1. C021TV-I1-S1

2. ICN : 1. Binary coding 1. Data representation as bits
2. Store images or sounds
3. Compression
4. Data organisation
5. Database
Introduction de la semaine 2/2
Présentation du sommaire global de la semaine : apparition progressive des éléments de la liste, puis mise en évidence de la portion concernée par la vidéo.
Mise en évidence = police noire + gras
Nom abrégé de cours - Enseignant

3. Digitalisation and digital coding
Why code information?
Various and heterogenous information, more or less structured
Picked up by human senses or tools
How to represent it?
Digitalisation and digital coding

4. At electronics level
Either the electrical current passes, or it does not
Binary coding with 0 or1
Bit = Binary Digit
Today’s computers are based on electronics
Soon, photonics or quantics?

5. Bits operations Transistor = miniature switch
A tap to manage the electrical current

6. Bits operations Transistors create logical gateways OR X Y Z 0 0 0
AND, OR, exclusive OR, …
Then bit adders, … OR
X Y Z
0 0 0
0 1 1
1 0 1
1 1 1 X Z Y

7. The computer can handle the most common kinds of numbers
Code numbers
Bits are limited to 2 values
Assemble bits to code higher numbers
One byte = 8 bits = 256 values (from 0 to 255)
To code an age, only 7 bits are needed (from 0 to 127)
To code temperatures, ilmore is needed
Negative numbers
And also decimals
The computer can handle the most common kinds of numbers
Mais il n’a aucune idée des unités, de leur signification, etc
Nom abrégé de cours - Enseignant

8. Doesn’t matter what’s inside
The computer can handle numbers
But it doesn’t care what they mean
The programmer or the user has to enter the numbers the right way
What measurement unit?
Understand the results correctly
Nom abrégé de cours - Enseignant

9. The font’s drawing (typeface) is only needed for display
Code text
Many ways to store a letter
One bit per box to display?
What height and width?
What if we add colours?
ASCII code
8bits numeral = 256 possible characters
Extended by Unicode to manage all languages
The font’s drawing (typeface) is only needed for display

10. To sum it up The electrical current codes bits 0 or 1
Those bits are assembled to represent numbers, or letters, etc.
Electronic circuits perform calculations with those numbers
Without knowing their signification

11. Illustrations
p. 2 : _1315_2558-Bimetall-Zeigerthermometer.jpg CC-BY- SA-3.0 ( , via Wikimedia Common
p.2 : Little visuals :