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Dead Zone

Provide region of zero output

Library

Discontinuities

Description

The Dead Zone block generates zero output within a specified region, called its dead zone. You specify the lower limit (LL) and upper limit (UL) of the dead zone as the Start of dead zone and End of dead zone parameters, respectively. The block output depends on the input (U) and the values for the lower and upper limits:

InputOutput
U >= LL and U <= ULZero
U > ULUUL
U < LLULL

Data Type Support

The Dead Zone block accepts and outputs real signals of the following data types:

  • Floating point

  • Built-in integer

  • Fixed point

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

Parameters and Dialog Box

Start of dead zone

Specify the lower limit of the dead zone. The default is -0.5.

End of dead zone

Specify the upper limit of the dead zone. The default is 0.5.

Saturate on integer overflow
ActionReasons for Taking This ActionWhat Happens for OverflowsExample

Select this check box.

Your model has possible overflow, and you want explicit saturation protection in the generated code.

Overflows saturate to either the minimum or maximum value that the data type can represent.

The maximum value that the int8 (signed, 8-bit integer) data type can represent is 127. Any block operation result greater than this maximum value causes overflow of the 8-bit integer. With the check box selected, the block output saturates at 127. Similarly, the block output saturates at a minimum output value of -128.

Do not select this check box.

You want to optimize efficiency of your generated code.

You want to avoid overspecifying how a block handles out-of-range signals. For more information, see Checking for Signal Range Errors.

Overflows wrap to the appropriate value that is representable by the data type.

The maximum value that the int8 (signed, 8-bit integer) data type can represent is 127. Any block operation result greater than this maximum value causes overflow of the 8-bit integer. With the check box cleared, the software interprets the overflow-causing value as int8, which can produce an unintended result. For example, a block result of 130 (binary 1000 0010) expressed as int8, is -126.

When you select this check box, saturation applies to every internal operation on the block, not just the output or result. Usually, the code generation process can detect when overflow is not possible. In this case, the code generator does not produce saturation code.

Treat as gain when linearizing

The linearization commands in Simulink software treat this block as a gain in state space. Select this check box to cause the commands to treat the gain as 1; otherwise, the commands treat the gain as 0.

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 Specifying Sample Time in the Simulink documentation.

Examples

The following modelmodel uses lower and upper limits of -0.5 and 0.5, with a sine wave as input.

This plot shows the effect of the Dead Zone block on the sine wave. When the input sine wave is between –0.5 and 0.5, the output is zero.

Characteristics

Direct Feedthrough

Yes

Sample Time

Specified in the Sample time parameter

Scalar Expansion

Yes, of parameters

Dimensionalized

Yes

Zero-Crossing Detection

Yes, if enabled

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