of these things involve digital data being transferred from one place to another. There are many different ways of doing this, but none are perfect - there is always the possibility that errors may creep in.
How come, then, when you reload that word-processed letter, that nothing has changed? Why isn't there horrendous interference on your mobile 'phone when the signal isn't very strong? The answer to these questions is the same - the information has been encoded so that errors can be detected and, if possible, corrected. This presentation looks at ways of encoding information, covering an introduction to group codes and generator matrices.