<html><body><div style="color:#000; background-color:#fff; font-family:arial, helvetica, sans-serif;font-size:10pt"><div><span>Thank you, Serger !</span></div><div><span></span> </div><div><span>I just did not understand the Scilab functions:</span></div><span><pre style="font-family: Monospaced; font-style: normal;"><span style="color: rgb(0, 0, 0);">H</span> <span style="color: rgb(92, 92, 92);">=</span> <span style="color: rgb(174, 92, 176); text-decoration: underline;">syslin</span><span style="color: rgb(74, 85, 219);">(</span><span style="color: rgb(188, 143, 143);">'</span><span style="color: rgb(188, 143, 143);">c</span><span style="color: rgb(188, 143, 143);">'</span><span style="color: rgb(0, 0, 0);">,</span><span style="color: rgb(74, 85, 219);">(</span><span style="color: rgb(0, 0, 0);">s</span><span style="color: rgb(74, 85, 219);">)</span><span style="color: rgb(92, 92, 92);">/</span><span style="color: rgb(74, 85, 219);">(</span><span
style="color: rgb(0, 0, 0);">s</span><span style="color: rgb(92, 92, 92);">+</span><span style="color: rgb(188, 143, 143);">1</span><span style="color: rgb(74, 85, 219);">)</span><span style="color: rgb(74, 85, 219);">)</span><span style="color: rgb(0, 0, 0);">;</span> <span style="color: rgb(1, 168, 1); font-style: italic;">// set continuous time</span>
<span style="color: rgb(74, 85, 219);">[</span><span style="color: rgb(0, 0, 0);">f</span><span style="color: rgb(0, 0, 0);">,</span><span style="color: rgb(0, 0, 0);">y</span><span style="color: rgb(74, 85, 219);">]</span><span style="color: rgb(92, 92, 92);">=</span><span style="color: rgb(174, 92, 176); text-decoration: underline;">repfreq</span><span style="color: rgb(74, 85, 219);">(</span><span style="color: rgb(0, 0, 0);">H</span><span style="color: rgb(0, 0, 0);">,</span><span style="color: rgb(188, 143, 143);">0.001</span><span style="color: rgb(0, 0, 0);">,</span><span style="color: rgb(188, 143, 143);">100</span><span style="color: rgb(74, 85, 219);">)</span><span style="color: rgb(0, 0, 0);">;</span></pre></span><div> </div><div>All best.</div><div>Reinaldo.<br></div><div style="font-family: arial, helvetica, sans-serif; font-size: 10pt;"><div style="font-family: times new roman, new york, times, serif; font-size: 12pt;"><font size="2"
face="Arial"><div style="margin: 5px 0px; padding: 0px; border: 1px solid rgb(204, 204, 204); height: 0px; line-height: 0; font-size: 0px;" class="hr" contentEditable="false" readonly="true"></div><b><span style="font-weight: bold;">From:</span></b> Serge Steer <Serge.Steer@inria.fr><br><b><span style="font-weight: bold;">To:</span></b> users@lists.scilab.org<br><b><span style="font-weight: bold;">Sent:</span></b> Monday, September 19, 2011 12:49 PM<br><b><span style="font-weight: bold;">Subject:</span></b> Re: [scilab-Users] Bode Diagram and how can I plot those functions on different graph windows ?<br></font><br><div id="yiv974548526">
Le 19/09/2011 17:06, Reinaldo a écrit :
<blockquote type="cite">
<pre style="font-family: Monospaced; font-style: normal;"><span style="color: rgb(1, 168, 1); font-style: italic;">/ Define "s" as variable </span>
<span style="color: rgb(1, 168, 1); font-style: italic;">// (s é um polinômio de raiz zero)</span>
<span style="color: rgb(0, 0, 0);">s</span> <span style="color: rgb(92, 92, 92);">=</span> <span style="color: rgb(50, 185, 185);">poly</span><span style="color: rgb(74, 85, 219);">(</span><span style="color: rgb(188, 143, 143);">0</span><span style="color: rgb(0, 0, 0);">,</span><span style="color: rgb(188, 143, 143);">'</span><span style="color: rgb(188, 143, 143);">s</span><span style="color: rgb(188, 143, 143);">'</span><span style="color: rgb(74, 85, 219);">)</span><span style="color: rgb(0, 0, 0);">;</span>
<span style="color: rgb(1, 168, 1); font-style: italic;">// Define the transfer function:</span></pre>
<pre style="font-family: Monospaced; font-style: normal;"><span style="color: rgb(1, 168, 1); font-style: italic;"></span><span style="color: rgb(0, 0, 0);">H</span> <span style="color: rgb(92, 92, 92);">=</span> <span style="color: rgb(74, 85, 219);">(</span><span style="color: rgb(0, 0, 0);">s</span><span style="color: rgb(74, 85, 219);">)</span><span style="color: rgb(92, 92, 92);">/</span><span style="color: rgb(74, 85, 219);">(</span><span style="color: rgb(0, 0, 0);">s</span><span style="color: rgb(92, 92, 92);">+</span><span style="color: rgb(188, 143, 143);">1</span><span style="color: rgb(74, 85, 219);">)</span><span style="color: rgb(0, 0, 0);">;</span>
<span style="color: rgb(1, 168, 1); font-style: italic;">// Define the frequency range (Hz)</span>
<span style="color: rgb(0, 0, 0);">f</span> <span style="color: rgb(92, 92, 92);">=</span> <span style="color: rgb(188, 143, 143);">0.001</span><span style="color: rgb(255, 170, 0);">:</span><span style="color: rgb(188, 143, 143);">0.001</span><span style="color: rgb(255, 170, 0);">:</span><span style="color: rgb(188, 143, 143);">100</span><span style="color: rgb(0, 0, 0);">;</span>
<span style="color: rgb(1, 168, 1); font-style: italic;">// Calculate the frequency-response:</span></pre>
<pre style="font-family: Monospaced; font-style: normal;"><span style="color: rgb(1, 168, 1); font-style: italic;"></span><span style="color: rgb(0, 0, 0);">y</span> <span style="color: rgb(92, 92, 92);">=</span> <span style="color: rgb(50, 185, 185);">freq</span><span style="color: rgb(74, 85, 219);">(</span><span style="color: rgb(0, 0, 0);">H</span><span style="color: rgb(92, 92, 92);">.</span><span style="color: rgb(170, 170, 170);">num</span><span style="color: rgb(0, 0, 0);">,</span><span style="color: rgb(0, 0, 0);">H</span><span style="color: rgb(92, 92, 92);">.</span><span style="color: rgb(170, 170, 170);">den</span><span style="color: rgb(0, 0, 0);">,</span><span style="color: rgb(188, 143, 143);">2</span><span style="color: rgb(92, 92, 92);">*</span><span style="color: rgb(218, 112, 214);">%pi</span><span style="color: rgb(92, 92, 92);">*</span><span style="color: rgb(218, 112, 214);">%i</span><span style="color: rgb(92, 92,
92);">*</span><span style="color: rgb(0, 0, 0);">f</span><span style="color: rgb(74, 85, 219);">)</span><span style="color: rgb(0, 0, 0);">;</span>
<span style="color: rgb(1, 168, 1); font-style: italic;">// Calculate the absolute value function module:</span></pre>
<pre style="font-family: Monospaced; font-style: normal;"><span style="color: rgb(1, 168, 1); font-style: italic;"></span><span style="color: rgb(0, 0, 0);">yabs</span> <span style="color: rgb(92, 92, 92);">=</span> <span style="color: rgb(50, 185, 185);">abs</span><span style="color: rgb(74, 85, 219);">(</span><span style="color: rgb(0, 0, 0);">y</span><span style="color: rgb(74, 85, 219);">)</span><span style="color: rgb(0, 0, 0);">;</span>
<span style="color: rgb(1, 168, 1); font-style: italic;">// Calcula the function module in dB</span>
<span style="color: rgb(0, 0, 0);">ym</span> <span style="color: rgb(92, 92, 92);">=</span> <span style="color: rgb(188, 143, 143);">20</span><span style="color: rgb(92, 92, 92);">*</span><span style="color: rgb(174, 92, 176); text-decoration: underline;">log10</span><span style="color: rgb(74, 85, 219);">(</span><span style="color: rgb(50, 185, 185);">abs</span><span style="color: rgb(74, 85, 219);">(</span><span style="color: rgb(0, 0, 0);">y</span><span style="color: rgb(74, 85, 219);">)</span><span style="color: rgb(74, 85, 219);">)</span><span style="color: rgb(0, 0, 0);">;</span>
</pre>
<pre style="font-family: Monospaced; font-style: normal;"><span style="color: rgb(1, 168, 1); font-style: italic;">// Calculate the phase function in degree:</span>
<span style="color: rgb(0, 0, 0);">yf</span> <span style="color: rgb(92, 92, 92);">=</span> <span style="color: rgb(74, 85, 219);">(</span><span style="color: rgb(188, 143, 143);">180</span><span style="color: rgb(92, 92, 92);">/</span><span style="color: rgb(218, 112, 214);">%pi</span><span style="color: rgb(74, 85, 219);">)</span><span style="color: rgb(92, 92, 92);">*</span><span style="color: rgb(50, 185, 185);">atan</span><span style="color: rgb(74, 85, 219);">(</span><span style="color: rgb(50, 185, 185);">imag</span><span style="color: rgb(74, 85, 219);">(</span><span style="color: rgb(0, 0, 0);">y</span><span style="color: rgb(74, 85, 219);">)</span><span style="color: rgb(0, 0, 0);">,</span> <span style="color: rgb(50, 185, 185);">real</span><span style="color: rgb(74, 85, 219);">(</span><span style="color: rgb(0, 0, 0);">y</span><span style="color: rgb(74, 85, 219);">)</span><span style="color: rgb(74, 85, 219);">)</span><span style="color:
rgb(0, 0, 0);">;</span>
<span style="color: rgb(1, 168, 1); font-style: italic;">// open and clean the graph window</span>
<span style="color: rgb(0, 0, 0);">xbasc</span><span style="color: rgb(74, 85, 219);">(</span><span style="color: rgb(74, 85, 219);">)</span><span style="color: rgb(0, 0, 0);">,</span>
<span style="color: rgb(1, 168, 1); font-style: italic;">// Divide the graph window in three rows:</span>
<span style="color: rgb(174, 92, 176); text-decoration: underline;">subplot</span><span style="color: rgb(74, 85, 219);">(</span><span style="color: rgb(188, 143, 143);">3</span><span style="color: rgb(0, 0, 0);">,</span><span style="color: rgb(188, 143, 143);">1</span><span style="color: rgb(0, 0, 0);">,</span><span style="color: rgb(188, 143, 143);">1</span><span style="color: rgb(74, 85, 219);">)</span><span style="color: rgb(0, 0, 0);">,</span>
<span style="color: rgb(50, 185, 185);">plot2d</span><span style="color: rgb(74, 85, 219);">(</span><span style="color: rgb(188, 143, 143);">'</span><span style="color: rgb(188, 143, 143);">ln</span><span style="color: rgb(188, 143, 143);">'</span><span style="color: rgb(0, 0, 0);">,</span><span style="color: rgb(0, 0, 0);">f</span><span style="color: rgb(0, 0, 0);">,</span><span style="color: rgb(0, 0, 0);">yabs</span><span style="color: rgb(0, 0, 0);">,</span><span style="color: rgb(0, 0, 0);">style</span><span style="color: rgb(92, 92, 92);">=</span><span style="color: rgb(188, 143, 143);">2</span><span style="color: rgb(74, 85, 219);">)</span><span style="color: rgb(0, 0, 0);">,</span>
<span style="color: rgb(50, 185, 185);">xgrid</span><span style="color: rgb(74, 85, 219);">(</span><span style="color: rgb(74, 85, 219);">)</span><span style="color: rgb(0, 0, 0);">,</span>
<span style="color: rgb(50, 185, 185);">xtitle</span><span style="color: rgb(74, 85, 219);">(</span><span style="color: rgb(188, 143, 143);">"</span><span style="color: rgb(188, 143, 143);">Modulo em valores absolutos da Função de Transferência</span><span style="color: rgb(188, 143, 143);">"</span><span style="color: rgb(0, 0, 0);">,</span><span style="color: rgb(188, 143, 143);">"</span><span style="color: rgb(188, 143, 143);">Freqüência [Hz]</span><span style="color: rgb(188, 143, 143);">"</span><span style="color: rgb(0, 0, 0);">,</span><span style="color: rgb(188, 143, 143);">"</span><span style="color: rgb(188, 143, 143);">Módulo em dB</span><span style="color: rgb(188, 143, 143);">"</span><span style="color: rgb(74, 85, 219);">)</span><span style="color: rgb(0, 0, 0);">;</span></pre>
<pre style="font-family: Monospaced; font-style: normal;"><span style="color: rgb(174, 92, 176); text-decoration: underline;">subplot</span><span style="color: rgb(74, 85, 219);">(</span><span style="color: rgb(188, 143, 143);">3</span><span style="color: rgb(0, 0, 0);">,</span><span style="color: rgb(188, 143, 143);">1</span><span style="color: rgb(0, 0, 0);">,</span><span style="color: rgb(188, 143, 143);">2</span><span style="color: rgb(74, 85, 219);">)</span><span style="color: rgb(0, 0, 0);">,</span>
<span style="color: rgb(50, 185, 185);">plot2d</span><span style="color: rgb(74, 85, 219);">(</span><span style="color: rgb(188, 143, 143);">'</span><span style="color: rgb(188, 143, 143);">ln</span><span style="color: rgb(188, 143, 143);">'</span><span style="color: rgb(0, 0, 0);">,</span><span style="color: rgb(0, 0, 0);">f</span><span style="color: rgb(0, 0, 0);">,</span><span style="color: rgb(0, 0, 0);">ym</span><span style="color: rgb(0, 0, 0);">,</span><span style="color: rgb(0, 0, 0);">style</span><span style="color: rgb(92, 92, 92);">=</span><span style="color: rgb(188, 143, 143);">2</span><span style="color: rgb(74, 85, 219);">)</span><span style="color: rgb(0, 0, 0);">,</span>
<span style="color: rgb(50, 185, 185);">xgrid</span><span style="color: rgb(74, 85, 219);">(</span><span style="color: rgb(74, 85, 219);">)</span><span style="color: rgb(0, 0, 0);">,</span>
<span style="color: rgb(50, 185, 185);">xtitle</span><span style="color: rgb(74, 85, 219);">(</span><span style="color: rgb(188, 143, 143);">"</span><span style="color: rgb(188, 143, 143);">Modulo em dB da Função de Transferência</span><span style="color: rgb(188, 143, 143);">"</span><span style="color: rgb(0, 0, 0);">,</span><span style="color: rgb(188, 143, 143);">"</span><span style="color: rgb(188, 143, 143);">Freqüência [Hz]</span><span style="color: rgb(188, 143, 143);">"</span><span style="color: rgb(0, 0, 0);">,</span><span style="color: rgb(188, 143, 143);">"</span><span style="color: rgb(188, 143, 143);">Módulo em dB</span><span style="color: rgb(188, 143, 143);">"</span><span style="color: rgb(74, 85, 219);">)</span><span style="color: rgb(0, 0, 0);">;</span>
</pre>
<pre style="font-family: Monospaced; font-style: normal;"><span style="color: rgb(174, 92, 176); text-decoration: underline;">subplot</span><span style="color: rgb(74, 85, 219);">(</span><span style="color: rgb(188, 143, 143);">3</span><span style="color: rgb(0, 0, 0);">,</span><span style="color: rgb(188, 143, 143);">1</span><span style="color: rgb(0, 0, 0);">,</span><span style="color: rgb(188, 143, 143);">3</span><span style="color: rgb(74, 85, 219);">)</span><span style="color: rgb(0, 0, 0);">,</span>
<span style="color: rgb(50, 185, 185);">plot2d</span><span style="color: rgb(74, 85, 219);">(</span><span style="color: rgb(188, 143, 143);">'</span><span style="color: rgb(188, 143, 143);">ln</span><span style="color: rgb(188, 143, 143);">'</span><span style="color: rgb(0, 0, 0);">,</span><span style="color: rgb(0, 0, 0);">f</span><span style="color: rgb(0, 0, 0);">,</span><span style="color: rgb(0, 0, 0);">yf</span><span style="color: rgb(0, 0, 0);">,</span><span style="color: rgb(0, 0, 0);">style</span><span style="color: rgb(92, 92, 92);">=</span><span style="color: rgb(188, 143, 143);">3</span><span style="color: rgb(74, 85, 219);">)</span><span style="color: rgb(0, 0, 0);">,</span>
<span style="color: rgb(50, 185, 185);">xtitle</span><span style="color: rgb(74, 85, 219);">(</span><span style="color: rgb(188, 143, 143);">"</span><span style="color: rgb(188, 143, 143);">Fase da Função de Transferência</span><span style="color: rgb(188, 143, 143);">"</span><span style="color: rgb(0, 0, 0);">,</span><span style="color: rgb(188, 143, 143);">"</span><span style="color: rgb(188, 143, 143);">Freqüência [Hz]</span><span style="color: rgb(188, 143, 143);">"</span><span style="color: rgb(0, 0, 0);">,</span><span style="color: rgb(188, 143, 143);">"</span><span style="color: rgb(188, 143, 143);">Fase em Graus</span><span style="color: rgb(188, 143, 143);">"</span><span style="color: rgb(74, 85, 219);">)</span><span style="color: rgb(0, 0, 0);">;</span>
<span style="color: rgb(50, 185, 185);">xgrid</span><span style="color: rgb(74, 85, 219);">(</span><span style="color: rgb(74, 85, 219);">)</span><span style="color: rgb(0, 0, 0);">;</span></pre>
</blockquote>
<br>
You can modify the margins properties for that <br>
Note that you can use repfreq to compute the frequency dicretisation
and the frequency response<br>
the following code pllies both solutions <br>
<br>
<br>
<br>
// Define "s" as variable <br>
// (s é um polinômio de raiz zero)<br>
s = poly(0,'s');<br>
// Define the transfer function:<br>
H = syslin('c',(s)/(s+1)); // set continuous time<br>
[f,y]=repfreq(H,0.001,100);<br>
<br>
// Calculate the absolute value function module:<br>
<br>
yabs = abs(y); <br>
// Calcula the function module in dB<br>
ym = 20*log10(abs(y));<br>
<br>
// Calculate the phase function in degree:<br>
yf = (180/%pi)*atan(imag(y), real(y));<br>
<br>
// open and clean the graph window<br>
clf(),<br>
// Divide the graph window in three rows:<br>
subplot(3,1,1),<br>
plot2d('ln',f,yabs,style=2),<br>
ax=gca();<br>
ax.margins(3:4)=0.24;<br>
xgrid(),<br>
xtitle("Modulo em valores absolutos da Função de
Transferência","Freqüência [Hz]","Módulo em dB");<br>
<br>
subplot(3,1,2),<br>
plot2d('ln',f,ym,style=2),<br>
ax=gca();<br>
ax.margins(3:4)=0.24;<br>
xgrid(),<br>
xtitle("Modulo em dB da Função de Transferência","Freqüência
[Hz]","Módulo em dB");<br>
<br>
subplot(3,1,3),<br>
plot2d('ln',f,yf,style=3),<br>
xtitle("Fase da Função de Transferência","Freqüência [Hz]","Fase em
Graus");<br>
ax=gca();<br>
ax.margins(3:4)=0.24;<br>
xgrid();<br>
<br>
<br>
<br>
Serge Steer<br>
INRIA<br>
</div><br><br></div></div></div></body></html>