Sample and Hold

Sample and hold input signal

  • Library:
  • DSP System Toolbox / Signal Operations

    DSP System Toolbox HDL Support / Signal Operations

Description

The Sample and Hold block acquires the input at the signal port whenever it receives a trigger event at the trigger port (marked by ). The block then holds the output at the acquired input value until the next triggering event occurs.

Ports

Input

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The signal port can accept data in the form of a scalar, vector, or matrix.

Dependencies

This port is named In<Lo> when you select the Latch (buffer) input parameter.

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

The trigger input must be a sample-based scalar with sample rate equal to the input frame rate at the signal port. You specify the trigger event using the Trigger type parameter.

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

Output

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Sample and hold output, returned as a scalar, vector, or a matrix. The block acquires input at the signal port whenever it receives a trigger event at the trigger port. The block then holds the acquired data until the next triggering event occurs.

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

Parameters

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The type of event that triggers the block to acquire the input signal:

  • Rising edge –– The trigger input rises from a negative value or zero to a positive value.

  • Falling edge –– The trigger input falls from a positive value or zero to a negative value.

  • Either edge –– The trigger input either rises from a negative value or zero to a positive value or falls from a positive value or zero to a negative value.

Specify the block's output before the first trigger event using the Initial condition parameter. When the acquired input is an M-by-N matrix, the Initial condition can be an M-by-N matrix or a scalar repeated across all elements of the matrix. When the input is a length-M unoriented vector, the Initial condition can be a length-M row or column vector, or a scalar to be repeated across all elements of the vector.

If you select the Latch (buffer) input check box, the block outputs the value of the input from the previous time step until the next triggering event occurs. To use this block in a loop, select this check box.

Block Characteristics

Data Types

Boolean | double | fixed point | integer | single

Direct Feedthrough

no

Multidimensional Signals

no

Variable-Size Signals

no

Zero-Crossing Detection

no

Extended Capabilities

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

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

See Also

Blocks

Introduced before R2006a