Coding and decoding

Содержание и основные понятия

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Alterna · Chapter 11 · 11.1
Coding and decoding
What is coding, why it's needed, examples from life and in a computer.
Codeing
- Presentation of information by symbol.
Decoding
It's the reverse process: the code to the original form.
GEF
PIF
OGE No. 1-4
01
What is coding?
Definition and examples from GEF
GEF
Definition for GEF
Codeing
is the process by which information is presented in a given form by means of symbols (code).
Decoding
is the process of converting the coded message back to its original form.
Examples of coding from life
Type of code
Example
Which codifies
Morse code
... --- ...
SOS points and dashes
Strich code
||||| |||||
Price, goods
Semaphorus
Position of the flags
Letters
Road signs
Form + Color
Traffic rules
Note Record
Note on the Line
Sounds of music
QR code
Black and white pixels
Text, URL
Binary code
01001000 01101001
Text in Computer
Coding and decoding process
Information
Reference form
RCD
RCD
Coded Message
DECOD
Information
Re-established
02
Why does it need coding?
Three main reasons
GEF
OGE No. 1-4
Storage and transfer
The computer only works with a binary code (0 and 1). All information should be presented in a binary form.
Universality
The same binary code can represent text, images, sound, video.
Protection
The encryption is a type of coding to protect information from unauthorized access.
03
Interactive cryptographer
Enter the text and get its binary code.
🔐
Text: \Double code
Enter text:
04
Equitable and uneven coding
Two approaches to GEF coding
Equal
Each symbol is coded by the same number of bits.
A=00, B=01, C=10, D=11
Каждый = 2 бита
Example: ASCII, Unicode (UTF-32)
Uneven
Different characters are coded by different numbers of bits.
A=0, B=10, C=110, D=111
Длина разная
Example: Morse code, UTF-8
05
Graph: N = 2i
Move the slider - see the power of the alphabet increase
GEF
EEG / EEG
📈
Interactive graph · N = 2i
Symbol Weight
i
(beat):
8
N = 2
8
=
256
256 different symbols
= standard coding (1 byte)
06
Bit oscillographer
The visual animation of the bit flow -- see the text turn into electrical impulses.
📡
Bit oscillographer
Enter the text for the animation:
Speed (beat/s):
3
Enter the text and press "Animize." Each byte is translated as: start-beat (low) 8 bits of data ♪ stop-bat (high).
■
high level (1)
■
Low level (0)
📝
OGE/EGB task bank
🎯
Quest: Encoding
Question 1 / 5
XP: 0