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

  <refnamediv>
    <refname>altes</refname>
	<refpurpose>Altes signal in time domain</refpurpose>
  </refnamediv>

  <refsynopsisdiv>
    <title>Calling Sequence</title>
    <synopsis>
      x = altes(N)
      x = altes(N, fmin)
      x = altes(N, fmin, fmax)
      x = altes(N, fmin, fmax, alpha)
    </synopsis>
  </refsynopsisdiv>

  <refsection>
    <title>Parameters</title>
    <variablelist>
      <varlistentry>
        <term>N     :</term>
        <listitem>
          <para>A scalar with a positive integer value: the number of
          points in time</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term>fmin  :</term>
        <listitem>
          <para> a positive scalar: the  lower frequency bound (value of the hyperbolic
          instantaneous frequency law at the sample N), in normalized
          frequency (default is 0.05).</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term>fmax  :</term>
        <listitem>
          <para> a positive scalar: the upper frequency bound (value
          of the hyperbolic instantaneous frequency law at the first
          sample), in normalized frequency (default is 0.5).</para>
          <caution>fmax must be greater than fmin.</caution>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term>alpha :</term>
        <listitem>
          <para>a real scalar >1: the attenuation factor of the
          envelope (default is 300).</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term>x     :</term>
        <listitem>
          <para> real row vector containing the Altes signal samples. the associated time step is 1/</para>
        </listitem>
      </varlistentry>
    </variablelist>
  </refsection>

  <refsection>
    <title>Description</title>
    <para>
      altes generates the Altes signal in the time domain.
    </para>
    <para>
    </para>
  </refsection>

  <refsection>
    <title>Examples</title>
    <programlisting role="example"><![CDATA[
    N = 128;
    x = altes(N,0.1,0.45); 
    clf
    subplot(211); plot(1:N,x); xlabel(_("time"))
    y = fft(x);
    f = (0:(N/2))/N; Nf=size(f,"*");
    subplot(212); plot(f',abs(y(1:Nf))); xlabel(_("frequency"))
    // plots an Altes signal of 128 points whose normalized frequency goes from 0.45 down to 0.1.
    ]]></programlisting>
    <scilab:image><![CDATA[
     N=128;
    x=altes(N,0.1,0.45); 
    clf;
    subplot(211);plot((1:N)',x);xlabel(_("time"))
    y=fft(x);
    f=(0:(N/2))/N;Nf=size(f,"*");
    subplot(212);plot(f',abs(y(1:Nf)));xlabel(_("frequency"))
    ]]></scilab:image>
  </refsection>

  <refsection role="see also">
    <title>See also</title>
    <simplelist type="inline">
      <member><link linkend="klauder">klauder</link></member>
      <member><link linkend="anasing">anasing</link></member>
      <member><link linkend="anapulse">anapulse</link></member>
      <member><link linkend="anastep">anastep</link></member>
      <member><link linkend="doppler">doppler</link></member>
    </simplelist>
  </refsection>

  <refsection>
    <title>Authors</title>
    <simplelist type="vert">
      <member>H. Nahrstaedt - Aug 2010</member>
      <member>P. Goncalves - September 1995.</member>
    </simplelist>
  </refsection>
</refentry>
