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Detect Rise Positive

Detect rising edge when signal value increases to strictly positive value, and its previous value was nonpositive

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  • Detect Rise Positive block

Libraries:
Simulink / Logic and Bit Operations

Description

The Detect Rise Positive block detects a rising edge by determining if the input is strictly positive, and its previous value was nonpositive.

  • The output is true (equal to 1) when the input signal is greater than zero, and the previous value was less than or equal to zero.

  • The output is false (equal to 0) when the input is negative or zero, or if the input is positive, the previous value was also positive.

This block supports only discrete sample times.

Examples

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Open Model

This example shows how to detect the rising edge of a signal using the Detect Rise Nonnegative and Detect Rise Positive blocks.

With a fixed-step size of 0.25, this example illustrates the difference between the Detect Rise Nonnegative and Detect Rise Positive blocks. The Detect Rise Nonnegative block outputs true (1) at t=1 because the input signal increased from a negative value to a nonnegative value (0). The Detect Rise Positive block outputs true (1) at t=1.25 because the input signal increased from a nonpositive value (0) to a strictly positive value.

Ports

Input

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Input signal, specified as a scalar, vector, or matrix.

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

Output

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Output signal that detects a rising edge whenever the input is strictly positive, and its previous value was nonpositive. The output can be a scalar, vector, or matrix.

  • The output is true (equal to 1) when the input signal is greater than zero, and the previous value was less than or equal to zero.

  • The output is false (equal to 0) when the input is negative or zero, or if the input is positive, the previous value was also positive.

Data Types: uint8 | Boolean

Parameters

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Set the initial condition of the Boolean expression U/z > 0.

Programmatic Use

Block Parameter: vinit
Type: character vector
Values: scalar | vector | matrix
Default: '0'

Specify whether the block performs sample- or frame-based processing:

  • Columns as channels (frame based) — Treat each column of the input as a separate channel (frame-based processing).

    Note

    Frame-based processing requires a DSP System Toolbox™ license.

    For more information, see Sample- and Frame-Based Concepts (DSP System Toolbox).

  • Elements as channels (sample based) — Treat each element of the input as a separate channel (sample-based processing).

Use Input processing to specify whether the block performs sample- or frame-based processing. For more information about these two processing modes, see Sample- and Frame-Based Concepts (DSP System Toolbox).

Programmatic Use

Block Parameter: InputProcessing
Type: character vector
Values: 'Columns as channels (frame based)' | 'Elements as channels (sample based)'
Default: 'Elements as channels (sample based)'

Specify the output data type as boolean or uint8.

Programmatic Use

Block Parameter: OutDataTypeStr
Type: character vector
Values: 'boolean' | 'uint8'
Default: 'boolean'

Block Characteristics

Data Types

Boolean | double | fixed point | integer | single

Direct Feedthrough

yes

Multidimensional Signals

yes

Variable-Size Signals

yes

Zero-Crossing Detection

no

Extended Capabilities

PLC Code Generation
Generate Structured Text code using Simulink® PLC Coder™.

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

Version History

Introduced before R2006a

See Also

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