Discrete Derivative (Simulink Reference)

Compute a discrete time derivative

Library

Discrete

Description

The Discrete Derivative block computes a discrete time derivative by subtracting the input value at the previous time step from the current value, and dividing by the sample time.

Data Type Support

The Discrete Derivative block supports all Simulink data types, including fixed-point data types.

For a discussion on the data types supported by Simulink, refer to Data Types Supported by Simulink in the Using Simulink documentation.

Parameters and Dialog Box

The Main pane of the Discrete Derivative block dialog appears as follows:

Gain value: Specify the weight by which the sample time is multiplied.
Initial condition for previous weighted input K*u/Ts: Set the initial condition for the previous scaled input.

The Signal data types pane of the Discrete Derivative block dialog box appears as follows:

Output data type and scaling: Specify the output data type and scaling via the dialog box, or inherit the data type and scaling from the driving block or by backpropagation. If you choose Specify via dialog, the Output data type and Output scaling parameters appear.
Output data type: Set the output data type. This parameter is only visible if you select Specify via dialog for the Output data type and scaling parameter.
Output scaling: Set the output scaling using either binary point-only or [Slope Bias] scaling. This parameter is only visible if you select Specify via dialog for the Output data type and scaling parameter.
Lock output scaling so autoscaling tool can't change it: If you select this check box, the output scaling is locked.
Round toward: Select the rounding mode for fixed-point operations.
Saturate to max or min when overflows occur: If selected, fixed-point overflows saturate.

Characteristics

Direct Feedthrough
Yes

Scalar Expansion
Yes, of inputs and gain

Direct Feedthrough	Yes
Scalar Expansion	Yes, of inputs and gain

See Also

Derivative

Direct Lookup Table (n-D) Discrete Filter