DSP Blockset

Example: Creating Signals with the Sine Wave Block

The Sine Wave block dialog box contains the following key parameters.

• Amplitude
• Frequency
• Phase offset
• Sample time
• Samples per frame

In the model below, a Sine Wave block generates a frame-based (multichannel) matrix containing three independent signals:

• Sine wave of amplitude 1 and frequency 100 Hz
• Sine wave of amplitude 3 and frequency 250 Hz
• Sine wave of amplitude 2 and frequency 500 Hz

Each channel has a frame size of 64 samples. The three signals are summed point-by-point by a Matrix Sum block, and exported to the workspace.

To build the model, set the Sum along parameter of the Matrix Sum block to Rows, and make the following parameter settings in the Sine Wave block:

• Set Amplitude to [1 3 2]. This specifies the amplitudes for three independent sinusoids (and therefore dictates a three-column output).
• Set Frequency to [100 250 500]. This specifies the frequency for each of the output sinusoids.
• Set Sample time to 1/5000. (This is ten times the highest sinusoid frequency, and so satisfies the Nyquist criterion.)
• Set Samples per frame to 64. This specifies a frame size of 64 for all sinusoids (and therefore dictates a 64-row output).

After running the model, you can look at a portion of the resulting summed sinusoid by typing

• plot(yout(1:100))
  

at the command line.

See Multichannel Signals for more information about the representation of sample-based and frame-based data.

Creating Signals Using Signal Generator Blocks

Creating Signals Using the Signal From Workspace Block