dsp.SignalSource

Import variable from workspace

Description

The SignalSource object imports a variable from the MATLAB^® workspace.

To import a variable from the MATLAB workspace:

1. Create the dsp.SignalSource 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?

Creation

Syntax

src = dsp.SignalSource

src = dsp.SignalSource(signal,spf)

src = dsp.SignalSource(Name,Value)

Description

src = dsp.SignalSource returns a signal source System object™, src, that outputs the variable, specified by the Signal property, one sample or frame at a time.

src = dsp.SignalSource(signal,spf) returns a signal source object, src, with the Signal property set to signal and the SamplesPerFrame property set to spf.

src = dsp.SignalSource(Name,Value) returns a signal source object, src, 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.

Signal — Variable or expression containing the signal

[1:10]' (default) | vector | matrix

Specify the name of the workspace variable from which to import the signal, or a valid expression specifying the signal.

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

SamplesPerFrame — Number of samples per output frame

1 (default) | positive scalar

Specify the number of samples to buffer into each output frame. This property must be 1 when you specify a 3-D array in the Signal property.

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

SignalEndAction — Action after final signal values are generated

'Set to zero' (default) | 'Hold final value' | 'Cyclic repetition'

Specify the output after all of the specified signal samples have been generated as one of 'Set to zero', 'Hold final value', or 'Cyclic repetition'.

Usage

Syntax

Y = src()

Description

Y = src() outputs one sample or frame of data from each column of the imported signal. The imported signal is the variable or expression you specify for the Signal property of the SignalSource System object, src.

Output Arguments

Y — Output data

scalar | vector | matrix

One sample or one frame of data from each column of the imported signal, returned as a scalar, vector, or matrix. The number of columns in the output signal matches the number of columns in the imported signal, Signal. The number of rows in the output signal matches the value specified in the SamplesPerFrame property.

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

Specific to dsp.SignalSource

isDone

End-of-file status for signal reader object

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

Create Signal Source

Create a signal source to output one sample at a time.

src1 = dsp.SignalSource;
src1.Signal = randn(1024,1);
y1 = zeros(1024,1);
idx = 1;
while(~isDone(src1))
    y1(idx) = src1();
    idx = idx + 1;
end

Create a signal source to output vectors.

src2 = dsp.SignalSource(randn(1024,1),128);
y2 = src2(); % y2 is a 128-by-1 frame of samples

Algorithms

This object implements the algorithm, inputs, and outputs described on the Signal From Workspace block reference page. The object properties correspond to the block parameters, except the System object does not have properties that correspond to the Sample time or Warn when frame size does not evenly divide input length block parameters.

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).

Version History

Introduced in R2012b