Dead Zone

Provide region of zero output

• 

Libraries:
Simulink / Discontinuities
HDL Coder / 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. The block output depends on the input (U) and the values for the lower and upper limits.

Input	Output
U >= LL and U <= UL	Zero
U > UL	U – UL
U < LL	U – LL

Examples

View Dead Zone Output on Sine Wave

This example shows the effect of the Dead Zone block on a sine wave. The model uses a dead zone lower limit of -0.5 and an upper limit of 0.5. Set these values using the parameters Start of Dead Zone and End of Dead Zone.

Ports

Input

Port_1 — Input signal

scalar | vector

Input signal to the dead-zone algorithm.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | fixed point

Output

Port_1 — Output signal

scalar | vector

Output signal after the dead-zone algorithm is applied to the input signal.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | fixed point

Parameters

Start of dead zone — Specify the lower bound of the dead zone

'-0.5' (default) | scalar | vector

Specify dead zone lower limit. Set the value for Start of dead zone less than or equal to End of dead zone. When the input value is less than Start of dead zone, then the block shifts the output value down by the Start of dead zone value.

Programmatic Use

Block Parameter: LowerValue

Type: character vector

Value: scalar or vector less than or equal to UpperValue.

Default: '-0.5'

End of dead zone — Specify the upper limit of the dead zone

'0.5' (default) | scalar | vector

Specify dead zone upper limit. Set the value for End of dead zone greater than or equal to Start of dead zone. When the input value is greater than End of dead zone, then the block shifts the output value down by the End of dead zone value.

Programmatic Use

Block Parameter: UpperValue

Type: character vector

Value: scalar or vector greater than or equal to LowerValue.

Default: '0.5'

Saturate on integer overflow — Method of overflow action

on (default) | off

Specify whether overflows saturate or wrap.

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

• off — Overflows wrap to the appropriate value that the data type can represent.

For example, the maximum value that the signed 8-bit integer int8 can represent is 127. Any block operation result greater than this maximum value causes overflow of the 8-bit integer.

• With this parameter selected, the block output saturates at 127. Similarly, the block output saturates at a minimum output value of -128.

• With this parameter 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.

Tips

• Consider selecting this parameter when your model has a possible overflow and you want explicit saturation protection in the generated code.

• Consider clearing this parameter when you want to optimize efficiency of your generated code. Clearing this parameter also helps you to avoid overspecifying how a block handles out-of-range signals. For more information, see Troubleshoot Signal Range Errors.

• When you select this parameter, saturation applies to every internal operation on the block, not just the output or result.

• In general, the code generation process can detect when overflow is not possible. In this case, the code generator does not produce saturation code.

Programmatic Use

To set the block parameter value programmatically, use the set_param function.

Parameter:	SaturateOnIntegerOverflow
Values:	'on' (default) | 'off'

Treat as gain when linearizing — Specify the gain value

on (default) | off

The linearization commands in Simulink^® software treat this block as a gain in state space. Select this parameter to cause the commands to treat the gain as 1. Clear this parameter to have the commands treat the gain as 0.

Programmatic Use

Block Parameter: LinearizeAsGain

Type: character vector

Value: 'off' | 'on'

Default: 'on'

Enable zero-crossing detection — Enable zero-crossing detection

on (default) | off

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

Programmatic Use

Block Parameter: ZeroCross

Type: character vector | string

Values: 'off' | 'on'

Default: 'on'

Sample time (-1 for inherited) — Interval between samples

-1 (default) | scalar | vector

Specify the time interval between samples. To inherit the sample time, set this parameter to -1. For more information, see Specify Sample Time.

Dependencies

This parameter is visible only if you set it to a value other than -1. To learn more, see Blocks for Which Sample Time Is Not Recommended.

Programmatic Use

To set the block parameter value programmatically, use the set_param function.

Parameter:	SampleTime
Values:	"-1" (default) | scalar or vector in quotes

Block Characteristics

Data Types	double | fixed point | integer | single
Direct Feedthrough	yes
Multidimensional Signals	no
Variable-Size Signals	no
Zero-Crossing Detection	yes

More About

Model Coverage

If you have a Simulink Coverage™ license, the Dead Zone block receives decision coverage. Simulink Coverage reports decision coverage based on the values of these parameters:

• Start of dead zone

• End of dead zone

The Start of dead zone parameter specifies the lower limit of the dead zone, and decision coverage measures:

• The number of time steps that the block input is greater than or equal to the lower limit, which indicates a true decision

• The number of time steps that the block input is less than the lower limit, which indicates a false decision

The End of dead zone parameter specifies the upper limit of the dead zone, and decision coverage measures:

• The number of time steps that the block input is greater than the upper limit, which indicates a true decision

• The number of time steps that the block input is less than or equal to the upper limit, which indicates a false decision

The Dead Zone block uses logical short circuiting, and ignores the value of the Treat Simulink logic blocks as short-circuited (Simulink Coverage) parameter. When the upper limit is true, the block does not evaluate the lower limit decision for that time step. Therefore, the total number of lower limit decisions is equal to the number of time steps where the upper limit decision is false.

If you select the Saturation on integer overflow (Simulink Coverage) parameter, the Dead Zone block receives saturation on integer overflow coverage. For more information, see Saturate on Integer Overflow Coverage (Simulink Coverage).

The Dead Zone block compares the input signal with an upper and lower limit value. If you select the Relational boundary (Simulink Coverage) parameter, the Dead Zone block receives relational boundary coverage. For more information, see Relational Boundary Coverage (Simulink Coverage).

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

HDL Code Generation

Generate VHDL, Verilog and SystemVerilog code for FPGA and ASIC designs using HDL Coder™.

HDL Coder™ provides additional configuration options that affect HDL implementation and synthesized logic.

HDL Architecture

This block has one default HDL architecture.

HDL Block Properties

ConstrainedOutputPipeline	Number of registers to place at the outputs by moving existing delays within your design. Distributed pipelining does not redistribute these registers. The default is 0. For more details, see ConstrainedOutputPipeline (HDL Coder).
InputPipeline	Number of input pipeline stages to insert in the generated code. Distributed pipelining and constrained output pipelining can move these registers. The default is 0. For more details, see InputPipeline (HDL Coder).
OutputPipeline	Number of output pipeline stages to insert in the generated code. Distributed pipelining and constrained output pipelining can move these registers. The default is 0. For more details, see OutputPipeline (HDL Coder).

Fixed-Point Conversion
Design and simulate fixed-point systems using Fixed-Point Designer™.

Version History

Introduced before R2006a