Getting started with simulink
In this section, we will learn the basics of Simulink and build a simple system.
For help on "Simulink" click here . For the following sections download the file Lab3Utilities.zip .
To get the library of Simulink functions for this laboratory, download the file Lab3Utilities.zip . Once Matlab is started, type “Lab3” to bring up the libraryof Simulink components shown in [link] . This library contains a full library of Simulink blocks,a spectrum analyzer and network analyzer designed for this laboratory, a sine wave generator, a scope,and pre-design systems for each of the experiments that you will be running.
In order to familiarize yourself with Simulink, you will first build the system shown in [link] . This system consists of a sine wave generatorthat feeds a scope and a spectrum analyzer.
- Open a window for a new system by using the
New
option from theFile
pull-down menu, and selectModel
. - Drag the
Sine Wave
,Scope
, andSpectrum Analyzer
blocks from theLab3
window into the new window you created. - Now you need to connect these three blocks.
With the left mouse button, click on the output of the
Sine Wave
and drag it to the input of theScope
. Now use the right button to click on the line you just created, and dragto the input of theSpectrum Analyzer
block. Your system should now look like [link] . - Double click on the
Scope
block to make the plotting window for the scope appear. - Set the simulation parameters by selecting
Configuration Parameters
from theSimulation
pull-down menu. Under theSolver
tab, set theStop time
to 50, and theMax step size
to 0.02. Then selectOK
. This will allow the Spectrum Analyzer to make a more accurate calculation. - Start the simulation by using the
Start
option from theSimulation
pull-down menu. A standard Matlab figure window will pop up showingthe output of theSpectrum Analyzer
. - Change the frequency of the sine wave to
5*pi rad/sec
by double clicking on theSine Wave
icon and changing the number in theFrequency
field. Restart the simulation. Observe the change in the waveform andits spectral density. If you want to change the time scaling in the plot generated by the spectrum analyzer, from the Matlab prompt use thesubplot(2,1,1)
andaxis()
commands. - When you are done, close the system window you created
by using the
Close
option from theFile
pull-down menu.
Continuous-time frequency analysis
For help on the following topics select the corresponding link: simulink or printing figures in Simulink .
In this section, we will study the use and properties of the continuous-time Fourier transform with Simulink.The Simulink package is especially useful for continuous-time systems because it allows thesimulation of their behavior on a digital computer.
Synthesis of periodic signals
Double click the icon labeled
Synthesizer
to bring up a model as shown in
[link] .
This system may be used to synthesize periodic signals byadding together the harmonic components of a Fourier series
expansion.Each
Sin Wave
block can be set to a specific frequency,amplitude and phase.
The initial settings of the
Sin Wave
blocks are set
to generate the Fourier series expansion