grc/receiver/gsm_clock_offset_control.xml

<?xml version="1.0"?>
<block>
  <name>GSM clock offset control</name>
  <key>gsm_clock_offset_control</key>
  <import>import gsm</import>
  <make>gsm.clock_offset_control($fc)</make>
  <callback></callback>
  <param>
    <name>fc</name>
    <key>fc</key>
    <value>fc</value>
    <type>float</type>
  </param>

  <sink>
    <name>measurements</name>
    <type>message</type>
  </sink>

  <source>
    <name>ppm</name>
    <type>message</type>
    <optional>1</optional>
  </source>
</block>