Coding - Definition and Overview

The term coding has the following meanings:

1. In communications systems, the altering of the characteristics of a signal to make the signal more suitable for an intended application, such as optimizing the signal for transmission, improving transmission quality and fidelity, modifying the signal spectrum, increasing the information content, providing error detection and/or correction, and providing data security (Note: A single coding scheme usually does not provide more than one or two specific capabilities. Different codes have different sets of advantages and disadvantages.)
2. In communications and computer systems, implementing rules that are used to map the elements of one set onto the elements of another set, usually on a one-to-one basis
3. The digital encoding of an analog signal and, conversely, decoding to an analog signal
4. Computer programming
5. The process of classification of information (vs. use of "free text" e.g. in Medical Informatics)

Source: Federal Standard 1037C

See also

• Code
• Entropy coding

External links

• The on-line textbook: Information Theory, Inference, and Learning Algorithms (http://www.inference.phy.cam.ac.uk/mackay/itila/), by David MacKay, contains chapters on data-compression codes (including symbol codes such as Huffman codes, and arithmetic codes); hash codes (which are used for verifying data integrity and for rapid information recall); error-correcting codes (including elementary error-correcting codes, the theoretical limits of error-correction, and the latest state-of-the-art error-correcting codes, including low-density parity-check codes, turbo codes, and digital fountain codes).