Page "Digital" Paragraph 10

* Errors: Disturbances ( noise ) in analog communications invariably introduce some, generally small deviation or error between the intended and actual communication.

Disturbances in a digital communication do not result in errors unless the disturbance is so large as to result in a symbol being misinterpreted as another symbol or disturb the sequence of symbols.

It is therefore generally possible to have an entirely error-free digital communication.

Further, techniques such as check codes may be used to detect errors and guarantee error-free communications through redundancy or retransmission.

Errors in digital communications can take the form of substitution errors in which a symbol is replaced by another symbol, or insertion / deletion errors in which an extra incorrect symbol is inserted into or deleted from a digital message.

Uncorrected errors in digital communications have unpredictable and generally large impact on the information content of the communication.