Merged changeset r9285:9377 from jblum/grc into trunk, with distcheck fixes

and local modifications.

Integrates previously separate GNU Radio Companion into top-level component
'grc'.  (Josh Blum)


git-svn-id: http://gnuradio.org/svn/gnuradio/trunk@9378 221aa14e-8319-0410-a670-987f0aec2ac5

13 files changed, 2919 insertions, 0 deletions

diff --git a/grc/examples/Makefile.am b/grc/examples/Makefile.am
new file mode 100644
index 000000000..9bba14bc9
--- /dev/null
+++ b/grc/examples/Makefile.am
@@ -0,0 +1,28 @@
+#
+# Copyright 2008 Free Software Foundation, Inc.
+#
+# This file is part of GNU Radio
+#
+# GNU Radio is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3, or (at your option)
+# any later version.
+#
+# GNU Radio is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with GNU Radio; see the file COPYING.  If not, write to
+# the Free Software Foundation, Inc., 51 Franklin Street,
+# Boston, MA 02110-1301, USA.
+#
+
+include $(top_srcdir)/grc/Makefile.common
+
+SUBDIRS = \
+	audio \
+	simple \
+	usrp \
+	xmlrpc
diff --git a/grc/examples/audio/Makefile.am b/grc/examples/audio/Makefile.am
new file mode 100644
index 000000000..78800edcc
--- /dev/null
+++ b/grc/examples/audio/Makefile.am
@@ -0,0 +1,26 @@
+#
+# Copyright 2008 Free Software Foundation, Inc.
+#
+# This file is part of GNU Radio
+#
+# GNU Radio is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3, or (at your option)
+# any later version.
+#
+# GNU Radio is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with GNU Radio; see the file COPYING.  If not, write to
+# the Free Software Foundation, Inc., 51 Franklin Street,
+# Boston, MA 02110-1301, USA.
+#
+
+include $(top_srcdir)/grc/Makefile.common
+
+datadir = $(grc_examples_prefix)/audio
+
+EXTRA_DIST = dial_tone.grc
diff --git a/grc/examples/audio/dial_tone.grc b/grc/examples/audio/dial_tone.grc
new file mode 100644
index 000000000..6f96d9748
--- /dev/null
+++ b/grc/examples/audio/dial_tone.grc
@@ -0,0 +1,375 @@
+<?xml version='1.0' encoding='ASCII'?>
+<flow_graph>
+  <timestamp>Thu Jul 24 14:27:48 2008</timestamp>
+  <block>
+    <key>options</key>
+    <param>
+      <key>id</key>
+      <value>dial_tone</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>title</key>
+      <value>Dial Tone</value>
+    </param>
+    <param>
+      <key>author</key>
+      <value>Example</value>
+    </param>
+    <param>
+      <key>description</key>
+      <value>example flow graph</value>
+    </param>
+    <param>
+      <key>window_size</key>
+      <value>1280, 1024</value>
+    </param>
+    <param>
+      <key>generate_options</key>
+      <value>wx_gui</value>
+    </param>
+    <param>
+      <key>category</key>
+      <value>Custom</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(10, 10)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gr_add_vxx</key>
+    <param>
+      <key>id</key>
+      <value>gr_add_vxx</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>float</value>
+    </param>
+    <param>
+      <key>num_inputs</key>
+      <value>3</value>
+    </param>
+    <param>
+      <key>vlen</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(513, 277)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>audio_sink</key>
+    <param>
+      <key>id</key>
+      <value>audio_sink</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>samp_rate</key>
+      <value>32000</value>
+    </param>
+    <param>
+      <key>device_name</key>
+      <value/>
+    </param>
+    <param>
+      <key>ok_to_block</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>num_inputs</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(699, 112)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gr_noise_source_x</key>
+    <param>
+      <key>id</key>
+      <value>gr_noise_source_x</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>float</value>
+    </param>
+    <param>
+      <key>noise_type</key>
+      <value>gr.GR_GAUSSIAN</value>
+    </param>
+    <param>
+      <key>amp</key>
+      <value>noise</value>
+    </param>
+    <param>
+      <key>seed</key>
+      <value>42</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(238, 380)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gr_sig_source_x</key>
+    <param>
+      <key>id</key>
+      <value>gr_sig_source_x</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>float</value>
+    </param>
+    <param>
+      <key>samp_rate</key>
+      <value>samp_rate</value>
+    </param>
+    <param>
+      <key>waveform</key>
+      <value>gr.GR_COS_WAVE</value>
+    </param>
+    <param>
+      <key>freq</key>
+      <value>440</value>
+    </param>
+    <param>
+      <key>amp</key>
+      <value>ampl</value>
+    </param>
+    <param>
+      <key>offset</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(240, 208)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gr_sig_source_x</key>
+    <param>
+      <key>id</key>
+      <value>gr_sig_source_x0</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>float</value>
+    </param>
+    <param>
+      <key>samp_rate</key>
+      <value>samp_rate</value>
+    </param>
+    <param>
+      <key>waveform</key>
+      <value>gr.GR_COS_WAVE</value>
+    </param>
+    <param>
+      <key>freq</key>
+      <value>350</value>
+    </param>
+    <param>
+      <key>amp</key>
+      <value>ampl</value>
+    </param>
+    <param>
+      <key>offset</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(240, 38)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>variable_slider</key>
+    <param>
+      <key>id</key>
+      <value>ampl</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>label</key>
+      <value>Volume</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>.4</value>
+    </param>
+    <param>
+      <key>min</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>max</key>
+      <value>.5</value>
+    </param>
+    <param>
+      <key>num_steps</key>
+      <value>100</value>
+    </param>
+    <param>
+      <key>slider_type</key>
+      <value>horizontal</value>
+    </param>
+    <param>
+      <key>grid_pos</key>
+      <value>0, 0, 1, 2</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(634, 413)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>variable_slider</key>
+    <param>
+      <key>id</key>
+      <value>noise</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>label</key>
+      <value>Noise</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>.005</value>
+    </param>
+    <param>
+      <key>min</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>max</key>
+      <value>.2</value>
+    </param>
+    <param>
+      <key>num_steps</key>
+      <value>100</value>
+    </param>
+    <param>
+      <key>slider_type</key>
+      <value>horizontal</value>
+    </param>
+    <param>
+      <key>grid_pos</key>
+      <value>1, 0, 1, 2</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(443, 412)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>variable</key>
+    <param>
+      <key>id</key>
+      <value>samp_rate</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>32000</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(11, 171)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <connection>
+    <source_block_id>gr_sig_source_x0</source_block_id>
+    <sink_block_id>gr_add_vxx</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_sig_source_x</source_block_id>
+    <sink_block_id>gr_add_vxx</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>1</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_noise_source_x</source_block_id>
+    <sink_block_id>gr_add_vxx</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>2</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_add_vxx</source_block_id>
+    <sink_block_id>audio_sink</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+</flow_graph>
\ No newline at end of file
diff --git a/grc/examples/simple/Makefile.am b/grc/examples/simple/Makefile.am
new file mode 100644
index 000000000..a2fcd614e
--- /dev/null
+++ b/grc/examples/simple/Makefile.am
@@ -0,0 +1,26 @@
+#
+# Copyright 2008 Free Software Foundation, Inc.
+#
+# This file is part of GNU Radio
+#
+# GNU Radio is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3, or (at your option)
+# any later version.
+#
+# GNU Radio is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with GNU Radio; see the file COPYING.  If not, write to
+# the Free Software Foundation, Inc., 51 Franklin Street,
+# Boston, MA 02110-1301, USA.
+#
+
+include $(top_srcdir)/grc/Makefile.common
+
+datadir = $(grc_examples_prefix)/simple
+
+EXTRA_DIST = ber_simulation.grc
diff --git a/grc/examples/simple/ber_simulation.grc b/grc/examples/simple/ber_simulation.grc
new file mode 100644
index 000000000..0e4ce64ed
--- /dev/null
+++ b/grc/examples/simple/ber_simulation.grc
@@ -0,0 +1,540 @@
+<?xml version='1.0' encoding='ASCII'?>
+<flow_graph>
+  <timestamp>Thu Jul 24 14:28:06 2008</timestamp>
+  <block>
+    <key>options</key>
+    <param>
+      <key>id</key>
+      <value>ber_sim</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>title</key>
+      <value>BER Simulation</value>
+    </param>
+    <param>
+      <key>author</key>
+      <value>Example</value>
+    </param>
+    <param>
+      <key>description</key>
+      <value>Adjust the noise and constellation... see what happens!</value>
+    </param>
+    <param>
+      <key>window_size</key>
+      <value>1280, 1024</value>
+    </param>
+    <param>
+      <key>generate_options</key>
+      <value>wx_gui</value>
+    </param>
+    <param>
+      <key>category</key>
+      <value>Custom</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(16, 10)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gr_add_vxx</key>
+    <param>
+      <key>id</key>
+      <value>gr_add_vxx</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>complex</value>
+    </param>
+    <param>
+      <key>num_inputs</key>
+      <value>2</value>
+    </param>
+    <param>
+      <key>vlen</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(652, 395)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>wxgui_constellationsink2</key>
+    <param>
+      <key>id</key>
+      <value>wxgui_constellationsink2</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>title</key>
+      <value>"Constellation: "+str(const)</value>
+    </param>
+    <param>
+      <key>samp_rate</key>
+      <value>samp_rate</value>
+    </param>
+    <param>
+      <key>frame_decim</key>
+      <value>15</value>
+    </param>
+    <param>
+      <key>marker</key>
+      <value>set_format_plus</value>
+    </param>
+    <param>
+      <key>grid_pos</key>
+      <value>2, 0, 1, 1</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(907, 334)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gr_noise_source_x</key>
+    <param>
+      <key>id</key>
+      <value>gr_noise_source_x</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>complex</value>
+    </param>
+    <param>
+      <key>noise_type</key>
+      <value>gr.GR_GAUSSIAN</value>
+    </param>
+    <param>
+      <key>amp</key>
+      <value>noise</value>
+    </param>
+    <param>
+      <key>seed</key>
+      <value>42</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(235, 379)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gr_chunks_to_symbols_xx</key>
+    <param>
+      <key>id</key>
+      <value>gr_chunks_to_symbols_xx</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>in_type</key>
+      <value>byte</value>
+    </param>
+    <param>
+      <key>out_type</key>
+      <value>complex</value>
+    </param>
+    <param>
+      <key>symbol_table</key>
+      <value>const</value>
+    </param>
+    <param>
+      <key>dimension</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(360, 237)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>wxgui_numbersink2</key>
+    <param>
+      <key>id</key>
+      <value>wxgui_numbersink2</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>float</value>
+    </param>
+    <param>
+      <key>title</key>
+      <value>BER</value>
+    </param>
+    <param>
+      <key>units</key>
+      <value>%</value>
+    </param>
+    <param>
+      <key>samp_rate</key>
+      <value>samp_rate</value>
+    </param>
+    <param>
+      <key>base_value</key>
+      <value>0.0</value>
+    </param>
+    <param>
+      <key>min_value</key>
+      <value>0.0</value>
+    </param>
+    <param>
+      <key>max_value</key>
+      <value>1.0</value>
+    </param>
+    <param>
+      <key>factor</key>
+      <value>100</value>
+    </param>
+    <param>
+      <key>decimal_places</key>
+      <value>4</value>
+    </param>
+    <param>
+      <key>ref_level</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>number_rate</key>
+      <value>15</value>
+    </param>
+    <param>
+      <key>avg_alpha</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>options</key>
+      <value>none</value>
+    </param>
+    <param>
+      <key>show_gauge</key>
+      <value>False</value>
+    </param>
+    <param>
+      <key>grid_pos</key>
+      <value>1, 0, 1, 1</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(1062, 11)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gr_throttle</key>
+    <param>
+      <key>id</key>
+      <value>gr_throttle</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>byte</value>
+    </param>
+    <param>
+      <key>samples_per_second</key>
+      <value>samp_rate</value>
+    </param>
+    <param>
+      <key>vlen</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(397, 27)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>blks2_error_rate</key>
+    <param>
+      <key>id</key>
+      <value>blks2_error_rate</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>"BER"</value>
+    </param>
+    <param>
+      <key>win_size</key>
+      <value>1000000</value>
+    </param>
+    <param>
+      <key>bits_per_symbol</key>
+      <value>int(math.log(len(const))/math.log(2))</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(670, 41)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gr_constellation_decoder_cb</key>
+    <param>
+      <key>id</key>
+      <value>gr_constellation_decoder_cb</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>sym_position</key>
+      <value>const</value>
+    </param>
+    <param>
+      <key>sym_value_out</key>
+      <value>range(len(const))</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(708, 224)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>random_source_x</key>
+    <param>
+      <key>id</key>
+      <value>random_source_x</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>byte</value>
+    </param>
+    <param>
+      <key>min</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>max</key>
+      <value>len(const)</value>
+    </param>
+    <param>
+      <key>num_samps</key>
+      <value>1000000</value>
+    </param>
+    <param>
+      <key>repeat</key>
+      <value>False</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(15, 244)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>variable</key>
+    <param>
+      <key>id</key>
+      <value>noise</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>.25</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(18, 386)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>variable</key>
+    <param>
+      <key>id</key>
+      <value>const</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>1+1j, 1-1j, -1-1j, -1+1j</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(16, 461)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>variable</key>
+    <param>
+      <key>id</key>
+      <value>samp_rate</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>50e3</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(20, 168)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>import</key>
+    <param>
+      <key>id</key>
+      <value>import</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>import</key>
+      <value>import math</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(138, 168)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <connection>
+    <source_block_id>blks2_error_rate</source_block_id>
+    <sink_block_id>wxgui_numbersink2</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_throttle</source_block_id>
+    <sink_block_id>blks2_error_rate</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_constellation_decoder_cb</source_block_id>
+    <sink_block_id>blks2_error_rate</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>1</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_add_vxx</source_block_id>
+    <sink_block_id>gr_constellation_decoder_cb</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_chunks_to_symbols_xx</source_block_id>
+    <sink_block_id>gr_add_vxx</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_noise_source_x</source_block_id>
+    <sink_block_id>gr_add_vxx</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>1</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_add_vxx</source_block_id>
+    <sink_block_id>wxgui_constellationsink2</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>random_source_x</source_block_id>
+    <sink_block_id>gr_throttle</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>random_source_x</source_block_id>
+    <sink_block_id>gr_chunks_to_symbols_xx</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+</flow_graph>
\ No newline at end of file
diff --git a/grc/examples/usrp/Makefile.am b/grc/examples/usrp/Makefile.am
new file mode 100644
index 000000000..9ad96c915
--- /dev/null
+++ b/grc/examples/usrp/Makefile.am
@@ -0,0 +1,28 @@
+#
+# Copyright 2008 Free Software Foundation, Inc.
+#
+# This file is part of GNU Radio
+#
+# GNU Radio is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3, or (at your option)
+# any later version.
+#
+# GNU Radio is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with GNU Radio; see the file COPYING.  If not, write to
+# the Free Software Foundation, Inc., 51 Franklin Street,
+# Boston, MA 02110-1301, USA.
+#
+
+include $(top_srcdir)/grc/Makefile.common
+
+datadir = $(grc_examples_prefix)/usrp
+
+EXTRA_DIST = \
+	usrp_two_tone_loopback.grc \
+	usrp_wbfm_receive.grc
diff --git a/grc/examples/usrp/usrp_two_tone_loopback.grc b/grc/examples/usrp/usrp_two_tone_loopback.grc
new file mode 100644
index 000000000..ccbe190ec
--- /dev/null
+++ b/grc/examples/usrp/usrp_two_tone_loopback.grc
@@ -0,0 +1,675 @@
+<?xml version='1.0' encoding='ASCII'?>
+<flow_graph>
+  <timestamp>Thu Jul 24 14:27:46 2008</timestamp>
+  <block>
+    <key>options</key>
+    <param>
+      <key>id</key>
+      <value>top_block</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>title</key>
+      <value>USRP Loopback - 2 Tone</value>
+    </param>
+    <param>
+      <key>author</key>
+      <value>Example</value>
+    </param>
+    <param>
+      <key>description</key>
+      <value>Loopback test with basic rx and basic tx</value>
+    </param>
+    <param>
+      <key>window_size</key>
+      <value>1280, 1024</value>
+    </param>
+    <param>
+      <key>generate_options</key>
+      <value>wx_gui</value>
+    </param>
+    <param>
+      <key>category</key>
+      <value>Custom</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(10, 10)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>usrp_simple_source_x</key>
+    <param>
+      <key>id</key>
+      <value>usrp_simple_source_x</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>complex</value>
+    </param>
+    <param>
+      <key>number</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>subdev_spec</key>
+      <value>None</value>
+    </param>
+    <param>
+      <key>frequency</key>
+      <value>tun_freq</value>
+    </param>
+    <param>
+      <key>decimation</key>
+      <value>200</value>
+    </param>
+    <param>
+      <key>gain</key>
+      <value>20</value>
+    </param>
+    <param>
+      <key>mux</key>
+      <value>0x0</value>
+    </param>
+    <param>
+      <key>auto_tr</key>
+      <value>None</value>
+    </param>
+    <param>
+      <key>rx_ant</key>
+      <value>None</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(578, 319)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>wxgui_fftsink2</key>
+    <param>
+      <key>id</key>
+      <value>wxgui_fftsink2</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>8</value>
+    </param>
+    <param>
+      <key>ref_level</key>
+      <value>100</value>
+    </param>
+    <param>
+      <key>fft_size</key>
+      <value>512*2</value>
+    </param>
+    <param>
+      <key>fft_rate</key>
+      <value>15</value>
+    </param>
+    <param>
+      <key>avg_alpha</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>average</key>
+      <value>False</value>
+    </param>
+    <param>
+      <key>peak_hold</key>
+      <value>False</value>
+    </param>
+    <param>
+      <key>grid_pos</key>
+      <value>1, 2, 2, 4</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(845, 228)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>variable_slider</key>
+    <param>
+      <key>id</key>
+      <value>tone2</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>label</key>
+      <value>Tone 2</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>75e3</value>
+    </param>
+    <param>
+      <key>min</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>max</key>
+      <value>150000</value>
+    </param>
+    <param>
+      <key>num_steps</key>
+      <value>100</value>
+    </param>
+    <param>
+      <key>slider_type</key>
+      <value>horizontal</value>
+    </param>
+    <param>
+      <key>grid_pos</key>
+      <value>0, 4, 1, 2</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(397, 478)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>variable_slider</key>
+    <param>
+      <key>id</key>
+      <value>tone1</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>label</key>
+      <value>Tone 1</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>50e3</value>
+    </param>
+    <param>
+      <key>min</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>max</key>
+      <value>150000</value>
+    </param>
+    <param>
+      <key>num_steps</key>
+      <value>100</value>
+    </param>
+    <param>
+      <key>slider_type</key>
+      <value>horizontal</value>
+    </param>
+    <param>
+      <key>grid_pos</key>
+      <value>0, 2, 1, 2</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(220, 475)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>variable_slider</key>
+    <param>
+      <key>id</key>
+      <value>noise_ampl</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>label</key>
+      <value>Noise Ampl</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>2000</value>
+    </param>
+    <param>
+      <key>min</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>max</key>
+      <value>5000</value>
+    </param>
+    <param>
+      <key>num_steps</key>
+      <value>100</value>
+    </param>
+    <param>
+      <key>slider_type</key>
+      <value>vertical</value>
+    </param>
+    <param>
+      <key>grid_pos</key>
+      <value>1, 1, 2, 1</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(20, 243)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>variable_slider</key>
+    <param>
+      <key>id</key>
+      <value>tone_ampl</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>label</key>
+      <value>Tone Ampl</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>5000</value>
+    </param>
+    <param>
+      <key>min</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>max</key>
+      <value>5000</value>
+    </param>
+    <param>
+      <key>num_steps</key>
+      <value>100</value>
+    </param>
+    <param>
+      <key>slider_type</key>
+      <value>vertical</value>
+    </param>
+    <param>
+      <key>grid_pos</key>
+      <value>1, 0, 2, 1</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(21, 422)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>usrp_simple_sink_x</key>
+    <param>
+      <key>id</key>
+      <value>usrp_simple_sink_x</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>complex</value>
+    </param>
+    <param>
+      <key>number</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>subdev_spec</key>
+      <value>None</value>
+    </param>
+    <param>
+      <key>frequency</key>
+      <value>tun_freq</value>
+    </param>
+    <param>
+      <key>interpolation</key>
+      <value>400</value>
+    </param>
+    <param>
+      <key>gain</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>mux</key>
+      <value>0x0</value>
+    </param>
+    <param>
+      <key>auto_tr</key>
+      <value>None</value>
+    </param>
+    <param>
+      <key>tx_enb</key>
+      <value>None</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(835, 5)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gr_float_to_complex</key>
+    <param>
+      <key>id</key>
+      <value>gr_float_to_complex</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(634, 226)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gr_add_vxx</key>
+    <param>
+      <key>id</key>
+      <value>gr_add_vxx</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>float</value>
+    </param>
+    <param>
+      <key>num_inputs</key>
+      <value>3</value>
+    </param>
+    <param>
+      <key>vlen</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(528, 78)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gr_sig_source_x</key>
+    <param>
+      <key>id</key>
+      <value>gr_sig_source_x</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>float</value>
+    </param>
+    <param>
+      <key>samp_rate</key>
+      <value>samp_rate</value>
+    </param>
+    <param>
+      <key>waveform</key>
+      <value>gr.GR_COS_WAVE</value>
+    </param>
+    <param>
+      <key>freq</key>
+      <value>tone1</value>
+    </param>
+    <param>
+      <key>amp</key>
+      <value>tone_ampl</value>
+    </param>
+    <param>
+      <key>offset</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(258, 20)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gr_sig_source_x</key>
+    <param>
+      <key>id</key>
+      <value>gr_sig_source_x0</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>float</value>
+    </param>
+    <param>
+      <key>samp_rate</key>
+      <value>samp_rate</value>
+    </param>
+    <param>
+      <key>waveform</key>
+      <value>gr.GR_COS_WAVE</value>
+    </param>
+    <param>
+      <key>freq</key>
+      <value>tone2</value>
+    </param>
+    <param>
+      <key>amp</key>
+      <value>tone_ampl</value>
+    </param>
+    <param>
+      <key>offset</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(255, 179)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gr_noise_source_x</key>
+    <param>
+      <key>id</key>
+      <value>gr_noise_source_x</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>float</value>
+    </param>
+    <param>
+      <key>noise_type</key>
+      <value>gr.GR_GAUSSIAN</value>
+    </param>
+    <param>
+      <key>amp</key>
+      <value>noise_ampl</value>
+    </param>
+    <param>
+      <key>seed</key>
+      <value>42</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(257, 337)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>variable</key>
+    <param>
+      <key>id</key>
+      <value>samp_rate</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>64e6/200</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(9, 166)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>variable</key>
+    <param>
+      <key>id</key>
+      <value>tun_freq</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>int(100e6)</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(116, 166)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <connection>
+    <source_block_id>gr_sig_source_x</source_block_id>
+    <sink_block_id>gr_add_vxx</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_sig_source_x0</source_block_id>
+    <sink_block_id>gr_add_vxx</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>1</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_noise_source_x</source_block_id>
+    <sink_block_id>gr_add_vxx</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>2</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>usrp_simple_source_x</source_block_id>
+    <sink_block_id>wxgui_fftsink2</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_float_to_complex</source_block_id>
+    <sink_block_id>usrp_simple_sink_x</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_add_vxx</source_block_id>
+    <sink_block_id>gr_float_to_complex</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_add_vxx</source_block_id>
+    <sink_block_id>gr_float_to_complex</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>1</sink_key>
+  </connection>
+</flow_graph>
\ No newline at end of file
diff --git a/grc/examples/usrp/usrp_wbfm_receive.grc b/grc/examples/usrp/usrp_wbfm_receive.grc
new file mode 100644
index 000000000..7fb621241
--- /dev/null
+++ b/grc/examples/usrp/usrp_wbfm_receive.grc
@@ -0,0 +1,454 @@
+<?xml version='1.0' encoding='ASCII'?>
+<flow_graph>
+  <timestamp>Thu Jul 24 14:27:45 2008</timestamp>
+  <block>
+    <key>options</key>
+    <param>
+      <key>id</key>
+      <value>top_block</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>title</key>
+      <value>USRP WBFM Receive</value>
+    </param>
+    <param>
+      <key>author</key>
+      <value>Example</value>
+    </param>
+    <param>
+      <key>description</key>
+      <value>WBFM Receive with Basic RX or TV RX</value>
+    </param>
+    <param>
+      <key>window_size</key>
+      <value>1280, 1024</value>
+    </param>
+    <param>
+      <key>generate_options</key>
+      <value>wx_gui</value>
+    </param>
+    <param>
+      <key>category</key>
+      <value>Custom</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(10, 10)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>usrp_simple_source_x</key>
+    <param>
+      <key>id</key>
+      <value>usrp_simple_source_x</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>complex</value>
+    </param>
+    <param>
+      <key>number</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>subdev_spec</key>
+      <value>None</value>
+    </param>
+    <param>
+      <key>frequency</key>
+      <value>(freq+fine)*1e6</value>
+    </param>
+    <param>
+      <key>decimation</key>
+      <value>decim</value>
+    </param>
+    <param>
+      <key>gain</key>
+      <value>20</value>
+    </param>
+    <param>
+      <key>mux</key>
+      <value>0x0</value>
+    </param>
+    <param>
+      <key>auto_tr</key>
+      <value>None</value>
+    </param>
+    <param>
+      <key>rx_ant</key>
+      <value>None</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(277, 29)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>variable_slider</key>
+    <param>
+      <key>id</key>
+      <value>fine</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>label</key>
+      <value>Fine Freq</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>min</key>
+      <value>-.1</value>
+    </param>
+    <param>
+      <key>max</key>
+      <value>.1</value>
+    </param>
+    <param>
+      <key>num_steps</key>
+      <value>100</value>
+    </param>
+    <param>
+      <key>slider_type</key>
+      <value>horizontal</value>
+    </param>
+    <param>
+      <key>grid_pos</key>
+      <value>0, 2, 1, 2</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(275, 246)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>blks2_wfm_rcv</key>
+    <param>
+      <key>id</key>
+      <value>blks2_wfm_rcv</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>quad_rate</key>
+      <value>64e6/decim</value>
+    </param>
+    <param>
+      <key>audio_decimation</key>
+      <value>10</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(510, 37)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>audio_sink</key>
+    <param>
+      <key>id</key>
+      <value>audio_sink</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>samp_rate</key>
+      <value>32000</value>
+    </param>
+    <param>
+      <key>device_name</key>
+      <value/>
+    </param>
+    <param>
+      <key>ok_to_block</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>num_inputs</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(703, 241)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>180</value>
+    </param>
+  </block>
+  <block>
+    <key>gr_multiply_const_vxx</key>
+    <param>
+      <key>id</key>
+      <value>gr_multiply_const_vxx</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>float</value>
+    </param>
+    <param>
+      <key>const</key>
+      <value>volume</value>
+    </param>
+    <param>
+      <key>vlen</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(764, 55)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>wxgui_fftsink2</key>
+    <param>
+      <key>id</key>
+      <value>wxgui_fftsink2</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>64e6/decim</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>8</value>
+    </param>
+    <param>
+      <key>ref_level</key>
+      <value>50</value>
+    </param>
+    <param>
+      <key>fft_size</key>
+      <value>512</value>
+    </param>
+    <param>
+      <key>fft_rate</key>
+      <value>15</value>
+    </param>
+    <param>
+      <key>avg_alpha</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>average</key>
+      <value>False</value>
+    </param>
+    <param>
+      <key>peak_hold</key>
+      <value>False</value>
+    </param>
+    <param>
+      <key>grid_pos</key>
+      <value>2, 0, 2, 4</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(512, 191)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>variable_slider</key>
+    <param>
+      <key>id</key>
+      <value>volume</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>label</key>
+      <value>Volume</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>min</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>max</key>
+      <value>10</value>
+    </param>
+    <param>
+      <key>num_steps</key>
+      <value>100</value>
+    </param>
+    <param>
+      <key>slider_type</key>
+      <value>horizontal</value>
+    </param>
+    <param>
+      <key>grid_pos</key>
+      <value>1, 1, 1, 2</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(991, 40)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>variable_slider</key>
+    <param>
+      <key>id</key>
+      <value>freq</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>label</key>
+      <value>Frequency</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>100</value>
+    </param>
+    <param>
+      <key>min</key>
+      <value>87.5</value>
+    </param>
+    <param>
+      <key>max</key>
+      <value>108.0</value>
+    </param>
+    <param>
+      <key>num_steps</key>
+      <value>1000</value>
+    </param>
+    <param>
+      <key>slider_type</key>
+      <value>horizontal</value>
+    </param>
+    <param>
+      <key>grid_pos</key>
+      <value>0, 0, 1, 2</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(104, 243)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>variable</key>
+    <param>
+      <key>id</key>
+      <value>decim</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>200</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(14, 173)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <connection>
+    <source_block_id>usrp_simple_source_x</source_block_id>
+    <sink_block_id>blks2_wfm_rcv</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>usrp_simple_source_x</source_block_id>
+    <sink_block_id>wxgui_fftsink2</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>blks2_wfm_rcv</source_block_id>
+    <sink_block_id>gr_multiply_const_vxx</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_multiply_const_vxx</source_block_id>
+    <sink_block_id>audio_sink</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+</flow_graph>
\ No newline at end of file
diff --git a/grc/examples/xmlrpc/Makefile.am b/grc/examples/xmlrpc/Makefile.am
new file mode 100644
index 000000000..68ecbdd9b
--- /dev/null
+++ b/grc/examples/xmlrpc/Makefile.am
@@ -0,0 +1,30 @@
+#
+# Copyright 2008 Free Software Foundation, Inc.
+#
+# This file is part of GNU Radio
+#
+# GNU Radio is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3, or (at your option)
+# any later version.
+#
+# GNU Radio is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with GNU Radio; see the file COPYING.  If not, write to
+# the Free Software Foundation, Inc., 51 Franklin Street,
+# Boston, MA 02110-1301, USA.
+#
+
+include $(top_srcdir)/grc/Makefile.common
+
+datadir = $(grc_examples_prefix)/xmlrpc
+
+EXTRA_DIST = \
+	readme.txt \
+	xmlrpc_client.grc \
+	xmlrpc_client_script.py\ 
+	xmlrpc_server.grc
diff --git a/grc/examples/xmlrpc/readme.txt b/grc/examples/xmlrpc/readme.txt
new file mode 100644
index 000000000..c1f87c1cb
--- /dev/null
+++ b/grc/examples/xmlrpc/readme.txt
@@ -0,0 +1,18 @@
+##################################################
+# XMLRPC example
+##################################################
+
+XMLRPC allows software to make remote function calls over http. 
+In the case of GRC, one can use XMLRPC to modify variables in a running flow graph.
+See http://www.xmlrpc.com/
+
+--- Server Example ---
+Place an "XMLRPC Server" block inside of any flow graph. 
+The server will provide set functions for every variable in the flow graph.
+If a variable is called "freq", the server will provide a function set_freq(new_freq).
+Run the server example and experiment with the example client script.
+
+-- Client Example --
+The "XMLRPC Client" block will give a variable control over one remove function.
+In the example client, there is one client block and gui control per variable.
+This technique can be used to remotely control a flow graph, perhaps running on a non-gui machine.
diff --git a/grc/examples/xmlrpc/xmlrpc_client.grc b/grc/examples/xmlrpc/xmlrpc_client.grc
new file mode 100644
index 000000000..3bb4e7ed3
--- /dev/null
+++ b/grc/examples/xmlrpc/xmlrpc_client.grc
@@ -0,0 +1,312 @@
+<?xml version='1.0' encoding='ASCII'?>
+<flow_graph>
+  <timestamp>Thu Jul 24 14:27:44 2008</timestamp>
+  <block>
+    <key>options</key>
+    <param>
+      <key>id</key>
+      <value>client_block</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>title</key>
+      <value>XMLRPC Client</value>
+    </param>
+    <param>
+      <key>author</key>
+      <value>Example</value>
+    </param>
+    <param>
+      <key>description</key>
+      <value>example flow graph</value>
+    </param>
+    <param>
+      <key>window_size</key>
+      <value>1280, 1024</value>
+    </param>
+    <param>
+      <key>generate_options</key>
+      <value>wx_gui</value>
+    </param>
+    <param>
+      <key>category</key>
+      <value>Custom</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(10, 10)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>xmlrpc_client</key>
+    <param>
+      <key>id</key>
+      <value>xmlrpc_client0</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>addr</key>
+      <value>localhost</value>
+    </param>
+    <param>
+      <key>port</key>
+      <value>1234</value>
+    </param>
+    <param>
+      <key>callback</key>
+      <value>set_ampl</value>
+    </param>
+    <param>
+      <key>variable</key>
+      <value>ampl</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(409, 35)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>xmlrpc_client</key>
+    <param>
+      <key>id</key>
+      <value>xmlrpc_client</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>addr</key>
+      <value>localhost</value>
+    </param>
+    <param>
+      <key>port</key>
+      <value>1234</value>
+    </param>
+    <param>
+      <key>callback</key>
+      <value>set_freq</value>
+    </param>
+    <param>
+      <key>variable</key>
+      <value>freq</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(222, 34)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>variable_slider</key>
+    <param>
+      <key>id</key>
+      <value>freq</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>label</key>
+      <value>Frequency (Hz)</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>1000</value>
+    </param>
+    <param>
+      <key>min</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>max</key>
+      <value>5000</value>
+    </param>
+    <param>
+      <key>num_steps</key>
+      <value>100</value>
+    </param>
+    <param>
+      <key>slider_type</key>
+      <value>horizontal</value>
+    </param>
+    <param>
+      <key>grid_pos</key>
+      <value>0, 0, 1, 2</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(207, 162)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>variable_slider</key>
+    <param>
+      <key>id</key>
+      <value>ampl</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>label</key>
+      <value>Amplitude</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>min</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>max</key>
+      <value>2</value>
+    </param>
+    <param>
+      <key>num_steps</key>
+      <value>100</value>
+    </param>
+    <param>
+      <key>slider_type</key>
+      <value>horizontal</value>
+    </param>
+    <param>
+      <key>grid_pos</key>
+      <value>1, 0, 1, 2</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(397, 167)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>variable_chooser</key>
+    <param>
+      <key>id</key>
+      <value>offset</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>label</key>
+      <value>Offset</value>
+    </param>
+    <param>
+      <key>value_index</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>choices</key>
+      <value>[-1, 0, 1]</value>
+    </param>
+    <param>
+      <key>labels</key>
+      <value>["neg", "zero", "pos"]</value>
+    </param>
+    <param>
+      <key>chooser_type</key>
+      <value>radio_buttons_horizontal</value>
+    </param>
+    <param>
+      <key>grid_pos</key>
+      <value>2, 0, 1, 2</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(596, 177)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>xmlrpc_client</key>
+    <param>
+      <key>id</key>
+      <value>xmlrpc_client1</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>addr</key>
+      <value>localhost</value>
+    </param>
+    <param>
+      <key>port</key>
+      <value>1234</value>
+    </param>
+    <param>
+      <key>callback</key>
+      <value>set_offset</value>
+    </param>
+    <param>
+      <key>variable</key>
+      <value>offset*ampl</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(608, 39)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>variable</key>
+    <param>
+      <key>id</key>
+      <value>samp_rate</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>32000</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(13, 172)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+</flow_graph>
\ No newline at end of file
diff --git a/grc/examples/xmlrpc/xmlrpc_client_script.py b/grc/examples/xmlrpc/xmlrpc_client_script.py
new file mode 100644
index 000000000..956fa07fb
--- /dev/null
+++ b/grc/examples/xmlrpc/xmlrpc_client_script.py
@@ -0,0 +1,23 @@
+#!/usr/bin/env python
+
+import time
+import random
+import xmlrpclib
+
+#create server object
+s = xmlrpclib.Server("http://localhost:1234")
+
+#randomly change parameters of the sinusoid
+for i in range(10):
+	#generate random values
+	new_freq = random.uniform(0, 5000)
+	new_ampl = random.uniform(0, 2)
+	new_offset = random.uniform(-1, 1)
+	#set new values 
+	time.sleep(1)
+	s.set_freq(new_freq)
+	time.sleep(1)
+	s.set_ampl(new_ampl)
+	time.sleep(1)
+	s.set_offset(new_offset)
+
diff --git a/grc/examples/xmlrpc/xmlrpc_server.grc b/grc/examples/xmlrpc/xmlrpc_server.grc
new file mode 100644
index 000000000..dc539ef1b
--- /dev/null
+++ b/grc/examples/xmlrpc/xmlrpc_server.grc
@@ -0,0 +1,384 @@
+<?xml version='1.0' encoding='ASCII'?>
+<flow_graph>
+  <timestamp>Thu Jul 24 14:27:42 2008</timestamp>
+  <block>
+    <key>options</key>
+    <param>
+      <key>id</key>
+      <value>server_block</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>title</key>
+      <value>XMLRPC Server</value>
+    </param>
+    <param>
+      <key>author</key>
+      <value>Example</value>
+    </param>
+    <param>
+      <key>description</key>
+      <value>example flow graph</value>
+    </param>
+    <param>
+      <key>window_size</key>
+      <value>1280, 1024</value>
+    </param>
+    <param>
+      <key>generate_options</key>
+      <value>wx_gui</value>
+    </param>
+    <param>
+      <key>category</key>
+      <value>Custom</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(10, 10)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gr_sig_source_x</key>
+    <param>
+      <key>id</key>
+      <value>gr_sig_source_x</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>float</value>
+    </param>
+    <param>
+      <key>samp_rate</key>
+      <value>samp_rate</value>
+    </param>
+    <param>
+      <key>waveform</key>
+      <value>gr.GR_COS_WAVE</value>
+    </param>
+    <param>
+      <key>freq</key>
+      <value>freq</value>
+    </param>
+    <param>
+      <key>amp</key>
+      <value>ampl</value>
+    </param>
+    <param>
+      <key>offset</key>
+      <value>offset</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(162, 200)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>variable</key>
+    <param>
+      <key>id</key>
+      <value>offset</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(12, 390)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>xmlrpc_server</key>
+    <param>
+      <key>id</key>
+      <value>xmlrpc_server</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>addr</key>
+      <value>localhost</value>
+    </param>
+    <param>
+      <key>port</key>
+      <value>1234</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(395, 240)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gr_throttle</key>
+    <param>
+      <key>id</key>
+      <value>gr_throttle</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>float</value>
+    </param>
+    <param>
+      <key>samples_per_second</key>
+      <value>samp_rate</value>
+    </param>
+    <param>
+      <key>vlen</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(386, 93)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>wxgui_scopesink2</key>
+    <param>
+      <key>id</key>
+      <value>wxgui_scopesink2</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>float</value>
+    </param>
+    <param>
+      <key>title</key>
+      <value>Scope Plot</value>
+    </param>
+    <param>
+      <key>samp_rate</key>
+      <value>samp_rate</value>
+    </param>
+    <param>
+      <key>frame_decim</key>
+      <value>15</value>
+    </param>
+    <param>
+      <key>v_scale</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>t_scale</key>
+      <value>.001</value>
+    </param>
+    <param>
+      <key>marker</key>
+      <value>set_format_line</value>
+    </param>
+    <param>
+      <key>num_inputs</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>grid_pos</key>
+      <value>0, 0, 2, 4</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(623, 28)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>wxgui_fftsink2</key>
+    <param>
+      <key>id</key>
+      <value>wxgui_fftsink2</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>float</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>8</value>
+    </param>
+    <param>
+      <key>ref_level</key>
+      <value>50</value>
+    </param>
+    <param>
+      <key>fft_size</key>
+      <value>512</value>
+    </param>
+    <param>
+      <key>fft_rate</key>
+      <value>15</value>
+    </param>
+    <param>
+      <key>avg_alpha</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>average</key>
+      <value>False</value>
+    </param>
+    <param>
+      <key>peak_hold</key>
+      <value>False</value>
+    </param>
+    <param>
+      <key>grid_pos</key>
+      <value>2, 0, 2, 4</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(630, 233)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>variable</key>
+    <param>
+      <key>id</key>
+      <value>samp_rate</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>32000</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(11, 160)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>variable</key>
+    <param>
+      <key>id</key>
+      <value>freq</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>1000</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(11, 237)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>variable</key>
+    <param>
+      <key>id</key>
+      <value>ampl</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(13, 315)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <connection>
+    <source_block_id>gr_sig_source_x</source_block_id>
+    <sink_block_id>gr_throttle</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_throttle</source_block_id>
+    <sink_block_id>wxgui_scopesink2</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_throttle</source_block_id>
+    <sink_block_id>wxgui_fftsink2</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+</flow_graph>
\ No newline at end of file