Example: Convolution

Construct the model using:

• Buffer block from the Buffers library (in General DSP)
• Convolution block from the Vector Functions library (in Math Functions)
• Sine Wave block from the DSP Sources library
• Time Frame Scope block from the DSP Sinks library
• Window Function block from the Signal Operations library (in General DSP)
• Zero-Order Hold block from the Simulink Discrete library

   1.

Set the Window Function block parameters to generate a length-128 Hamming window.

1. Select Generate window from the Operation pop-up menu.
2. Select Hamming from the Window Type pop-up menu.
3. Enter 128 for Window length.

   2.

Set the Sample time parameter of the Sine Wave block to 0.001.

   3.

Set the Sample time parameter of the Zero-Order Hold block to 0.001*128. This matches the output frame period to the output frame period of the Buffer block.

   4.

Set the Buffer size parameter of the Buffer block to 128.

   5.

In the Time Frame Scope block dialog box, click the Axis properties check box to expose the axis properties panel. Set the following parameter values:

1. Minimum Y-limit = -75
2. Maximum Y-limit = 75

   6.

Set the Stop time to inf in the Parameters dialog box (from the Simulation menu) and start the simulation by selecting Start from the Simulation menu.

The Time Frame Scope window displays the result of the convolution. For input vectors of length M_u and M_v, the Convolution block outputs a vector of length M_u+M_v-1. Here, each result has length 255.

   7.

Stop the simulation at any time by selecting Stop from the Simulation menu.