Equivocation (information theory)

The term refers to equivocation in the context of information theory that information which is lost during transmission over a channel between an information source (sender ) and an information sink (receiver). The concept of information in this context is to be understood as information and goes on Claude Shannon back who laid the theoretical foundations for this in the 1940s.

The abstract concept of an information channel can be in practical implementations over the place, such as a radio link between two points, or over time, for example in the form of a data memory extend.

Definition

The mathematical definition of the information content is closely linked to the entropy, the random variable describes the set of all possible symbols in the transmission channel. An information source sends now, as shown in the right figure, receives over a channel for which information sink. can an introduced on channel misinformation or according to the equivocation occurring at the channel be different according to. The notation stands for the conditional entropy with the two random variables.

As conditional entropy can be the equivocation, the mutual information between source and sink, expressed as:

As a probability function the equivocation expressed with the logarithm to the base 2 as:

Swell

• Jürgen Lindner: information transfer. Springer Verlag, Berlin Heidelberg 2005, ISBN 3-540-21400-3, p 313

• Information Theory