diff --git a/examples/receiver_rtlsdr.grc b/examples/receiver_rtlsdr.grc
index d3d45c5..3c1cb5f 100644
--- a/examples/receiver_rtlsdr.grc
+++ b/examples/receiver_rtlsdr.grc
@@ -1,6 +1,6 @@
 <?xml version='1.0' encoding='ASCII'?>
 <flow_graph>
-  <timestamp>Wed Aug  6 15:19:45 2014</timestamp>
+  <timestamp>Wed Aug  6 15:56:33 2014</timestamp>
   <block>
     <key>options</key>
     <param>
@@ -92,53 +92,6 @@
     </param>
   </block>
   <block>
-    <key>clk_offset_corrector</key>
-    <param>
-      <key>id</key>
-      <value>clk_offset_corrector_0</value>
-    </param>
-    <param>
-      <key>_enabled</key>
-      <value>True</value>
-    </param>
-    <param>
-      <key>ppm</key>
-      <value>0</value>
-    </param>
-    <param>
-      <key>samp_rate</key>
-      <value>samp_rate</value>
-    </param>
-    <param>
-      <key>fc</key>
-      <value>936.6e6</value>
-    </param>
-    <param>
-      <key>alias</key>
-      <value></value>
-    </param>
-    <param>
-      <key>affinity</key>
-      <value></value>
-    </param>
-    <param>
-      <key>minoutbuf</key>
-      <value>0</value>
-    </param>
-    <param>
-      <key>maxoutbuf</key>
-      <value>0</value>
-    </param>
-    <param>
-      <key>_coordinate</key>
-      <value>(381, 306)</value>
-    </param>
-    <param>
-      <key>_rotation</key>
-      <value>0</value>
-    </param>
-  </block>
-  <block>
     <key>gsm_get_bcch_or_ccch_bursts</key>
     <param>
       <key>id</key>
@@ -264,27 +217,133 @@
     </param>
   </block>
   <block>
-    <key>gsm_receiver_hier</key>
+    <key>variable_slider</key>
     <param>
       <key>id</key>
-      <value>gsm_receiver_hier_0</value>
+      <value>fc</value>
     </param>
     <param>
       <key>_enabled</key>
       <value>True</value>
     </param>
     <param>
-      <key>input_rate</key>
-      <value>samp_rate</value>
+      <key>label</key>
+      <value></value>
     </param>
     <param>
-      <key>osr</key>
-      <value>4</value>
+      <key>value</key>
+      <value>940e6</value>
     </param>
     <param>
-      <key>arfcn</key>
+      <key>min</key>
+      <value>800e6</value>
+    </param>
+    <param>
+      <key>max</key>
+      <value>1000e6</value>
+    </param>
+    <param>
+      <key>num_steps</key>
+      <value>1000</value>
+    </param>
+    <param>
+      <key>style</key>
+      <value>wx.SL_HORIZONTAL</value>
+    </param>
+    <param>
+      <key>converver</key>
+      <value>float_converter</value>
+    </param>
+    <param>
+      <key>grid_pos</key>
+      <value></value>
+    </param>
+    <param>
+      <key>notebook</key>
+      <value></value>
+    </param>
+    <param>
+      <key>alias</key>
+      <value></value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(333, 29)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
       <value>0</value>
     </param>
+  </block>
+  <block>
+    <key>variable_slider</key>
+    <param>
+      <key>id</key>
+      <value>g</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>label</key>
+      <value></value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>43</value>
+    </param>
+    <param>
+      <key>min</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>max</key>
+      <value>100</value>
+    </param>
+    <param>
+      <key>num_steps</key>
+      <value>100</value>
+    </param>
+    <param>
+      <key>style</key>
+      <value>wx.SL_HORIZONTAL</value>
+    </param>
+    <param>
+      <key>converver</key>
+      <value>float_converter</value>
+    </param>
+    <param>
+      <key>grid_pos</key>
+      <value></value>
+    </param>
+    <param>
+      <key>notebook</key>
+      <value></value>
+    </param>
+    <param>
+      <key>alias</key>
+      <value></value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(217, 29)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gsm_control_channels_decoder</key>
+    <param>
+      <key>id</key>
+      <value>gsm_control_channels_decoder_0</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
     <param>
       <key>alias</key>
       <value></value>
@@ -303,7 +362,7 @@
     </param>
     <param>
       <key>_coordinate</key>
-      <value>(585, 306)</value>
+      <value>(821, 371)</value>
     </param>
     <param>
       <key>_rotation</key>
@@ -354,105 +413,6 @@
     </param>
   </block>
   <block>
-    <key>wxgui_fftsink2</key>
-    <param>
-      <key>id</key>
-      <value>wxgui_fftsink2_0</value>
-    </param>
-    <param>
-      <key>_enabled</key>
-      <value>True</value>
-    </param>
-    <param>
-      <key>type</key>
-      <value>complex</value>
-    </param>
-    <param>
-      <key>title</key>
-      <value>FFT Plot</value>
-    </param>
-    <param>
-      <key>samp_rate</key>
-      <value>samp_rate</value>
-    </param>
-    <param>
-      <key>baseband_freq</key>
-      <value>0</value>
-    </param>
-    <param>
-      <key>y_per_div</key>
-      <value>10</value>
-    </param>
-    <param>
-      <key>y_divs</key>
-      <value>10</value>
-    </param>
-    <param>
-      <key>ref_level</key>
-      <value>0</value>
-    </param>
-    <param>
-      <key>ref_scale</key>
-      <value>2.0</value>
-    </param>
-    <param>
-      <key>fft_size</key>
-      <value>1024</value>
-    </param>
-    <param>
-      <key>fft_rate</key>
-      <value>15</value>
-    </param>
-    <param>
-      <key>peak_hold</key>
-      <value>False</value>
-    </param>
-    <param>
-      <key>average</key>
-      <value>False</value>
-    </param>
-    <param>
-      <key>avg_alpha</key>
-      <value>0</value>
-    </param>
-    <param>
-      <key>win</key>
-      <value>None</value>
-    </param>
-    <param>
-      <key>win_size</key>
-      <value></value>
-    </param>
-    <param>
-      <key>grid_pos</key>
-      <value></value>
-    </param>
-    <param>
-      <key>notebook</key>
-      <value></value>
-    </param>
-    <param>
-      <key>freqvar</key>
-      <value>None</value>
-    </param>
-    <param>
-      <key>alias</key>
-      <value></value>
-    </param>
-    <param>
-      <key>affinity</key>
-      <value></value>
-    </param>
-    <param>
-      <key>_coordinate</key>
-      <value>(585, 386)</value>
-    </param>
-    <param>
-      <key>_rotation</key>
-      <value>0</value>
-    </param>
-  </block>
-  <block>
     <key>rtlsdr_source</key>
     <param>
       <key>id</key>
@@ -704,44 +664,76 @@
     </param>
   </block>
   <block>
-    <key>variable_slider</key>
+    <key>wxgui_fftsink2</key>
     <param>
       <key>id</key>
-      <value>fc</value>
+      <value>wxgui_fftsink2_0</value>
     </param>
     <param>
       <key>_enabled</key>
       <value>True</value>
     </param>
     <param>
-      <key>label</key>
+      <key>type</key>
+      <value>complex</value>
+    </param>
+    <param>
+      <key>title</key>
+      <value>FFT Plot</value>
+    </param>
+    <param>
+      <key>samp_rate</key>
+      <value>samp_rate</value>
+    </param>
+    <param>
+      <key>baseband_freq</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>y_per_div</key>
+      <value>10</value>
+    </param>
+    <param>
+      <key>y_divs</key>
+      <value>10</value>
+    </param>
+    <param>
+      <key>ref_level</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>ref_scale</key>
+      <value>2.0</value>
+    </param>
+    <param>
+      <key>fft_size</key>
+      <value>1024</value>
+    </param>
+    <param>
+      <key>fft_rate</key>
+      <value>15</value>
+    </param>
+    <param>
+      <key>peak_hold</key>
+      <value>False</value>
+    </param>
+    <param>
+      <key>average</key>
+      <value>False</value>
+    </param>
+    <param>
+      <key>avg_alpha</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>win</key>
+      <value>None</value>
+    </param>
+    <param>
+      <key>win_size</key>
       <value></value>
     </param>
     <param>
-      <key>value</key>
-      <value>940e6</value>
-    </param>
-    <param>
-      <key>min</key>
-      <value>800e6</value>
-    </param>
-    <param>
-      <key>max</key>
-      <value>1000e6</value>
-    </param>
-    <param>
-      <key>num_steps</key>
-      <value>1000</value>
-    </param>
-    <param>
-      <key>style</key>
-      <value>wx.SL_HORIZONTAL</value>
-    </param>
-    <param>
-      <key>converver</key>
-      <value>float_converter</value>
-    </param>
-    <param>
       <key>grid_pos</key>
       <value></value>
     </param>
@@ -750,12 +742,20 @@
       <value></value>
     </param>
     <param>
+      <key>freqvar</key>
+      <value>None</value>
+    </param>
+    <param>
       <key>alias</key>
       <value></value>
     </param>
     <param>
+      <key>affinity</key>
+      <value></value>
+    </param>
+    <param>
       <key>_coordinate</key>
-      <value>(333, 29)</value>
+      <value>(582, 387)</value>
     </param>
     <param>
       <key>_rotation</key>
@@ -763,75 +763,28 @@
     </param>
   </block>
   <block>
-    <key>variable_slider</key>
+    <key>gsm_receiver_hier</key>
     <param>
       <key>id</key>
-      <value>g</value>
+      <value>gsm_receiver_hier_0</value>
     </param>
     <param>
       <key>_enabled</key>
       <value>True</value>
     </param>
     <param>
-      <key>label</key>
-      <value></value>
+      <key>input_rate</key>
+      <value>samp_rate</value>
     </param>
     <param>
-      <key>value</key>
-      <value>43</value>
+      <key>osr</key>
+      <value>4</value>
     </param>
     <param>
-      <key>min</key>
+      <key>arfcn</key>
       <value>0</value>
     </param>
     <param>
-      <key>max</key>
-      <value>100</value>
-    </param>
-    <param>
-      <key>num_steps</key>
-      <value>100</value>
-    </param>
-    <param>
-      <key>style</key>
-      <value>wx.SL_HORIZONTAL</value>
-    </param>
-    <param>
-      <key>converver</key>
-      <value>float_converter</value>
-    </param>
-    <param>
-      <key>grid_pos</key>
-      <value></value>
-    </param>
-    <param>
-      <key>notebook</key>
-      <value></value>
-    </param>
-    <param>
-      <key>alias</key>
-      <value></value>
-    </param>
-    <param>
-      <key>_coordinate</key>
-      <value>(217, 29)</value>
-    </param>
-    <param>
-      <key>_rotation</key>
-      <value>0</value>
-    </param>
-  </block>
-  <block>
-    <key>gsm_control_channels_decoder</key>
-    <param>
-      <key>id</key>
-      <value>gsm_control_channels_decoder_0</value>
-    </param>
-    <param>
-      <key>_enabled</key>
-      <value>True</value>
-    </param>
-    <param>
       <key>alias</key>
       <value></value>
     </param>
@@ -849,37 +802,60 @@
     </param>
     <param>
       <key>_coordinate</key>
-      <value>(821, 371)</value>
+      <value>(585, 306)</value>
     </param>
     <param>
       <key>_rotation</key>
       <value>0</value>
     </param>
   </block>
-  <connection>
-    <source_block_id>rtlsdr_source_0</source_block_id>
-    <sink_block_id>clk_offset_corrector_0</sink_block_id>
-    <source_key>0</source_key>
-    <sink_key>0</sink_key>
-  </connection>
-  <connection>
-    <source_block_id>gsm_clock_offset_control_0</source_block_id>
-    <sink_block_id>clk_offset_corrector_0</sink_block_id>
-    <source_key>ppm</source_key>
-    <sink_key>ppm_msg</sink_key>
-  </connection>
-  <connection>
-    <source_block_id>clk_offset_corrector_0</source_block_id>
-    <sink_block_id>wxgui_fftsink2_0</sink_block_id>
-    <source_key>0</source_key>
-    <sink_key>0</sink_key>
-  </connection>
-  <connection>
-    <source_block_id>clk_offset_corrector_0</source_block_id>
-    <sink_block_id>gsm_receiver_hier_0</sink_block_id>
-    <source_key>0</source_key>
-    <sink_key>0</sink_key>
-  </connection>
+  <block>
+    <key>clock_offset_corrector</key>
+    <param>
+      <key>id</key>
+      <value>clock_offset_corrector_0</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>ppm</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>samp_rate</key>
+      <value>1625000.0/6.0*4.0</value>
+    </param>
+    <param>
+      <key>fc</key>
+      <value>936.6e6</value>
+    </param>
+    <param>
+      <key>alias</key>
+      <value></value>
+    </param>
+    <param>
+      <key>affinity</key>
+      <value></value>
+    </param>
+    <param>
+      <key>minoutbuf</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>maxoutbuf</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(340, 306)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
   <connection>
     <source_block_id>gsm_receiver_hier_0</source_block_id>
     <sink_block_id>gsm_get_bcch_or_ccch_bursts_0</sink_block_id>
@@ -904,4 +880,28 @@
     <source_key>measurements</source_key>
     <sink_key>measurements</sink_key>
   </connection>
+  <connection>
+    <source_block_id>rtlsdr_source_0</source_block_id>
+    <sink_block_id>clock_offset_corrector_0</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gsm_clock_offset_control_0</source_block_id>
+    <sink_block_id>clock_offset_corrector_0</sink_block_id>
+    <source_key>ppm</source_key>
+    <sink_key>ppm_msg</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>clock_offset_corrector_0</source_block_id>
+    <sink_block_id>wxgui_fftsink2_0</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>clock_offset_corrector_0</source_block_id>
+    <sink_block_id>gsm_receiver_hier_0</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
 </flow_graph>
diff --git a/examples/rtl.py b/examples/rtl.py
new file mode 100755
index 0000000..5e14a91
--- /dev/null
+++ b/examples/rtl.py
@@ -0,0 +1,214 @@
+#!/usr/bin/env python
+##################################################
+# Gnuradio Python Flow Graph
+# Title: Rtl
+# Generated: Wed Aug  6 15:59:37 2014
+##################################################
+
+from gnuradio import eng_notation
+from gnuradio import gr
+from gnuradio import wxgui
+from gnuradio.eng_option import eng_option
+from gnuradio.fft import window
+from gnuradio.filter import firdes
+from gnuradio.wxgui import fftsink2
+from gnuradio.wxgui import forms
+from grc_gnuradio import wxgui as grc_wxgui
+from optparse import OptionParser
+import gsm
+import osmosdr
+import wx
+
+class rtl(grc_wxgui.top_block_gui):
+
+    def __init__(self):
+        grc_wxgui.top_block_gui.__init__(self, title="Rtl")
+        _icon_path = "/home/piotr/.local/share/icons/hicolor/32x32/apps/gnuradio-grc.png"
+        self.SetIcon(wx.Icon(_icon_path, wx.BITMAP_TYPE_ANY))
+
+        ##################################################
+        # Variables
+        ##################################################
+        self.samp_rate = samp_rate = 1000000.026491
+        self.ppm = ppm = 0
+        self.g = g = 43
+        self.fc = fc = 940e6
+
+        ##################################################
+        # Blocks
+        ##################################################
+        _ppm_sizer = wx.BoxSizer(wx.VERTICAL)
+        self._ppm_text_box = forms.text_box(
+        	parent=self.GetWin(),
+        	sizer=_ppm_sizer,
+        	value=self.ppm,
+        	callback=self.set_ppm,
+        	label='ppm',
+        	converter=forms.float_converter(),
+        	proportion=0,
+        )
+        self._ppm_slider = forms.slider(
+        	parent=self.GetWin(),
+        	sizer=_ppm_sizer,
+        	value=self.ppm,
+        	callback=self.set_ppm,
+        	minimum=-50,
+        	maximum=50,
+        	num_steps=100,
+        	style=wx.SL_HORIZONTAL,
+        	cast=float,
+        	proportion=1,
+        )
+        self.Add(_ppm_sizer)
+        _g_sizer = wx.BoxSizer(wx.VERTICAL)
+        self._g_text_box = forms.text_box(
+        	parent=self.GetWin(),
+        	sizer=_g_sizer,
+        	value=self.g,
+        	callback=self.set_g,
+        	label='g',
+        	converter=forms.float_converter(),
+        	proportion=0,
+        )
+        self._g_slider = forms.slider(
+        	parent=self.GetWin(),
+        	sizer=_g_sizer,
+        	value=self.g,
+        	callback=self.set_g,
+        	minimum=0,
+        	maximum=100,
+        	num_steps=100,
+        	style=wx.SL_HORIZONTAL,
+        	cast=float,
+        	proportion=1,
+        )
+        self.Add(_g_sizer)
+        _fc_sizer = wx.BoxSizer(wx.VERTICAL)
+        self._fc_text_box = forms.text_box(
+        	parent=self.GetWin(),
+        	sizer=_fc_sizer,
+        	value=self.fc,
+        	callback=self.set_fc,
+        	label='fc',
+        	converter=forms.float_converter(),
+        	proportion=0,
+        )
+        self._fc_slider = forms.slider(
+        	parent=self.GetWin(),
+        	sizer=_fc_sizer,
+        	value=self.fc,
+        	callback=self.set_fc,
+        	minimum=800e6,
+        	maximum=1000e6,
+        	num_steps=1000,
+        	style=wx.SL_HORIZONTAL,
+        	cast=float,
+        	proportion=1,
+        )
+        self.Add(_fc_sizer)
+        self.wxgui_fftsink2_0 = fftsink2.fft_sink_c(
+        	self.GetWin(),
+        	baseband_freq=0,
+        	y_per_div=10,
+        	y_divs=10,
+        	ref_level=0,
+        	ref_scale=2.0,
+        	sample_rate=samp_rate,
+        	fft_size=1024,
+        	fft_rate=15,
+        	average=False,
+        	avg_alpha=None,
+        	title="FFT Plot",
+        	peak_hold=False,
+        )
+        self.Add(self.wxgui_fftsink2_0.win)
+        self.rtlsdr_source_0 = osmosdr.source( args="numchan=" + str(1) + " " + "" )
+        self.rtlsdr_source_0.set_sample_rate(samp_rate)
+        self.rtlsdr_source_0.set_center_freq(fc, 0)
+        self.rtlsdr_source_0.set_freq_corr(ppm, 0)
+        self.rtlsdr_source_0.set_dc_offset_mode(0, 0)
+        self.rtlsdr_source_0.set_iq_balance_mode(0, 0)
+        self.rtlsdr_source_0.set_gain_mode(True, 0)
+        self.rtlsdr_source_0.set_gain(g, 0)
+        self.rtlsdr_source_0.set_if_gain(20, 0)
+        self.rtlsdr_source_0.set_bb_gain(20, 0)
+        self.rtlsdr_source_0.set_antenna("", 0)
+        self.rtlsdr_source_0.set_bandwidth(250e3, 0)
+          
+        self.gsm_receiver_hier_0 = gsm.receiver_hier(samp_rate, 4)
+        self.gsm_message_printer_0 = gsm.message_printer()
+        self.gsm_get_bcch_or_ccch_bursts_0 = gsm.get_bcch_or_ccch_bursts(2)
+        self.gsm_control_channels_decoder_0 = gsm.control_channels_decoder()
+        self.gsm_clock_offset_control_0 = gsm.clock_offset_control(fc, samp_rate)
+        self.clock_offset_corrector_0 = gsm.clock_offset_corrector(
+            ppm=0,
+            samp_rate=1625000.0/6.0*4.0,
+            fc=936.6e6,
+        )
+
+        ##################################################
+        # Connections
+        ##################################################
+        self.connect((self.rtlsdr_source_0, 0), (self.clock_offset_corrector_0, 0))
+        self.connect((self.clock_offset_corrector_0, 0), (self.wxgui_fftsink2_0, 0))
+        self.connect((self.clock_offset_corrector_0, 0), (self.gsm_receiver_hier_0, 0))
+
+        ##################################################
+        # Asynch Message Connections
+        ##################################################
+        self.msg_connect(self.gsm_receiver_hier_0, "bursts", self.gsm_get_bcch_or_ccch_bursts_0, "bursts")
+        self.msg_connect(self.gsm_get_bcch_or_ccch_bursts_0, "bursts", self.gsm_control_channels_decoder_0, "bursts")
+        self.msg_connect(self.gsm_control_channels_decoder_0, "msgs", self.gsm_message_printer_0, "msgs")
+        self.msg_connect(self.gsm_receiver_hier_0, "measurements", self.gsm_clock_offset_control_0, "measurements")
+        self.msg_connect(self.gsm_clock_offset_control_0, "ppm", self.clock_offset_corrector_0, "ppm_msg")
+
+
+    def get_samp_rate(self):
+        return self.samp_rate
+
+    def set_samp_rate(self, samp_rate):
+        self.samp_rate = samp_rate
+        self.rtlsdr_source_0.set_sample_rate(self.samp_rate)
+        self.wxgui_fftsink2_0.set_sample_rate(self.samp_rate)
+
+    def get_ppm(self):
+        return self.ppm
+
+    def set_ppm(self, ppm):
+        self.ppm = ppm
+        self._ppm_slider.set_value(self.ppm)
+        self._ppm_text_box.set_value(self.ppm)
+        self.rtlsdr_source_0.set_freq_corr(self.ppm, 0)
+
+    def get_g(self):
+        return self.g
+
+    def set_g(self, g):
+        self.g = g
+        self._g_slider.set_value(self.g)
+        self._g_text_box.set_value(self.g)
+        self.rtlsdr_source_0.set_gain(self.g, 0)
+
+    def get_fc(self):
+        return self.fc
+
+    def set_fc(self, fc):
+        self.fc = fc
+        self._fc_slider.set_value(self.fc)
+        self._fc_text_box.set_value(self.fc)
+        self.rtlsdr_source_0.set_center_freq(self.fc, 0)
+
+if __name__ == '__main__':
+    import ctypes
+    import sys
+    if sys.platform.startswith('linux'):
+        try:
+            x11 = ctypes.cdll.LoadLibrary('libX11.so')
+            x11.XInitThreads()
+        except:
+            print "Warning: failed to XInitThreads()"
+    parser = OptionParser(option_class=eng_option, usage="%prog: [options]")
+    (options, args) = parser.parse_args()
+    tb = rtl()
+    tb.Start(True)
+    tb.Wait()