<?xml version="1.0" encoding="ISO-8859-1" standalone="no"?>
<!DOCTYPE MAN SYSTEM "../../manrev.dtd">
<MAN>
  <LANGUAGE>eng</LANGUAGE>
  <TITLE>buttmag</TITLE>
  <TYPE>Scilab Function</TYPE>
  <DATE>April 1993</DATE>
  <SHORT_DESCRIPTION name="buttmag">  response of Butterworth filter</SHORT_DESCRIPTION>
  <CALLING_SEQUENCE>
    <CALLING_SEQUENCE_ITEM>[h]=buttmag(order,omegac,sample)  </CALLING_SEQUENCE_ITEM>
  </CALLING_SEQUENCE>
  <PARAM>
    <PARAM_INDENT>
      <PARAM_ITEM>
        <PARAM_NAME>order</PARAM_NAME>
        <PARAM_DESCRIPTION>
          <SP>: integer : filter order</SP>
        </PARAM_DESCRIPTION>
      </PARAM_ITEM>
      <PARAM_ITEM>
        <PARAM_NAME>omegac</PARAM_NAME>
        <PARAM_DESCRIPTION>
          <SP>: real : cut-off frequency in Hertz</SP>
        </PARAM_DESCRIPTION>
      </PARAM_ITEM>
      <PARAM_ITEM>
        <PARAM_NAME>sample</PARAM_NAME>
        <PARAM_DESCRIPTION>
          <SP>: vector of frequency where <VERB>buttmag</VERB> is evaluated</SP>
        </PARAM_DESCRIPTION>
      </PARAM_ITEM>
      <PARAM_ITEM>
        <PARAM_NAME>h</PARAM_NAME>
        <PARAM_DESCRIPTION>
          <SP>: Butterworth filter values at sample points</SP>
        </PARAM_DESCRIPTION>
      </PARAM_ITEM>
    </PARAM_INDENT>
  </PARAM>
  <DESCRIPTION>
    <P>
    squared magnitude response of a Butterworth filter
    <VERB>omegac</VERB> = cutoff frequency ; <VERB>sample</VERB> = sample of frequencies</P>
  </DESCRIPTION>
  <EXAMPLE>
<![CDATA[
//squared magnitude response of Butterworth filter
h=buttmag(13,300,1:1000);
mag=20*log(h)'/log(10);
plot2d((1:1000)',mag,[2],"011"," ",[0,-180,1000,20])
 ]]>
  </EXAMPLE>
  <AUTHOR>F. D.  </AUTHOR>
</MAN>
