--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/m-toolbox/html_help/help/ug/gui_pzmodel_content.html	Wed Nov 23 19:22:13 2011 +0100
@@ -0,0 +1,29 @@
+<p>
+  The LTPDA toolbox contains a class (<tt>pzmodel</tt>) for creating and using pole/zero models. 
+  The <it>pole/zero model helper GUI</it> allows the user to visualise the pole/zero model as it's
+  being designed. It also allows the user to quickly see how the corresponding IIR filter 
+  (<tt>miir</tt> object) will look for different sample rates.
+</p>	
+<p>
+  To start the pole/zero model helper:
+  <div class="fragment">
+    <pre>
+      >> pzmodel_helper
+</pre>
+  </div>
+  or click the appropriate button on the LTPDA Launch Bay.
+</p>
+<p>
+  Once the GUI is loaded, you will see the following figure:
+</p>
+<br>
+<img src="images/pzmodel_helper.png" alt="pzmodel helper" border="3">
+<br>
+<p>
+  You can add poles and zeros to the model by entering the frequency (and Q) in the edit boxes, then click
+  <tt>Add pole</tt> or <tt>Add zero</tt> as appropriate. The response is then updated in the response axes.   
+</p>
+<br>
+<img src="images/pzmodel_helper_eg1.png" alt="pzmodel helper" border="3">
+<br>
+