| Getting Started | |
Observing Channel Errors with the Scope
When you run the model, the Scope block displays the error data. At the end of each five thousand time steps, the scope appears as shown in the following figure. The scope then clears the displayed data and displays the next five thousand data points.
The upper scope shows the channel errors generated by the Binary Symmetric Channel block. The lower scope shows errors that are not corrected by channel coding.
Click the Stop button on the toolbar at the top of the model window to stop the scope.
To zoom in on the scope so that you can see individual errors, first click the middle magnifying glass button at the top left of the Scope window. Then click one of the lines in the lower scope. This zooms in horizontally on the line. Continue clicking the lines in the lower scope until the horizontal scale is fine enough to detect individual errors. A typical example of what you might see is shown in the figure below.
The wider rectangular pulse in the middle of the upper scope represents two 1s. These two errors, which occur in a single code word, are not corrected. This accounts for the uncorrected errors in the lower scope. The narrower rectangular pulse to the right of the upper scope represents a single error, which is corrected.
When you are done observing the errors, selecting Stop from the Simulation menu.
Sending Signal and Error Data to the Workspace explains how to send the error data to the MATLAB workspace for more detailed analysis.
| | Setting Parameters in the Expanded Model | Modeling a Channel with Modulation | |
