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+<?xml version="1.0" encoding="UTF-8"?>
+
+<!--
+ *
+ * This help file was generated from bilinear.sci using help_from_sci().
+ *
+ -->
+
+<refentry version="5.0-subset Scilab" xml:id="bilinear" xml:lang="en"
+          xmlns="http://docbook.org/ns/docbook"
+          xmlns:xlink="http://www.w3.org/1999/xlink"
+          xmlns:svg="http://www.w3.org/2000/svg"
+          xmlns:ns3="http://www.w3.org/1999/xhtml"
+          xmlns:mml="http://www.w3.org/1998/Math/MathML"
+          xmlns:scilab="http://www.scilab.org"
+          xmlns:db="http://docbook.org/ns/docbook">
+
+  <refnamediv>
+    <refname>bilinear</refname>
+    <refpurpose>Transform a s-plane filter specification into a z-plane specification</refpurpose>
+  </refnamediv>
+
+
+<refsynopsisdiv>
+   <title>Calling Sequence</title>
+   <synopsis>
+   [ZB, ZA] = bilinear (SB, SA, T)
+   [ZB, ZA] = bilinear (SZ, SP, SG, T)
+   [ZZ, ZP, ZG] = bilinear (...)
+   </synopsis>
+</refsynopsisdiv>
+
+<refsection>
+   <title>Description</title>
+   <para>
+Transform a s-plane filter specification into a z-plane specification.  Filters can be specified in either zero-pole-gain or transfer function form.  The input form does not have to match the output form.  1/T is the sampling frequency represented in the z plane.
+   </para>
+   <para>
+Note: this differs from the bilinear function in the signal processing toolbox, which uses 1/T rather than T.
+   </para>
+   <para>
+Theory: Given a piecewise flat filter design, you can transform it from the s-plane to the z-plane while maintaining the band edges by means of the bilinear transform. This maps the left hand side of the s-plane into the interior of the unit circle. The mapping is highly non-linear, so you must design your filter with band edges in the s-plane positioned at 2/T tan(w*T/2) so that they will be positioned at w after the bilinear transform is complete.
+</para>
+</refsection>
+
+<refsection>
+   <title>Examples</title>
+   <programlisting role="example"><![CDATA[
+[ZB,ZA]=bilinear([1],[2,3],3)
+   ]]></programlisting>
+</refsection>
+</refentry>