block diagram

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block diagram

[′bläk ‚dī·ə‚gram]
A diagram in which the essential units of any system are drawn in the form of rectangles or blocks and their relation to each other is indicated by appropriate connecting lines.

Block diagram

A convenient graphical representation of input-output behavior of a system, where the signal into the block represents the input and the signal out of the block represents the output. The flow of information (the signal) is unidirectional from the input to the output. The primary use of the block diagram is to portray the interrelationship of distinct parts of the system.

A block diagram consists of two basic functional units that represent system operations. The individual block symbols portray the dynamic relations between the input and output signals. The second type of unit, called a summing point, is represented by a circle with arrows feeding into it. The operation that results is a linear combination of incoming signals to generate the output signal. The sign appearing alongside each input to the summing point indicates the sign of that signal as it appears in the output.

Block diagrams are widely used in all fields of engineering, management science, criminal justice, economics, and the physical sciences for the modeling and analysis of systems. In modeling a system, some parameters are first defined and equations governing system behavior are obtained. A block diagram is constructed, and the transfer function for the whole system is determined.

If a system has two or more input variables and two or more output variables, simultaneous equations for the output variables can be written. In general, when the number of inputs and outputs is large, the simultaneous equations are written in matrix form.

Block diagrams can be used to portray nonlinear as well as linear systems, such as a cascade containing a nonlinear amplifier and a motor. See Computer programming, Gain, Systems engineering

block diagram

A chart that contains squares and rectangles connected with arrows to depict hardware and software interconnections. For program flow charts, information system flow charts, circuit diagrams and communications networks, more elaborate graphical representations are usually used.

Block Diagram of a Computer