Coupling

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Generally, coupling means a mechanical connection between two things. For example railways carriages and wagons are coupled together. Other examples of link coupling include clamps, nipples, and vises. Coupling has other specific meanings in physics, electronics, programming and entertainment.

Table of contents

1 Physics

1.1 See also

2 Electronics

2.2 See also

3 Computer programming

3.3 See also

4 Entertainment

4.4 See also

Physics

In physics, two systems are coupled if they are interacting with each other. Of special interest is the coupling of two (or more) vibratory systems (e.g. pendula or resonant circuits) by means of springss or magnetic fields, etc. Characteristic for a coupled oscilation is the effect of beat.

The concept of coupling is particularly important in the cosmology, in which various forms of matter gradually decouple and recouple between each other.

Coupling is also important for physics for the generation of plasmas. In electrical discharges, the coupling of an exciting field and a medium creates plasmas. The quality of the coupling of an exciting field of given frequency to a charged particle depends on resonance.

Electronics

In telecommunication and electronics, coupling is the desirable or undesirable transfer of energy from one medium, such as a metallic wire or an optical fiber, to another medium, including fortuitous transfer.

Note: Examples of coupling include capacitive (electrostatic) coupling, inductive (magnetic) coupling, conducted (resistive or hard-wire) coupling, and fiber-optic coupling.
Source: This portion is originally from the Federal Standard 1037C and from MIL-STD-188

Computer programming

In computer programming, coupling refers to the degree to which each program module relies on each other module. Coupling can be "high" or "low". Low coupling means that one module does not have to be concerned with the internal implementation of another module. Low coupling is a sign of a well structured computer system. However, in order to achieve maximum efficiency, a highly coupled system is probably needed. In modern computing systems, performance can often be traded for low coupling; the gains in the software development process are greater than the value of the running performance gain.

The types of coupling, in order of lowest to highest coupling, are as follows:

Data coupling - Data coupling is when modules share data through, for example, parameters. Each datum is an elementary piece, and these are the only data which are shared (e.g. passing an integer to a function which computes a square root).
Stamp coupling (Data-structured coupling) - Stamp coupling is when modules share a composite data structure, each module not knowing which part of the data structure will be used by the other (e.g. passing a student record to a function which calculates the student's GPA).
Control coupling - Control coupling is one module controlling the logic of another, by passing it information on what to do (e.g. passing a what-to-do flag).
Common coupling - Common coupling is when two modules share the same global data (e.g. a global variable).
Content coupling - Content coupling is when one module modifies or relies on the internal workings of another module (e.g. accessing local data of another module).

Entertainment

In entertainment, Coupling is a television comedy series from the UK with an extremely short-lived American copy.