User`s guide
3 Working with Signals
3-86
A first step in improving performance is to analyze your model, and eliminate
or simplify elements that are adding excessively to the computational load.
Such elements might include scope displays and data logging blocks that you
had put in place for debugging purposes and no longer require. In addition to
these model-specific adjustments, there are a number of more general steps
you can take to improve the performance of any model:
•Use frame-based processing wherever possible. It is advantageous for the
entire model to be frame-based. See “Benefits of Frame-Based Processing” on
page 3-14 for more information.
•Use the
dspstartup file to tailor Simulink for DSP models, or manually
make the adjustments described in “Performance-Related Settings” on
page 2-13.
•Turn off the Simulink status bar by deselecting the
Status bar option in the
View menu. Simulation speed will improve, but the time indicator will not
be visible.
•Run your simulation from the MATLAB command line by typing
sim
(gcs)
This method of launching a simulation can greatly increase the simulation
speed, but also has several limitations:
- You cannot interact with the simulation (to tune parameters, for instance).
- You must press
Ctrl+C to stop the simulation, or specify start and stop
times.
- There are no graphics updates in M-file S-functions, which include blocks
such as the frame scopes (Vector Scope, etc.).
•Use the Real-Time Workshop to generate generic real-time (GRT) code
targeted to your host platform, and simulate the model using the generated
executable file. See the Real-Time Workshop documentation for more
information.
Algorithmic Delay
Algorithmic delay is delay that is intrinsic to the algorithm of a block or
subsystem, and is independent of CPU speed. In Chapter 5, “DSP Block
Reference,” and elsewhere in this guide, the algorithmic delay of a block is
referred to simply as the block’s delay. It is generally expressed in terms of the
number of samples by which a block’s output lags behind the corresponding