--- /dev/null
+<?xml version="1.0"?>
+<!--
+###################################################
+##Costas Loop
+###################################################
+ -->
+<block>
+ <name>Costas Loop</name>
+ <key>gr_costas_loop_cc</key>
+ <import>from gnuradio import gr</import>
+ <make>gr.costas_loop_cc($alpha, $beta, $max_freq, $min_freq, $order)</make>
+ <callback>set_alpha($alpha)</callback>
+ <callback>set_beta($beta)</callback>
+ <param>
+ <name>Alpha</name>
+ <key>alpha</key>
+ <type>real</type>
+ </param>
+ <param>
+ <name>Beta</name>
+ <key>beta</key>
+ <type>real</type>
+ </param>
+ <param>
+ <name>Max Freq</name>
+ <key>max_freq</key>
+ <type>real</type>
+ </param>
+ <param>
+ <name>Min Freq</name>
+ <key>min_freq</key>
+ <type>real</type>
+ </param>
+ <param>
+ <name>Order</name>
+ <key>order</key>
+ <type>int</type>
+ </param>
+ <sink>
+ <name>in</name>
+ <type>complex</type>
+ </sink>
+ <source>
+ <name>out</name>
+ <type>complex</type>
+ </source>
+ <source>
+ <name>out</name>
+ <type>complex</type>
+ <optional>1</optional>
+ </source>
+</block>