--- /dev/null
+<?xml version="1.0"?>
+<!--
+###################################################
+##Constellation Decoder
+###################################################
+ -->
+<block>
+ <name>Constellation Decoder</name>
+ <key>gr_constellation_decoder_cb</key>
+ <import>from gnuradio import gr</import>
+ <make>gr.constellation_decoder_cb($sym_position, $sym_value_out)</make>
+ <param>
+ <name>Symbol Position</name>
+ <key>sym_position</key>
+ <type>complex_vector</type>
+ </param>
+ <param>
+ <name>Symbol Value Out</name>
+ <key>sym_value_out</key>
+ <type>int_vector</type>
+ </param>
+ <sink>
+ <name>in</name>
+ <type>complex</type>
+ </sink>
+ <source>
+ <name>out</name>
+ <type>byte</type>
+ </source>
+</block>