MATLAB Programming Fundamentals - MathWorks

Create the audio player object and set the sample rate to the same rate as the input data.

audioOut = audioDeviceWriter('SampleRate',audioIn.SampleRate);

Assemble Components Into System

Connecting System Objects

After you have determined the components you need and have created and configured

your System objects, assemble your system. You use the System objects like other

MATLAB variables and include them in MATLAB code. You can pass MATLAB variables

into and out of System objects.

The main difference between using System objects and using functions is that System

objects use a two-step process. First you create the object and set its parameters and

then, you run the object. Running the object initializes it and controls the data flow and

state management of your system. You typically call a System object within a code loop.

You use the output from an object as the input to another object. For some System

objects, you can use properties of those objects to change the inputs or outputs. To verify

that the appropriate number of inputs and outputs are being used, you can use nargin

and nargout on any System object. For information on all available System object

functions, see “System Object Functions” on page 34-4.

Connect Components in a System

This section shows how to connect the components together to read, filter, and play a file

of audio data. The while loop uses the isDone function to read through the entire file.

while ~isDone(audioIn)

audio = audioIn(); % Read audio source file

y = filtLP(audio); % Filter the data

audioOut(y); % Play the filtered data

end

Run Your System

Run your code by either typing directly at the command line or running a file containing

your program. When you run the code for your system, data is processed through your

objects.

34 System object Usage and Authoring