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<refentry xml:id="fmconst" xml:lang="en"
          xmlns="http://docbook.org/ns/docbook"
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          xmlns:db="http://docbook.org/ns/docbook">

  <refnamediv>
    <refname>fmconst</refname>
	<refpurpose>Signal with constant frequency modulation</refpurpose>
  </refnamediv>
  <refsynopsisdiv>
    <title>Calling Sequence</title>
    <synopsis>
      [Y,IFLAW] = fmconst(N, FNORM, T0)
    </synopsis>
  </refsynopsisdiv>

  <refsection>
    <title>Parameters</title>
    <variablelist>
      <varlistentry>
        <term>N     :</term>
        <listitem><para>a positive integer: the number of points.</para></listitem>
      </varlistentry>
      <varlistentry>
        <term>FNORM :</term>
        <listitem>
          <para>a real scalar in [-0.5 0.5]: the normalized frequency (default: 0.25)</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term>T0    :</term>
        <listitem>
          <para>an  integer in [1 N]: the time center (default: round(N/2)).</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term>Y     :</term>
        <listitem>
          <para>a complex column vector of size N: the signal.</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term>IFLAW :</term>
        <listitem>
          <para>a real column vector of size N: the instantaneous frequency law (optional).</para>
        </listitem>
      </varlistentry>
    </variablelist>
  </refsection>

  <refsection>
    <title>Description</title>
    <para>
      fmconst generates a frequency modulation  with a constant frequency fnorm.
      The phase of this modulation is such that y(t0)=1.
    </para>
  </refsection>

  <refsection>
    <title>Examples</title>
    <programlisting role="example"><![CDATA[
    [X,IFLAW] = fmconst(128,0.05,50); 
    clf
    subplot(211); plot(real(X)); xtitle(_("Signal real part"))
    subplot(212); plot(IFLAW); xtitle(_("Instantaneous frequency law"))
    ]]></programlisting>
    <scilab:image><![CDATA[
    [X,IFLAW]=fmconst(128,0.05,50); 
    clf;
    subplot(211); plot(real(X));xtitle(_("Signal real part"))
    subplot(212); plot(IFLAW);xtitle(_("Instantaneous frequency law"))
    ]]></scilab:image>
  </refsection>

  <refsection role="see also">
    <title>See also</title>
    <simplelist type="inline">
      <member><link linkend="fmlin">fmlin</link></member>
      <member><link linkend="fmsin">fmsin</link></member>
      <member><link linkend="fmodany">fmodany</link></member>
      <member><link linkend="fmhyp">fmhyp</link></member>
      <member><link linkend="fmpar">fmpar</link></member>
      <member><link linkend="fmpower">fmpower</link></member>
    </simplelist>
  </refsection>

  <refsection>
    <title>Authors</title>
    <simplelist type="vert">
      <member>H. Nahrstaedt - Aug 2010</member>
      <member>F. Auger, July 1995.</member>
    </simplelist>
  </refsection>
</refentry>
