Using Simulink

Unit Delay

Delay a signal one sample period.

Library

Discrete

Description

The Unit Delay block delays and holds its input signal by one sampling interval. If the input to the block is a vector, all elements of the vector are delayed by the same sample delay. This block is equivalent to the z^-1 discrete-time operator.

If an undelayed sample-and-hold function is desired, use a Zero-Order Hold block, or if a delay of greater than one unit is desired, use a Discrete Transfer Fcn block. (See the description of the Transport Delay block for an example that uses the Unit Delay block.)

Data Type Support

A Unit block accepts real or complex signals of any data type, including user-defined types. If the data type of the input signal is user-defined, the initial condition must be 0.

Parameters and Dialog Box

Initial condition

The block output for the first simulation period, during which the output of the Unit Delay block is undefined. Careful selection of this parameter can minimize unwanted output behavior during this time. The default is 0.

Sample time

The time interval between samples. The default is 1.

Characteristics

Direct Feedthrough	No
Sample Time	Discrete
Scalar Expansion	Of the Initial condition parameter or the input
States	Inherited from driving block or parameters
Dimensionalized	Yes
Zero Crossing	No

Uniform Random Number

Variable Transport Delay