DSP Blockset

Importing a Frame-Based Signal with
the Signal From Workspace Block

The Signal From Workspace block generates a frame-based multichannel signal when the variable (or expression) in the Signal parameter is a matrix, and the Samples per frame parameter specifies a value M greater than 1. Beginning with the first M rows of the matrix, the block releases M rows of the matrix (i.e., one frame from each channel) to the output every M*T_s seconds. Therefore, if the Signal parameter specifies a W-by-N workspace matrix, the output of the Signal From Workspace block is an M-by-N matrix representing N channels.

The figure below illustrates this for a 6-by-4 workspace matrix, A, and a frame size of 2.

As the figure above suggests, the output of the Signal From Workspace block can only be a valid frame-based signal (having N independent channels) if the W-by-N workspace matrix A in fact represents N independent channels. In other words, the workspace matrix must be oriented so as to have the independent channels as its columns.

Note    Although independent channels are generally represented as columns, a single-channel signal can be represented in the workspace as either a column vector or row vector. The output from the Signal From Workspace block is a column vector in both cases.

When the block has output all of the rows available in the specified variable, it can start again at the beginning of the signal, or simply repeat the final value (or generate zeros) until the end of the simulation. This behavior is controlled by the Form output after final data value by parameter. See the Signal From Workspace block reference page for more information.

The following example illustrates how the Signal From Workspace block is used to import a frame-based multichannel signal into a model.

Importing a Multichannel Frame-Based Signal

Example: Importing a Frame-Based Signal