Sign - Indicate sign of input

Library

Math Operations

Description

Block Behavior for Real Inputs

For real inputs, the Sign block outputs the sign of the input:

Input	Output
Greater than zero	1
Equal to zero	0
Less than zero	–1

For vector and matrix inputs, the block outputs a vector or matrix where each element is the sign of the corresponding input element, as shown in this example:

Block Behavior for Complex Inputs

When the input u is a complex scalar, the block output matches the MATLAB result for:

sign(u) = u./ abs(u)

When an element of a vector or matrix input is complex, the block uses the same formula that applies to scalar input, as shown in this example:

Data Type Support

The Sign block supports real inputs of the following data types:

• Floating point

• Built-in integer

• Fixed point

• Boolean

The block supports complex inputs only for floating-point data types, double and single. The output uses the same data type as the input.

For more information, see Data Types Supported by Simulink in the Simulink documentation.

Parameters and Dialog Box

Enable zero-crossing detection

Select to enable zero-crossing detection. For more information, see Zero-Crossing Detection.

Sample time (-1 for inherited)

Specify the time interval between samples. To inherit the sample time, set this parameter to -1. See How to Specify the Sample Time in the Simulink documentation for more information.

Examples

The following Simulink demos show how to use the Sign block:

• sldemo_fuelsys (in the Engine Gas Dynamics/Throttle & Manifold/Throttle subsystem)

• sldemo_hardstop

Characteristics

Direct Feedthrough	Yes
Sample Time	Specified in the Sample time parameter
Scalar Expansion	N/A
Dimensionalized	Yes
Multidimensionalized	No
Zero-Crossing Detection	Yes, if enabled

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