Discrete Derivative
Calculates the discrete time derivative.
Description
Block Discrete Derivative calculates the discrete time derivative with an arbitrary coefficient using the formula:
,
where
-
and are input and output values of the block at the current time step, respectively;
-
- input values of the block at the previous time step;
-
- scaling factor set using the parameters Gain value;
-
- size of discrete modelling step, which should be fixed.
| Do not use this block in subsystems with non-periodic starts, such as Function-Call subsystems. This configuration gives inaccurate results. |
Ports
Input
#
IN_1
—
input signal
scalar | vector | matrix
Details
An input signal specified as a scalar, vector or matrix.
| Data types |
|
| Complex numbers support |
Yes |
Output
#
OUT_1
—
scaled discrete-time derivative
scalar | vector | matrix
Details
A scaled derivative over discrete time in the form of a scalar, vector or matrix.
The output signal data type is specified by the parameters Output data type.
| Data types |
|
| Complex numbers support |
Yes |
Parameters
Main
#
Gain value —
scaling factor
Scalar / array of real numbers
Details
The scaling factor applied to the calculated derivative.
| Default value |
|
| Program usage name |
|
| Tunable |
No |
| Evaluatable |
Yes |
#
Initial condition for previous weighted input K*u/Ts —
initial condition
Scalar / array of real and/or complex numbers
Details
Initial condition for the previous scaled input value.
| Default value |
|
| Program usage name |
|
| Tunable |
Yes |
| Evaluatable |
Yes |
Signal Attributes
#
Output data type —
output data type
Inherit: auto | Float64 | Float32 | Int8 | UInt8 | Int16 | UInt16 | Int32 | UInt32 | Int64 | UInt64 | Int128 | UInt128 | Fixed-point
Details
Specify the type of output data. You can specify:
-
Data type inheritance
Inherit: auto. -
Embedded data type, e.g.,
Float32. -
A fictionalised point data type
Fixed-point.
| Values |
|
| Default value |
|
| Program usage name |
|
| Tunable |
No |
| Evaluatable |
No |
#
Output fixed-point type —
fixed-point output data type
Data type
Details
Specify the type of fixed-point output data.
Dependencies
This parameter appears when the parameters are set to Output data type is set to Fixed-point.
| Default value |
|
| Program usage name |
|
| Tunable |
No |
| Evaluatable |
Yes |
#
Integer rounding mode —
rounding mode for fixed-point operations
Ceiling | Convergent | Floor | Nearest | Round | Zero
Details
Select the rounding mode for fixed-point operations. You can select:
-
Floor- rounds both positive and negative numbers downwards (towards negative infinity). -
Ceiling- rounds both positive and negative numbers upwards (towards positive infinity). -
Convergent- rounds the number to the nearest representable value. If the fractional part of a number ends in 5, the number is rounded to the nearest even integer. -
Nearest- rounds the number to the nearest representable value. If the fractional part of the number ends in 5, the number is rounded upwards (towards positive infinity). -
Round- rounds the number to the nearest representable value. If the fractional part of a number ends in 5, positive numbers are rounded upwards (towards positive infinity) and negative numbers are rounded downwards (towards negative infinity).
-
Zero- rounds the number towards zero.
The block parameters are always rounded to the nearest representable value.
| Values |
|
| Default value |
|
| Program usage name |
|
| Tunable |
No |
| Evaluatable |
No |
#
Saturate to max or min when overflows occur —
overflow action method
Logical
Details
When this checkbox is selected, a value that exceeds the type boundaries is reset to the maximum or minimum value that the selected data type can represent. Otherwise, the overflow is carried over.
When this checkbox is selected, saturation is applied to all internal operations in the block, not just the output data or result.
| Default value |
|
| Program usage name |
|
| Tunable |
No |
| Evaluatable |
No |