Gain (Using Simulink)

Multiply block input.

Library

Math

Description

The Gain block generates its output by multiplying its input by a specified constant, variable, or expression.You can enter the gain as a numeric value, or as a variable or expression. To multiply the input by a matrix, use the Matrix Gain block (see Matrix Gain).

The Gain block icon displays the value entered in the Gain parameter field if the block is large enough. If the gain is specified as a variable, the block displays the variable name, although if the variable is specified in parentheses, the block evaluates the variable each time the block is redrawn and displays its value. If the Gain parameter value is too long to be displayed in the block, the string -K- is displayed.

To modify the gain during a simulation using a slider control (see Slider Gain).

Data Type Support

A Gain block accepts a real- or complex-valued scalar or vector of any data type except boolean and outputs a signal of the same data type as its input. The elements of an input vector must be of the same type. A Gain blocks Gain parameter can also be a real- or complex-valued scalar or vector of any data type. A Gain block observes the following type rules:

If the input is real and the gain is complex, the output is complex.
If the gain parameter's data type differs from the input signal's data type and the input data type can represent the gain, Simulink converts the gain to the input type before computing the output. Otherwise, Simulink halts the simulation and signals an error. For example, if the input data type is uint8 and the gain is -1, an error results. If typecasting the gain parameter to the input data type results in a loss of precision, Simulink issues a warning and continues the simulation.
If the output data type is an integer type and the gain block's Saturate on integer overflow option is selected, the block saturates if the output exceeds the maximum value representable by the block's output data type. In other words, the block outputs one plus the maximum positive or minimum negative value representable by the output data type. For example, if the output type is int8, the actual output is 128 if the computed output is greater than 128 and -128 if the computed output is less than -128.

Parameters and Dialog Box

Gain

The gain, specified as a scalar, vector, variable name, or expression. The default is 1. If not specified, the data type of the Gain parameter is double.

Saturate on integer overflow

If selected, this option causes the output of the Gain block to saturate on integer overflow. In particular, if the output data type is an integer type, the block output is the maximum value representable by the output type or the computed output, whichever is smaller in the absolute sense. If the option is not selected, Simulink takes that action specified by the Data overflow event option on the Diagnostics page of the Simulation Parameters dialog box (see "The Diagnostics Page").

Characteristics


Direct Feedthrough	Yes
Sample Time	Inherited from driving block
Scalar Expansion	Of input and Gain parameter
States	0
Vectorized	Yes
Zero Crossing	No

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