what is coupling

Coupling is when two or more circuits form a network. If the current or voltage in one of the circuits changes, it can affect other circuits to undergo similar changes. This kind of network is called a coupling circuit. , the function of coupling is to transfer the energy of a certain circuit to other circuits.

1. Introduction:

Coupling is two or more circuits When forming a network, if the current or voltage in one circuit changes, it can affect other circuits to undergo similar changes. This type of network is called a coupling circuit. The function of coupling is to transfer the energy of one circuit to other circuits. Go in.

Before we get into the term coupling, let’s look at an example of a stereo record player amplifier circuit. As can be seen from the figure below, each speaker is directly connected to the amplifier. Without the amplifier, there will be no sound. At the same time, the amplifier and the stereo record player are also directly connected.

However, the left and right speakers are not directly connected. We can unplug a speaker at will without affecting other devices. It can be seen that the coupling between the speakers and other devices is extremely weak. The coupling between them is very loose, that is, the modules can be separated by simply unplugging the plug, without using a soldering iron to desolder the wires or solder tabs on the printed board. On the contrary, if we connect the modules with wire welding, the coupling between them will be tighter (tighter coupling).

In electronic circuits, when several circuits form a network with a common impedance, changes in voltage or current in one circuit can cause corresponding changes in other circuits. According to the nature of the common impedance, it can be divided into resistive coupling, inductive coupling, capacitive coupling and resistor-capacitive coupling.

2. Main classification

System coupling originated from physics. In physics, coupling refers to a measure that two entities depend on each other. It is divided into The following:

Non-direct coupling

There is no direct relationship between the two modules. The connection between them is completely realized through the control and calling of the main module. of.

Data Coupling

When one module accesses another module, they are exchanged through simple data parameters (not control parameters, public data structures or external variables) Input and output information.

Mark coupling

A group of modules pass record information through parameter tables. This record is a substructure of a certain data structure, not a simple variable.

Control coupling

If a module obviously controls the selection of the function of another module by transmitting control information such as switches, flags, names, etc., it is control coupling .

External coupling

A group of modules all access the same global simple variable instead of the same global data structure, and the information about the global variable is not passed through the parameter table, it is called It's called external coupling.

Public Coupling

If a group of modules all access the same common data environment, the coupling between them is called public coupling. The public data environment can be the communication area shared by the global data structure, the public coverage area of ​​the memory, etc.

Content coupling

If the following situations occur, content coupling occurs between two modules:

①One module directly accesses another module internal data;

②One module does not go to the inside of another module through the normal entrance;

③The two modules have a part of the program code overlap (only possible in assembly language);

④A module has multiple entrances.

3. Strength

The strength of coupling depends on whether the division of modules is reasonable and the complexity of the interface between modules. Therefore, when dividing modules, you should try your best to:

① Eliminate unnecessary connections between modules;

② Reduce the number of essential connections between modules;

③The closeness of the connection between loose modules.

By doing this, you can get module divisions that are relatively weakly coupled and loosely coupled to each other.

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