1 files changed, 80 insertions, 1 deletions
diff --git a/help/en_US/sos2ss.xml b/help/en_US/sos2ss.xml
index 99a5812..d69c4c7 100644
--- a/help/en_US/sos2ss.xml
+++ b/help/en_US/sos2ss.xml
@@ -17,7 +17,86 @@
 
   <refnamediv>
     <refname>sos2ss</refname>
-    <refpurpose>[nargout,nargin]=argn();</refpurpose>
+    <refpurpose>Converts Digital Filter Second order section parameters to steady state form. </refpurpose>
   </refnamediv>
 
+
+<refsection>
+<title>Calling Sequence</title>
+
+[A,B,C,D] = sos2ss(sos)
+[A,B,C,D] = sos2ss(sos,g)
+
+</refsection>
+<refsection>
+   <title>Parameters</title>
+   <variablelist>
+   <varlistentry><term>[A,B,C,D]:</term>
+      <listitem><para>Steady state parameters.</para></listitem></varlistentry>
+   <varlistentry><term>sos:</term>
+      <listitem><para> Second order sectional matrix.</para></listitem></varlistentry>
+   <varlistentry><term>g:</term>
+      <listitem><para>gain of the system.</para></listitem></varlistentry>
+   </variablelist>
+</refsection>
+
+
+<refsection>
+<title>Description</title>
+<para>sos2ss converts a second-order section representation of a digital filter to an equivalent state-space representation.</para>
+<para>
+[A,B,C,D] = sos2ss(sos) converts sos, a system expressed in second-order section form, to a single-input, single-output state-space representation:
+
+x(n+1)=Ax(n)+Bu(n),
+y(n)=Cx(n)+Du(n).</para>
+
+<para>
+
+ <latex>
+      \begin{eqnarray}
+      f(x,a,r) = \frac{1}{r^{-a}\Gamma(a)} \int_0^x t^{a-1} \exp\left(-rt\right) dt
+      \end{eqnarray}
+    </latex>
+
+</para>
+
+
+
+</refsection>
+
+<refsection>
+   <title>Examples</title>
+   <programlisting role="example"><![CDATA[
+sos = [1  1  1  1   0  -1 ;
+         -2  3  1  1  10   1];
+[A,B,C,D] = sos2ss(sos,2);
+//EXPECTED OUTPUT:
+//D  =- 4.
+//C  =42.    4.  - 32.  - 2.
+//B  =[1.  0.  0.    0.    0.]'
+//A  =[- 10.    0.    10.    1. ; 1.     0.    0.     0.  ; 0.     1.    0.     0.  ;  0.     0.    1.     0.  ]
+   ]]></programlisting>
+</refsection>
+
+
+<refsection>
+   <title>Authors</title>
+   <simplelist type="vert">
+   <member>Parthasrathi Panda</member>
+   </simplelist>
+</refsection>
+
+
+
+<refsection>
+   <title>See also</title>
+   <simplelist type="inline">
+   <member><link linkend="sos2tf">abs</link></member>
+   <member><link linkend="sosbreak">mean</link></member>
+   <member><link linkend="sos2ss">max</link></member>
+
+   </simplelist>
+</refsection>
+
+
 </refentry>