Digital Information

Overview

As we have seen, a computer manipulates binary data.

All kinds of informations must be converted first in "0" or "1".

But this conversion introduces often losses.

Some examples

How to describe letters ?

The standard ASCII table describe the letters :

Example ADNA  is coded : 41 44 4E 41

How to describe a color ?

The standard picture files  need 24 bit words to describe a color. This suppose that there are 224 different colors.

How to describe a picture ?

The contents of a JPG file looks like this :

But we lose informations :

Visible after a zoom :

How to describe a sound ?

It's the same story... hex code which describes binary words

But we lose informations. The audio quality is not so fine.

How to transmit data through the Internet ?