dsp.VariableIntegerDelay

Delay input by time-varying integer number of sample periods

Description

Note

The DirectFeedthrough property will be removed in a future release. Delete all instances of this property in your MATLAB^® code. For more details, see Compatibility Considerations.

The dsp.VariableIntegerDelay System object™ delays input by time-varying integer number of sample periods.

To delay the input by a time-varying integer number of sample periods:

1. Create the dsp.VariableIntegerDelay object and set its properties.

2. Call the object with arguments, as if it were a function.

To learn more about how System objects work, see What Are System Objects? (MATLAB).

Creation

Syntax

vid = dsp.VariableIntegerDelay

vid = dsp.VariableIntegerDelay(Name,Value)

Description

vid = dsp.VariableIntegerDelay returns a variable integer delay System object, vid, that delays discrete-time input by a time-varying integer number of sample periods.

vid = dsp.VariableIntegerDelay(Name,Value) returns a variable integer delay System object with each specified property set to the specified value.

Properties

Unless otherwise indicated, properties are nontunable, which means you cannot change their values after calling the object. Objects lock when you call them, and the release function unlocks them.

If a property is tunable, you can change its value at any time.

For more information on changing property values, see System Design in MATLAB Using System Objects (MATLAB).

MaximumDelay — Maximum delay

100 (default) | positive integer scalar

Specify the maximum delay the object can produce for any sample. The object clips input delay values greater than the MaximumDelay to the MaximumDelay.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

InitialConditions — Initial values in memory

0 (default) | scalar | 1-by-N-by-D array

Specify the values with which the object's memory is initialized. The dimensions of this property can vary depending on whether you want fixed or time-varying initial conditions.

For an M-by-N frame-based input matrix U, you can set the InitialConditions property as follows:

• To specify fixed initial conditions, set the InitialConditions property to a scalar value. The object initializes every sample of every channel in memory using the value you specify.

• To specify different time-varying initial conditions for each channel, set the InitialConditions property to an array of size 1-by-N-by-D, where D is the value of the MaximumDelay property.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

DirectFeedthrough — Allow direct feedthrough

true (default) | false

When you set this property to true, the object allows direct feedthrough. When you set this property to false, the object increases the minimum possible delay by one.

Usage

Syntax

vidOut = vid(input,d)

Description

vidOut = vid(input,d) delays the input by d samples, where d should be less than or equal to the value specified in the MaximumDelay property and greater than or equal to 0. Delay values outside this range are clipped appropriately and non-integer delays are rounded to the nearest integer values. Each column of the input is treated as an independent channel

Input Arguments

input — Data input

vector | matrix

Data input, specified as a vector or matrix.

This object supports variable-size input signal. That is, you can change the input frame size (number of rows) even after calling the algorithm. However, the number of channels (number of columns) must remain constant.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | fi
Complex Number Support: Yes

d — Delay input

scalar | vector | matrix

Delay input, specified as a scalar, vector, or matrix. The delay is an integer value.

For an M-by-1 or a 1-by-N data input vector, the delay can be a:

• Scalar

• Vector –– The length and the orientation of the delay vector match the length and the orientation of the data input.

For an M-by-N matrix data input, the delay can be a:

• Column vector –– The length of the vector is M.

• Row vector –– The length of the vector is N.

• Matrix –– Delay must be an M-by-N matrix.

The dimensions of the delay signal can change according to the supported dimensions listed in the table. The table also shows how delay signal is applied to the input signal.

Data Input	Delay Input	Output	Effect of Delay Input on Data Input
M-by-1 (one channel with frame size equal to M)	scalar	M-by-1	One delay value applied to the input channel
M-by-1 (one channel with frame size equal to M)	M-by-1	M-by-1	Delay value varies within the frame from sample to sample
1-by-N (N channels with frame size equal to 1)	scalar	1-by-N	One delay value applied to all the N channels
1-by-N (N channels with frame size equal to 1)	1-by-N	1-by-N	Unique delay value for each input channel
M-by-N (N channels with frame size equal to M)	scalar	M-by-N	One delay value applied to all input channels
M-by-N (N channels with frame size equal to M)	1-by-N	M-by-N	Unique delay value for each input channel
M-by-N (N channels with frame size equal to M)	M-by-1	M-by-N	Delay value varies within the frame from sample to sample. Same set of delay values for all channels.
M-by-N (N channels with frame size equal to M)	M-by-N	M-by-N	Unique delay value for each element in the matrix

Example: [2 3 4 5]

Example: [2;3;4;5]

Example: [5]

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

Output Arguments

vidOut — Delayed output

vector | matrix

Delayed output, returned as a vector or matrix. The size, data type, and complexity of the output match the size, data type, and complexity of the data input, input.

The table shows how the data input and delay input dimensions affect the output dimensions:

Data Input	Delay Input	Output	Effect of Delay Input on Data Input
M-by-1 (one channel with frame size equal to M)	scalar	M-by-1	One delay value applied to the input channel
M-by-1 (one channel with frame size equal to M)	M-by-1	M-by-1	Delay value varies within the frame from sample to sample
1-by-N (N channels with frame size equal to 1)	scalar	1-by-N	One delay value applied to all the N channels
1-by-N (N channels with frame size equal to 1)	1-by-N	1-by-N	Unique delay value for each input channel
M-by-N (N channels with frame size equal to M)	scalar	M-by-N	One delay value applied to all input channels
M-by-N (N channels with frame size equal to M)	1-by-N	M-by-N	Unique delay value for each input channel
M-by-N (N channels with frame size equal to M)	M-by-1	M-by-N	Delay value varies within the frame from sample to sample. Same set of delay values for all channels.
M-by-N (N channels with frame size equal to M)	M-by-N	M-by-N	Unique delay value for each element in the matrix

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | fi
Complex Number Support: Yes

Object Functions

To use an object function, specify the System object as the first input argument. For example, to release system resources of a System object named obj, use this syntax:

release(obj)

Common to All System Objects

step	Run System object algorithm
release	Release resources and allow changes to System object property values and input characteristics
reset	Reset internal states of System object

Examples

Delay a Signal with VariableIntegerDelay Object

Note: If you are using R2016a or an earlier release, replace each call to the object with the equivalent step syntax. For example, obj(x) becomes step(obj,x).

Delay a signal by a varying number of integer sample periods.

vid = dsp.VariableIntegerDelay;

yout = zeros(100,1);
x    = (1:100).';

for k=1:10
   range       = (k-1)*10+1:k*10;
   yout(range) = vid(x(range),k);
end

stem(x,'b')
hold on; 
stem(yout,'r')
legend('Original Signal', 'Variable Integer Delayed Signal')

Algorithms

This object implements the algorithm, inputs, and outputs described on the Variable Integer Delay block reference page. The object properties correspond to the block properties, except:

When you set the DirectFeedthrough property of the System object to true, the object allows direct feedthrough. This behavior is different from the way the block behaves when you select the corresponding Disable direct feedthrough by increasing minimum possible delay by one check box on the block dialog. When you enable this block parameter, the block does not allow direct feedthrough.

Compatibility Considerations

Removal of DirectFeedthrough Property

Warns starting in R2018a

The DirectFeedthrough property will be removed in a future release. Trying to modify this property warns. Make sure you remove all references to this property from your MATLAB code. The dsp.VariableIntegerDelay object now operates in direct feedthrough mode by default.

Extended Capabilities

C/C++ Code Generation

Generate C and C++ code using MATLAB® Coder™.

Usage notes and limitations:

See System Objects in MATLAB Code Generation (MATLAB Coder).