The mapping of events to messages is called encoding. Messages are recorded in information storage units. The recorded message itself is an event system. Encoding is a transformation, based on the mutual and unambiguous correspondence between two event systems.
The tool of encoding is code. A code consists of a finite set of symbols (an alphabet) and coding rules (groups of symbols).
A code-word is an elementary message, which consists of a finite number of symbols. The code's syntax is the set of code symbols and the rules for forming code-words.
Encoding changes the information's form, but other information characteristics remain unchanged. There are fixed-length and variable-length codes.
Basic Types of Codes:
| Fixed-length code | Variable-length code |
|---|---|
| Technical codes | Morse code |
| Communication Codes | Human languages |
| Computer codes | Technical languages |
For a fixed (n) length binary code, the number of possible codewords is:
$$ N = 2^n $$
If we form codes from m different symbols, then the number of possible n-length codewords is:
$$ N = m^n $$
The fundamental problem of coding theory is the preservation, security, and maximization of the information content of transmitted messages.
Morse Code
Morse code is a method of encoding text characters into sequences of dots and dashes (or short and long signals) that can be transmitted over telecommunication lines or other mediums like light or sound. It was originally developed in the 1830s by Samuel Morse and Alfred Vail for use in telegraphy.
Key features:
Examples:
Example message: