added a note to oscil.xml about possible unexpected behaviour by Joac…

…him Heintz

opcodes/oscil.xml

@@ -8,7 +8,7 @@
   <refnamediv>
     <refname>oscil</refname>
     <refpurpose>
-      A simple oscillator.
+      A simple oscillator without any interpolation.
     </refpurpose>
   </refnamediv>
 
@@ -57,8 +57,17 @@
     <para>
       If you need to change the oscillator table with a k-rate signal, you can use <link linkend="oscilikt"><citetitle>oscilikt</citetitle></link>.
     </para>
-
- </refsect1>
+    <note>
+      <!-- <title>Title of the note (optional)</title> -->
+      <para>
+	    This opcode does not perform any interpolation.
+        This can lead to unexpected behaviour or unclean signals,
+        e.g. for small table sizes and low frequencies.
+        As standard oscillators the usage of <link linkend="oscili"><citetitle>oscili</citetitle></link>
+        or <link linkend="poscil"><citetitle>poscil</citetitle></link> is recommended.
+      </para>
+    </note>
+  </refsect1>
 
   <refsect1>
     <title>Examples</title>