Implementation of TCH/F demapper block. See issue #38
diff --git a/grc/demapping/gsm_tch_f_chans_demapper.xml b/grc/demapping/gsm_tch_f_chans_demapper.xml
new file mode 100644
index 0000000..1aee0c6
--- /dev/null
+++ b/grc/demapping/gsm_tch_f_chans_demapper.xml
@@ -0,0 +1,28 @@
+<?xml version="1.0"?>
+<block>
+  <name>TCH/F chans demapper</name>
+  <key>gsm_tch_f_chans_demapper</key>
+  <import>import grgsm</import>
+  <make>grgsm.tch_f_chans_demapper($timemeslot_nr)</make>
+
+  <param>
+    <name>timemeslot_nr</name>
+    <key>timemeslot_nr</key>
+    <value>2</value>
+    <type>int</type>
+    <hide>part</hide>
+  </param>
+
+  <sink>
+    <name>bursts</name>
+    <type>message</type>
+  </sink>
+  <source>
+    <name>tch_bursts</name>
+    <type>message</type>
+  </source>
+  <source>
+    <name>acch_bursts</name>
+    <type>message</type>
+  </source>
+</block>