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<!DOCTYPE MAN SYSTEM "../../manrev.dtd">
<MAN>
  <LANGUAGE>eng</LANGUAGE>
  <TITLE>calfrq</TITLE>
  <TYPE>Scilab Function</TYPE>
  <DATE>April 1993</DATE>
  <SHORT_DESCRIPTION name="calfrq"> frequency response discretization</SHORT_DESCRIPTION>
  <CALLING_SEQUENCE>
    <CALLING_SEQUENCE_ITEM>[frq,split]=calfrq(h,[fmin,fmax])  </CALLING_SEQUENCE_ITEM>
  </CALLING_SEQUENCE>
  <PARAM>
    <PARAM_INDENT>
      <PARAM_ITEM>
        <PARAM_NAME>h</PARAM_NAME>
        <PARAM_DESCRIPTION>
          <SP>: SISO linear system (<VERB>syslin</VERB> list)</SP>
        </PARAM_DESCRIPTION>
      </PARAM_ITEM>
      <PARAM_ITEM>
        <PARAM_NAME>fmin,fmax</PARAM_NAME>
        <PARAM_DESCRIPTION>
          <SP>: real scalars (min and max frequencies)</SP>
        </PARAM_DESCRIPTION>
      </PARAM_ITEM>
      <PARAM_ITEM>
        <PARAM_NAME>frq</PARAM_NAME>
        <PARAM_DESCRIPTION>
          <SP>: row vector (discretization of interval)</SP>
        </PARAM_DESCRIPTION>
      </PARAM_ITEM>
      <PARAM_ITEM>
        <PARAM_NAME>split</PARAM_NAME>
        <PARAM_DESCRIPTION>
          <SP>: vector of frq splitting points indexes</SP>
        </PARAM_DESCRIPTION>
      </PARAM_ITEM>
    </PARAM_INDENT>
  </PARAM>
  <DESCRIPTION>
    <P>
    frequency response discretization ; <VERB>frq</VERB> is the discretization of  
    <VERB>[fmin,fmax]</VERB> 
    such that the peaks in the frequency response are well represented.</P>
    <P>
    Default values for <VERB>fmin</VERB> and <VERB>fmax</VERB> are
    <VERB>1.d-3</VERB>, <VERB>1.d+3</VERB> if <VERB>h</VERB> is continuous-time
    or <VERB>1.d-3</VERB>, <VERB>1/(2*h('dt'))</VERB> if <VERB>h</VERB> is discrete-time.</P>
    <P>
    Singularities are located between <VERB>frq(split(k))</VERB> and <VERB>frq(split(k)+1)</VERB>
    for <VERB>k&gt;1</VERB>.</P>
  </DESCRIPTION>
  <EXAMPLE>
<![CDATA[
s=poly(0,'s')
h=syslin('c',(s^2+2*0.9*10*s+100)/(s^2+2*0.3*10.1*s+102.01))
h1=h*syslin('c',(s^2+2*0.1*15.1*s+228.01)/(s^2+2*0.9*15*s+225)) 
[f1,spl]=calfrq(h1,0.01,1000);
rf=repfreq(h1,f1);
plot2d(real(rf)',imag(rf)')
 ]]>
  </EXAMPLE>
  <SEE_ALSO>
    <SEE_ALSO_ITEM>
      <LINK>bode</LINK>
    </SEE_ALSO_ITEM>
    <SEE_ALSO_ITEM>
      <LINK>black</LINK>
    </SEE_ALSO_ITEM>
    <SEE_ALSO_ITEM>
      <LINK>nyquist</LINK>
    </SEE_ALSO_ITEM>
    <SEE_ALSO_ITEM>
      <LINK>freq</LINK>
    </SEE_ALSO_ITEM>
    <SEE_ALSO_ITEM>
      <LINK>repfreq</LINK>
    </SEE_ALSO_ITEM>
    <SEE_ALSO_ITEM>
      <LINK>logspace</LINK>
    </SEE_ALSO_ITEM>
  </SEE_ALSO>
</MAN>
