Unit Delay With Preview Resettable External RV (Obsolete)
Output signal and signal delayed by one sample period, with external RV reset
The Unit Delay With Preview Resettable External RV block is not recommended. This block was removed from the Discrete library in R2016b. In new models, use the Delay block (with parameters set appropriately). Existing models that contain the Unit Delay With Preview Resettable External RV block continue to work for backward compatibility.
Additional Math & Discrete / Additional Discrete (until R2016b)
The Unit Delay With Preview Resettable External RV block supports calculations that
have feedback and depend on the current input. The block can reset its state based on a
The block has three input ports: one for the input signal
for the external reset signal
R, and one for the external reset value
When the reset signal
R is false, the first port outputs the signal
and the second port outputs the signal delayed by one sample period.
When the reset signal
R is true, the first output signal is forced
to equal the reset value
RV. The second output signal is not affected
until one time step later, at which time it is equal to the reset value
RV at the previous time step. The internal Initial
condition has a direct effect on the second output only when the model
starts or when a parent enabled subsystem is reset.
This reset action is vectorized and supports scalar expansion.
Having two outputs is useful for implementing recursive calculations where the result includes the most recent inputs. The second output can feed back into calculations of the block's inputs without causing an algebraic loop. Meanwhile, the first output shows the most up-to-date calculations.
You specify the time between samples with the Sample time
parameter. A setting of
-1 means that the block inherits the
Data Type Support
The Unit Delay With Preview Resettable External RV block accepts signals of the following data types:
The outputs have the same data type as the input
u. For enumerated
signals, the Initial condition must be of the same enumerated type
as the input
For more information, see Data Types Supported by Simulink in the Simulink® documentation.
- Initial condition
Specify the initial output of the simulation.
- Sample time
Specify the time interval between samples. To inherit the sample time, set this parameter to
-1. See Specify Sample Time in the online documentation for more information.
Double | Single | Boolean | Base Integer | Fixed-Point | Enumerated
Specified in the Sample time parameter
Yes, to first output port
No, to second output port
Unit Delay, Unit Delay Enabled (Obsolete), Unit Delay Enabled External IC (Obsolete), Unit Delay Enabled Resettable (Obsolete), Unit Delay Enabled Resettable External IC (Obsolete), Unit Delay External IC (Obsolete), Unit Delay Resettable (Obsolete), Unit Delay Resettable External IC (Obsolete), Unit Delay With Preview Enabled (Obsolete), Unit Delay With Preview Enabled Resettable (Obsolete), Unit Delay With Preview Enabled Resettable External RV (Obsolete), Unit Delay With Preview Resettable (Obsolete)