9 files changed, 1060 insertions, 0 deletions
diff --git a/gnuradio-examples/python/digital/limbo/README b/gnuradio-examples/python/digital/limbo/README
new file mode 100644
index 0000000000..fe48f43583
--- /dev/null
+++ b/gnuradio-examples/python/digital/limbo/README
@@ -0,0 +1,12 @@
+Files in here are in various states of disrepair and/or have been
+superceded by revised code in the directory above.
+
+They're here until we figure out what to do with them.
+
+
+* gmsk_test.py: stand-alone program that exercises the GMSK packet tx
+and rx code.  The two halves are connected with a simulated noisy
+channel.  It's easy to add extra instrumentation to log various internal 
+states.  We used a variant of this code to get this working in the
+first place. 
+
diff --git a/gnuradio-examples/python/digital/limbo/benchmark_gmsk_rx.py b/gnuradio-examples/python/digital/limbo/benchmark_gmsk_rx.py
new file mode 100755
index 0000000000..0e072d0f6a
--- /dev/null
+++ b/gnuradio-examples/python/digital/limbo/benchmark_gmsk_rx.py
@@ -0,0 +1,128 @@
+#!/usr/bin/env python
+#
+# Copyright 2005 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 2, 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.
+# 
+
+from gnuradio import gr, gru, blks
+from gnuradio import usrp
+from gnuradio import eng_notation
+from gnuradio.eng_option import eng_option
+from optparse import OptionParser
+
+import random
+import struct
+
+# from current dir
+from receive_path import receive_path
+import fusb_options
+
+#import os
+#print os.getpid()
+#raw_input('Attach and press enter')
+
+
+class my_graph(gr.flow_graph):
+
+    def __init__(self, demod_class, rx_subdev_spec,
+                 bitrate, decim_rate, spb,
+                 rx_callback, options, demod_kwargs):
+        gr.flow_graph.__init__(self)
+        self.rxpath = receive_path(self, demod_class, rx_subdev_spec,
+                                   bitrate, decim_rate, spb,
+                                   rx_callback, options, demod_kwargs)
+
+# /////////////////////////////////////////////////////////////////////////////
+#                                   main
+# /////////////////////////////////////////////////////////////////////////////
+
+global n_rcvd, n_right
+
+def main():
+    global n_rcvd, n_right
+
+    n_rcvd = 0
+    n_right = 0
+    
+    def rx_callback(ok, payload):
+        global n_rcvd, n_right
+        (pktno,) = struct.unpack('!H', payload[0:2])
+        n_rcvd += 1
+        if ok:
+            n_right += 1
+
+        print "ok = %r  pktno = %4d  n_rcvd = %4d  n_right = %4d" % (
+            ok, pktno, n_rcvd, n_right)
+
+    parser = OptionParser (option_class=eng_option)
+    parser.add_option("-R", "--rx-subdev-spec", type="subdev", default=None,
+                      help="select USRP Rx side A or B")
+    parser.add_option("-f", "--freq", type="eng_float", default=423.1e6,
+                      help="set Rx frequency to FREQ [default=%default]",
+                      metavar="FREQ")
+    parser.add_option("-r", "--bitrate", type="eng_float", default=None,
+                      help="specify bitrate.  spb and interp will be derived.")
+    parser.add_option("-g", "--rx-gain", type="eng_float", default=27,
+                      help="set rx gain")
+    parser.add_option("-S", "--spb", type="int", default=None,
+                      help="set samples/baud [default=%default]")
+    parser.add_option("-d", "--decim", type="intx", default=None,
+                      help="set fpga decim rate to DECIM [default=%default]")
+    fusb_options.add_options(parser)
+    (options, args) = parser.parse_args ()
+
+    if len(args) != 0:
+        parser.print_help()
+        sys.exit(1)
+
+    if options.freq < 1e6:
+        options.freq *= 1e6
+
+    demod_kwargs = { } # placeholder    
+    
+    # build the graph
+    fg = my_graph(blks.gmsk_demod,
+                  options.rx_subdev_spec, options.bitrate,
+                  options.decim, options.spb, rx_callback,
+                  options, demod_kwargs)
+
+    print "bitrate: %sb/sec" % (eng_notation.num_to_str(fg.rxpath.bitrate()),)
+    print "spb:     %3d" % (fg.rxpath.spb(),)
+    print "decim:   %3d" % (fg.rxpath.decim(),)
+
+    ok = fg.rxpath.set_freq(options.freq)
+    if not ok:
+        print "Failed to set Rx frequency to %s" % (eng_notation.num_to_str(options.freq),)
+        raise SystemExit
+    
+    fg.rxpath.set_gain(options.rx_gain)
+    print "Rx gain_range: ", fg.rxpath.subdev.gain_range(), " using", fg.rxpath.gain
+
+    r = gr.enable_realtime_scheduling()
+    if r != gr.RT_OK:
+        print "Warning: Failed to enable realtime scheduling."
+
+    fg.start()        # start flow graph
+    fg.wait()         # wait for it to finish
+
+if __name__ == '__main__':
+    try:
+        main()
+    except KeyboardInterrupt:
+        pass
diff --git a/gnuradio-examples/python/digital/limbo/benchmark_gmsk_tx.py b/gnuradio-examples/python/digital/limbo/benchmark_gmsk_tx.py
new file mode 100755
index 0000000000..ec78d24b93
--- /dev/null
+++ b/gnuradio-examples/python/digital/limbo/benchmark_gmsk_tx.py
@@ -0,0 +1,150 @@
+#!/usr/bin/env python
+#
+# Copyright 2005,2006 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 2, 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.
+# 
+
+from gnuradio import gr, gru, blks
+from gnuradio import usrp
+from gnuradio import eng_notation
+from gnuradio.eng_option import eng_option
+from optparse import OptionParser
+
+import random
+import time
+import struct
+import sys
+
+# from current dir
+from transmit_path import transmit_path
+import fusb_options
+
+#import os
+#print os.getpid()
+#raw_input('Attach and press enter')
+
+class my_graph(gr.flow_graph):
+
+    def __init__(self, options, mod_kwargs):
+        gr.flow_graph.__init__(self)
+        self.txpath = transmit_path(self, options, mod_kwargs)
+
+
+# /////////////////////////////////////////////////////////////////////////////
+#                                   main
+# /////////////////////////////////////////////////////////////////////////////
+
+def main():
+
+    def send_pkt(payload='', eof=False):
+        return fg.txpath.send_pkt(payload, eof)
+
+    def rx_callback(ok, payload):
+        print "ok = %r, payload = '%s'" % (ok, payload)
+
+    parser = OptionParser (option_class=eng_option)
+    parser.add_option("-T", "--tx-subdev-spec", type="subdev", default=None,
+                      help="select USRP Tx side A or B")
+    parser.add_option("-f", "--freq", type="eng_float", default=423.1e6,
+                      help="set Tx and Rx frequency to FREQ [default=%default]",
+                      metavar="FREQ")
+    parser.add_option("-r", "--bitrate", type="eng_float", default=None,
+                      help="specify bitrate.  spb and interp will be derived.")
+    parser.add_option("-S", "--spb", type="int", default=2,
+                      help="set samples/baud [default=%default]")
+    parser.add_option("-i", "--interp", type="intx", default=None,
+                      help="set fpga interpolation rate to INTERP [default=%default]")
+    parser.add_option("-s", "--size", type="eng_float", default=1500,
+                      help="set packet size [default=%default]")
+    parser.add_option("", "--bt", type="float", default=0.3,
+                      help="set bandwidth-time product [default=%default]")
+    parser.add_option("-g", "--gain", type="eng_float", default=100.0,
+                      help="transmitter gain [default=%default]")
+    parser.add_option("-M", "--megabytes", type="eng_float", default=1.0,
+                      help="set megabytes to transmit [default=%default]")
+    parser.add_option("","--discontinuous", action="store_true", default=False,
+                      help="enable discontinous transmission (bursts of 5 packets)")
+    fusb_options.add_options(parser)
+    (options, args) = parser.parse_args ()
+
+    if len(args) != 0:
+        parser.print_help()
+        sys.exit(1)
+
+    if options.freq < 1e6:
+        options.freq *= 1e6
+
+    pkt_size = int(options.size)
+
+    # Add gmsk_mod modulator class to options list
+    options.modulation = getattr(blks, "gmsk_mod")
+
+    # Add GMSK modulator's properties
+    mod_kwargs = {
+        'spb': options.spb,
+        'bt' : options.bt,
+        'verbose' : False,
+        'debug'   : False,
+        }
+        
+    # build the graph
+    fg = my_graph(options, mod_kwargs)
+
+    print "bitrate: %sbps" % (eng_notation.num_to_str(fg.txpath.bitrate()),)
+    print "spb:     %3d" % (fg.txpath.spb(),)
+    print "interp:  %3d" % (fg.txpath.interp(),)
+
+    ok = fg.txpath.set_freq(options.freq)
+    if not ok:
+        print "Failed to set Tx frequency to %s" % (eng_notation.num_to_str(options.freq),)
+        raise SystemExit
+    else:
+        print "Transmitting on frequency %s" % (eng_notation.num_to_str(options.freq))
+
+    r = gr.enable_realtime_scheduling()
+    if r != gr.RT_OK:
+        print "Warning: failed to enable realtime scheduling"
+    else:
+        print "Started realtime scheduling"
+
+    fg.start()                       # start flow graph
+
+    # generate and send packets
+    nbytes = int(1e6 * options.megabytes)
+    n = 0
+    pktno = 0
+
+    while n < nbytes:
+        send_pkt(struct.pack('!H', pktno) + (pkt_size - 2) * chr(pktno & 0xff))
+        n += pkt_size
+        sys.stderr.write('.')
+        if options.discontinuous and pktno % 5 == 4:
+            time.sleep(1)
+        pktno += 1
+        
+    send_pkt(eof=True)
+    fg.wait()                       # wait for it to finish
+    fg.txpath.set_auto_tr(False)
+
+
+if __name__ == '__main__':
+    try:
+        main()
+    except KeyboardInterrupt:
+        pass
diff --git a/gnuradio-examples/python/digital/limbo/benchmark_mpsk_rx.py b/gnuradio-examples/python/digital/limbo/benchmark_mpsk_rx.py
new file mode 100755
index 0000000000..9bb70106f6
--- /dev/null
+++ b/gnuradio-examples/python/digital/limbo/benchmark_mpsk_rx.py
@@ -0,0 +1,149 @@
+#!/usr/bin/env python
+#
+# Copyright 2006 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 2, 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.
+# 
+
+from gnuradio import gr, gru, blks
+from gnuradio import usrp
+from gnuradio import eng_notation
+from gnuradio.eng_option import eng_option
+from optparse import OptionParser
+
+import random
+import struct
+
+# from current dir
+from bpsk import bpsk_demod
+from dbpsk import dbpsk_demod
+from dqpsk import dqpsk_demod
+from receive_path import receive_path
+import fusb_options
+
+if 1:
+    import os
+    print os.getpid()
+    raw_input('Attach and press enter')
+
+
+class my_graph(gr.flow_graph):
+
+    def __init__(self, demod_class, rx_subdev_spec,
+                 bitrate, decim_rate, spb,
+                 rx_callback, options, demod_kwargs):
+        gr.flow_graph.__init__(self)
+        self.rxpath = receive_path(self, demod_class, rx_subdev_spec,
+                                   bitrate, decim_rate, spb,
+                                   rx_callback, options, demod_kwargs)
+
+# /////////////////////////////////////////////////////////////////////////////
+#                                   main
+# /////////////////////////////////////////////////////////////////////////////
+
+global n_rcvd, n_right
+
+def main():
+    global n_rcvd, n_right
+
+    n_rcvd = 0
+    n_right = 0
+    
+    def rx_callback(ok, payload):
+        global n_rcvd, n_right
+        (pktno,) = struct.unpack('!H', payload[0:2])
+        n_rcvd += 1
+        if ok:
+            n_right += 1
+
+        print "ok = %r  pktno = %4d  n_rcvd = %4d  n_right = %4d" % (
+            ok, pktno, n_rcvd, n_right)
+
+    parser = OptionParser (option_class=eng_option)
+    parser.add_option("-R", "--rx-subdev-spec", type="subdev", default=None,
+                      help="select USRP Rx side A or B")
+    parser.add_option("-f", "--freq", type="eng_float", default=423.1e6,
+                      help="set Rx frequency to FREQ [default=%default]",
+                      metavar="FREQ")
+    parser.add_option("-r", "--bitrate", type="eng_float", default=None,
+                      help="specify bitrate.  spb and interp will be derived.")
+    parser.add_option("-S", "--spb", type="int", default=None,
+                      help="set samples/baud [default=%default]")
+    parser.add_option("-d", "--decim", type="intx", default=None,
+                      help="set fpga decim rate to DECIM [default=%default]")
+    parser.add_option("-m", "--modulation", type="string", default='dbpsk',
+                      help="modulation type (bpsk, dbpsk, dqpsk) [default=%default]")
+    parser.add_option("", "--excess-bw", type="float", default=0.3,
+                      help="set RRC excess bandwith factor [default=%default]")
+    parser.add_option("-g", "--gain", type="eng_float", default=27,
+                      help="set rx gain")
+    parser.add_option("","--log", action="store_true", default=False,
+                      help="enable diagnostic logging")
+    fusb_options.add_options(parser)
+    (options, args) = parser.parse_args ()
+
+    if len(args) != 0:
+        parser.print_help()
+        sys.exit(1)
+
+    if options.freq < 1e6:
+        options.freq *= 1e6
+
+    demod_kwargs = {
+            'excess_bw' : options.excess_bw,
+            }
+
+    #FIXME: Needs to be worked in to overall structure; this will be fixed
+    #       once static class definitions for modulations are defined
+    if(options.modulation=='bpsk'):
+        modulation=bpsk_demod
+    elif(options.modulation=='dbpsk'):
+        modulation=dbpsk_demod
+    else:
+        modulation=dqpsk_demod
+
+    # build the graph
+    fg = my_graph(modulation,
+                  options.rx_subdev_spec, options.bitrate,
+                  options.decim, options.spb,
+                  rx_callback, options, demod_kwargs)
+
+    print "bitrate: %sb/sec" % (eng_notation.num_to_str(fg.rxpath.bitrate()),)
+    print "spb:     %3d" % (fg.rxpath.spb(),)
+    print "decim:   %3d" % (fg.rxpath.decim(),)
+
+    ok = fg.rxpath.set_freq(options.freq)
+    if not ok:
+        print "Failed to set Rx frequency to %s" % (eng_notation.num_to_str(options.freq),)
+        raise SystemExit
+    
+    fg.rxpath.set_gain(options.gain)
+    print "Rx gain_range: ", fg.rxpath.subdev.gain_range(), " using", fg.rxpath.gain
+
+    r = gr.enable_realtime_scheduling()
+    if r != gr.RT_OK:
+        print "Warning: Failed to enable realtime scheduling."
+
+    fg.start()        # start flow graph
+    fg.wait()         # wait for it to finish
+
+if __name__ == '__main__':
+    try:
+        main()
+    except KeyboardInterrupt:
+        pass
diff --git a/gnuradio-examples/python/digital/limbo/benchmark_mpsk_tx.py b/gnuradio-examples/python/digital/limbo/benchmark_mpsk_tx.py
new file mode 100755
index 0000000000..ec08fb6807
--- /dev/null
+++ b/gnuradio-examples/python/digital/limbo/benchmark_mpsk_tx.py
@@ -0,0 +1,151 @@
+#!/usr/bin/env python
+#
+# Copyright 2005, 2006 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 2, 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.
+# 
+
+from gnuradio import gr, gru, blks
+from gnuradio import usrp
+from gnuradio import eng_notation
+from gnuradio.eng_option import eng_option
+from optparse import OptionParser
+
+import random, time, struct, sys
+
+# from current dir
+from transmit_path import transmit_path
+import fusb_options
+
+#import os
+#print os.getpid()
+#raw_input('Attach and press enter')
+
+
+class my_graph(gr.flow_graph):
+
+    def __init__(self, options, mod_kwargs):
+        gr.flow_graph.__init__(self)
+        self.txpath = transmit_path(self, options, mod_kwargs)
+
+
+# /////////////////////////////////////////////////////////////////////////////
+#                                   main
+# /////////////////////////////////////////////////////////////////////////////
+
+def main():
+
+    def send_pkt(payload='', eof=False):
+        return fg.txpath.send_pkt(payload, eof)
+
+    def rx_callback(ok, payload):
+        print "ok = %r, payload = '%s'" % (ok, payload)
+
+    parser = OptionParser (option_class=eng_option)
+    parser.add_option("-T", "--tx-subdev-spec", type="subdev", default=None,
+                      help="select USRP Tx side A or B")
+    parser.add_option("-f", "--freq", type="eng_float", default=423.1e6,
+                      help="set Tx and Rx frequency to FREQ [default=%default]",
+                      metavar="FREQ")
+    parser.add_option("-r", "--bitrate", type="eng_float", default=None,
+                      help="specify bitrate.  spb and interp will be derived.")
+    parser.add_option("-S", "--spb", type="int", default=2,
+                      help="set samples/baud [default=%default]")
+    parser.add_option("-i", "--interp", type="intx", default=None,
+                      help="set fpga interpolation rate to INTERP [default=%default]")
+    parser.add_option("-s", "--size", type="eng_float", default=1500,
+                      help="set packet size [default=%default]")
+    parser.add_option("-g", "--gain", type="eng_float", default=100.0,
+                      help="transmitter gain [default=%default]")
+    parser.add_option("-M", "--megabytes", type="eng_float", default=1.0,
+                      help="set megabytes to transmit [default=%default]")
+    parser.add_option("","--discontinuous", action="store_true", default=False,
+                      help="enable discontinous transmission (bursts of 5 packets)")
+
+    parser.add_option("-m", "--modulation", type="string", default='dbpsk',
+                      help="modulation type (bpsk, dbpsk, dqpsk) [default=%default]")
+    parser.add_option("", "--excess-bw", type="float", default=0.3,
+                      help="set RRC excess bandwith factor [default=%default]")
+    parser.add_option("", "--no-gray-code", action="store_false", default=True,
+                      help="Don't use gray coding on modulated bits [default=%default]")
+
+    fusb_options.add_options(parser)
+    (options, args) = parser.parse_args ()
+
+    if len(args) != 0:
+        parser.print_help()
+        sys.exit(1)
+
+    if options.freq < 1e6:
+        options.freq *= 1e6
+
+    pkt_size = int(options.size)
+
+    # Add PSK modulator class to options list
+    options.modulation = getattr(blks, options.modulation + "_mod")
+ 
+    # Add PSK modulator's properties
+    mod_kwargs = {
+        'spb'       : options.spb,
+        'excess_bw' : options.excess_bw,
+        'gray_code' : options.no_gray_code,
+        'verbose'   : False,
+        'debug'     : False,
+        }
+ 
+    # build the graph
+    fg = my_graph(options, mod_kwargs)
+
+    print "bitrate: %sb/sec" % (eng_notation.num_to_str(fg.txpath.bitrate()),)
+    print "spb:     %3d" % (fg.txpath.spb(),)
+    print "interp:  %3d" % (fg.txpath.interp(),)
+
+    ok = fg.txpath.set_freq(options.freq)
+    if not ok:
+        print "Failed to set Tx frequency to %s" % (eng_notation.num_to_str(options.freq),)
+        raise SystemExit
+
+    r = gr.enable_realtime_scheduling()
+    if r != gr.RT_OK:
+        print "Warning: failed to enable realtime scheduling"
+
+    fg.start()                       # start flow graph
+
+    # generate and send packets
+    nbytes = int(1e6 * options.megabytes)
+    n = 0
+    pktno = 0
+
+    while n < nbytes:
+        send_pkt(struct.pack('!H', pktno) + (pkt_size - 2) * chr(pktno & 0xff))
+        n += pkt_size
+        sys.stderr.write('.')
+        if options.discontinuous and pktno % 5 == 4:
+            time.sleep(1)
+        pktno += 1
+        
+    send_pkt(eof=True)
+    fg.wait()                       # wait for it to finish
+    fg.txpath.set_auto_tr(False)
+
+
+if __name__ == '__main__':
+    try:
+        main()
+    except KeyboardInterrupt:
+        pass
diff --git a/gnuradio-examples/python/digital/limbo/gmsk_test.py b/gnuradio-examples/python/digital/limbo/gmsk_test.py
new file mode 100755
index 0000000000..7ae69a0a94
--- /dev/null
+++ b/gnuradio-examples/python/digital/limbo/gmsk_test.py
@@ -0,0 +1,115 @@
+#!/usr/bin/env python
+
+from gnuradio import gr, blks
+from gnuradio.eng_option import eng_option
+from optparse import OptionParser
+import random
+import struct
+
+#import os
+#print os.getpid()
+#raw_input('Attach and press enter')
+
+
+class my_graph(gr.flow_graph):
+
+    def __init__(self, rx_callback, spb, bt, SNR, freq_error):
+        gr.flow_graph.__init__(self)
+
+        fg = self
+
+        # Tuning Parameters
+        gain_mu = 0.002*spb
+        omega = spb*(1+freq_error)
+
+        # transmitter
+        self.packet_transmitter = blks.gmsk2_mod_pkts(fg, spb=spb, bt=bt)
+
+        # add some noise
+        add = gr.add_cc()
+        noise = gr.noise_source_c(gr.GR_GAUSSIAN, pow(10.0,-SNR/20.0))
+
+        # channel filter
+        rx_filt_taps = gr.firdes.low_pass(1,spb,0.8,0.1,gr.firdes.WIN_HANN)
+        rx_filt = gr.fir_filter_ccf(1,rx_filt_taps)
+
+        # receiver
+        self.packet_receiver = blks.gmsk2_demod_pkts(fg, callback=rx_callback,
+                                                     spb=spb, gain_mu=gain_mu,
+                                                     freq_error=freq_error, omega=omega)
+
+        fg.connect (self.packet_transmitter, (add,0))
+        fg.connect (noise, (add,1))
+        fg.connect(add, rx_filt, self.packet_receiver)
+
+
+class stats(object):
+    def __init__(self):
+        self.npkts = 0
+        self.nright = 0
+        
+def main():
+    st = stats()
+    
+    def send_pkt(payload='', eof=False):
+        fg.packet_transmitter.send_pkt(payload, eof)
+
+    def rx_callback(ok, payload):
+        st.npkts += 1
+        if ok:
+            st.nright += 1
+        if len(payload) <= 16:
+            print "ok = %5r  payload = '%s'  %d/%d" % (ok, payload, st.nright, st.npkts)
+        else:
+            (pktno,) = struct.unpack('!H', payload[0:2])
+            print "ok = %5r  pktno = %4d  len(payload) = %4d  %d/%d" % (ok, pktno, len(payload),
+                                                                        st.nright, st.npkts)
+
+
+    parser = OptionParser (option_class=eng_option)
+    parser.add_option("-M", "--megabytes", type="eng_float", default=1,
+                      help="set megabytes to transmit [default=%default]")
+    parser.add_option("-s", "--size", type="eng_float", default=1500,
+                      help="set packet size [default=%default]")
+    parser.add_option("","--spb", type=int, default=4,
+                      help="set samples per baud to SPB [default=%default]")
+    parser.add_option("", "--bt", type="eng_float", default=0.3,
+                      help="set bandwidth time product for Gaussian filter [default=%default]")
+    parser.add_option("", "--snr", type="eng_float", default=20,
+                      help="set SNR in dB for simulation [default=%default]")
+    parser.add_option("", "--freq-error", type="eng_float", default=0,
+                      help="set frequency error for simulation [default=%default]")
+    (options, args) = parser.parse_args ()
+
+    if len(args) != 0:
+        parser.print_help()
+        sys.exit(1)
+
+    pkt_size = int(options.size)
+
+    fg = my_graph(rx_callback, options.spb, options.bt, options.snr, options.freq_error)
+    fg.start()
+
+    nbytes = int(1e6 * options.megabytes)
+    n = 0
+    pktno = 0
+
+    send_pkt('Hello World')
+
+    # generate and send packets
+    while n < nbytes:
+        send_pkt(struct.pack('!H', pktno) + (pkt_size - 2) * chr(pktno & 0xff))
+        n += pkt_size
+        pktno += 1
+
+    send_pkt('Goodbye World')
+    send_pkt(eof=True)             # tell modulator we're not sending any more pkts
+
+    fg.wait()
+
+
+if __name__ == '__main__':
+    try:
+        main()
+    except KeyboardInterrupt:
+        pass
diff --git a/gnuradio-examples/python/digital/limbo/mpsk_test.py b/gnuradio-examples/python/digital/limbo/mpsk_test.py
new file mode 100755
index 0000000000..1f257d9c5d
--- /dev/null
+++ b/gnuradio-examples/python/digital/limbo/mpsk_test.py
@@ -0,0 +1,125 @@
+#!/usr/bin/env python
+
+from gnuradio import gr, blks
+from gnuradio.eng_option import eng_option
+from optparse import OptionParser
+import random
+import struct
+from mpsk_pkt import *
+import cmath
+
+class my_graph(gr.flow_graph):
+
+    def __init__(self, rx_callback, spb, excess_bw, SNR, freq_error, arity):
+        gr.flow_graph.__init__(self)
+
+        fg = self
+
+        # Tuning Parameters
+        gain_mu = 0.05/spb
+
+        # transmitter
+        self.packet_transmitter = \
+          mpsk_mod_pkts(fg, spb=spb, excess_bw=excess_bw, diff=True, arity=arity)
+
+        # ----------------------------------------------------------------
+        #                       Channel model
+        # ----------------------------------------------------------------
+
+        awgn = gr.noise_source_c(gr.GR_GAUSSIAN, pow(10.0,-SNR/20.0))
+        add = gr.add_cc()            # add some noise
+        fg.connect(awgn, (add,1))
+        radians = 17*pi/180
+        phase_rotate = gr.multiply_const_cc(cmath.exp(radians * 1j))
+
+        # ----------------------------------------------------------------
+
+        # channel filter
+        rx_filt_taps = gr.firdes.low_pass(1,spb,0.8,0.1,gr.firdes.WIN_HANN)
+        #rx_filt_taps = (1,)
+        rx_filt = gr.fir_filter_ccf(1,rx_filt_taps)
+
+        # receiver
+        self.packet_receiver = \
+            mpsk_demod_pkts(fg, callback=rx_callback,
+                            excess_bw=excess_bw, arity=arity, diff=True,
+                            costas_alpha=.005, gain_mu=gain_mu, spb=spb)
+        
+        fg.connect (self.packet_transmitter, (add,0))
+        fg.connect(add, phase_rotate, rx_filt, self.packet_receiver)
+
+
+class stats(object):
+    def __init__(self):
+        self.npkts = 0
+        self.nright = 0
+        
+def main():
+    st = stats()
+    
+    def send_pkt(payload='', eof=False):
+        fg.packet_transmitter.send_pkt(payload, eof)
+
+    def rx_callback(ok, payload):
+        st.npkts += 1
+        if ok:
+            st.nright += 1
+        if len(payload) <= 16:
+            print "ok = %5r  payload = '%s'  %d/%d" % (ok, payload, st.nright, st.npkts)
+        else:
+            (pktno,) = struct.unpack('!H', payload[0:2])
+            print "ok = %5r  pktno = %4d  len(payload) = %4d  %d/%d" % (ok, pktno, len(payload),
+                                                                        st.nright, st.npkts)
+
+
+    parser = OptionParser (option_class=eng_option)
+    parser.add_option("-M", "--megabytes", type="eng_float", default=1,
+                      help="set megabytes to transmit [default=%default]")
+    parser.add_option("-s", "--size", type="eng_float", default=1500,
+                      help="set packet size [default=%default]")
+    parser.add_option("","--spb", type=int, default=4,
+                      help="set samples per baud to SPB [default=%default]")
+    parser.add_option("", "--excess-bw", type="eng_float", default=0.4,
+                      help="set excess bandwidth for RRC filter [default=%default]")
+    parser.add_option("", "--snr", type="eng_float", default=40,
+                      help="set SNR in dB for simulation [default=%default]")
+    parser.add_option("", "--m-arity", type=int, default=4,
+                      help="PSK arity [default=%default]")
+    parser.add_option("", "--freq-error", type="eng_float", default=0,
+                      help="set frequency error for simulation [default=%default]")
+
+    (options, args) = parser.parse_args ()
+
+    if len(args) != 0:
+        parser.print_help()
+        sys.exit(1)
+
+    pkt_size = int(options.size)
+
+    fg = my_graph(rx_callback, options.spb, options.excess_bw, options.snr,
+                  options.freq_error, options.m_arity)
+    fg.start()
+
+    nbytes = int(1e6 * options.megabytes)
+    n = 0
+    pktno = 0
+
+    send_pkt('Hello World')
+
+    # generate and send packets
+    while n < nbytes:
+        send_pkt(struct.pack('!H', pktno) + (pkt_size - 2) * chr(pktno & 0xff))
+        n += pkt_size
+        pktno += 1
+
+    send_pkt('Goodbye World')
+    send_pkt(eof=True)             # tell modulator we're not sending any more pkts
+
+    fg.wait()
+
+
+if __name__ == '__main__':
+    try:
+        main()
+    except KeyboardInterrupt:
+        pass
diff --git a/gnuradio-examples/python/digital/limbo/qpsk_tester.py b/gnuradio-examples/python/digital/limbo/qpsk_tester.py
new file mode 100644
index 0000000000..ea7bae2ebc
--- /dev/null
+++ b/gnuradio-examples/python/digital/limbo/qpsk_tester.py
@@ -0,0 +1,127 @@
+#!/usr/bin/env python
+
+import random
+from gnuradio import gr
+
+default_access_code = '\xAC\xDD\xA4\xE2\xF2\x8C\x20\xFC'
+
+def string_to_1_0_list(s):
+    r = []
+    for ch in s:
+        x = ord(ch)
+        for i in range(8):
+            t = (x >> i) & 0x1
+            r.append(t)
+
+    return r
+
+def to_1_0_string(L):
+    return ''.join(map(lambda x: chr(x + ord('0')), L))
+
+code = string_to_1_0_list(default_access_code)
+access_code = to_1_0_string(code)
+
+use_agc        = 0
+use_rrc_tx     = 1
+use_rrc_rx     = 1
+use_sync_loop  = 1
+use_clock_sync = 1
+
+def main():
+    fg = gr.flow_graph()
+
+#    data = (1,2,3,4,5,6,7,8,9)
+    random.seed()
+    data = [random.randint(1,100) for i in range(20000)]
+    data[0] = 0 # you know, for the diff encoding stuff
+    bytes_src = gr.vector_source_b(data,False)
+
+    k = 2
+    spb = 50
+    ntaps = 11*spb
+    excess_bw = 0.9
+    threshold = 12
+    constellation  = (1+0j, 0+1j, -1+0j, 0-1j)
+    
+    bytes2chunks   = gr.packed_to_unpacked_bb(k, gr.GR_MSB_FIRST)
+    diffenc        = gr.diff_encoder_bb(4)
+    chunks2symbols = gr.chunks_to_symbols_bc(constellation)
+
+    if use_rrc_tx:
+        rrc_taps_tx = gr.firdes.root_raised_cosine(spb, spb, 1.0, \
+                                                   excess_bw, ntaps)
+        rrc_tx = gr.interp_fir_filter_ccf(spb, rrc_taps_tx)
+    else:
+        rrc_tx = gr.interp_fir_filter_ccf(1, (1,))
+
+################### CHANNEL MODEL #############################
+
+    phase_rotate = gr.multiply_const_cc(1-0.36j)
+    channel      = gr.add_cc()
+    awgn         = gr.noise_source_c(gr.GR_GAUSSIAN, 0.5)
+    fg.connect(awgn, (channel,1))
+    
+################### CHANNEL MODEL #############################
+
+    if use_agc:
+        agc = gr.agc_cc(1e-4, 1, 1)
+    else:
+        agc = gr.multiply_const_cc(1)
+
+    # Downconverter
+    if use_sync_loop:
+        costas_alpha=0.005
+        beta = costas_alpha*costas_alpha*0.25
+        sync_loop = gr.costas_loop_cc(costas_alpha, beta, 0.05, -0.05, 0)
+    else:
+        sync_loop = gr.multiply_const_cc(1)
+
+    if use_rrc_rx:
+        rrc_taps_rx = gr.firdes.root_raised_cosine(1, spb, 1.0, \
+                                                   excess_bw, ntaps)
+        rrc_rx = gr.fir_filter_ccf(1, rrc_taps_rx)
+    else:
+        rrc_rx = gr.fir_filter_ccf(1, (1,))
+   
+    # Sampler
+    if use_clock_sync:
+        mu = 0.05
+        omega = spb
+        gain_mu = 0.05
+        gain_omega = 0.25*gain_mu*gain_mu
+        omega_rel_limit = 0.5
+        clock_sync = gr.clock_recovery_mm_cc(omega, gain_omega, mu, \
+                                             gain_mu, omega_rel_limit)
+        #clock_sync.set_verbose(True);
+    else:
+        clock_sync = gr.fir_filter_ccf(1, (1,))
+
+    diff_phasor = gr.diff_phasor_cc()
+    slicer = gr.constellation_decoder_cb((constellation), (0,1,2,3))
+    unpack = gr.unpack_k_bits_bb(k)
+    access = gr.correlate_access_code_bb(access_code,threshold)
+
+    sink = gr.file_sink(gr.sizeof_char, 'output.dat')
+
+    fg.connect(bytes_src, bytes2chunks, diffenc, chunks2symbols, rrc_tx)
+    fg.connect(rrc_tx, phase_rotate, channel, agc)
+    fg.connect(agc, sync_loop, rrc_rx, clock_sync, diff_phasor, slicer, sink)
+ 
+    test = gr.file_sink(gr.sizeof_gr_complex, 'test.dat')
+    fg.connect(rrc_rx, test)
+
+    fg.connect(chunks2symbols, gr.file_sink(gr.sizeof_gr_complex, 'rrc_tx.dat'))  # into TX RRC
+    fg.connect(channel, gr.file_sink(gr.sizeof_gr_complex, 'channel.dat'))        # Out of TX RRC
+    fg.connect(rrc_rx, gr.file_sink(gr.sizeof_gr_complex, 'rrc_rx.dat'))          # Out of RX RRC -> clock_sync
+    fg.connect(clock_sync, gr.file_sink(gr.sizeof_gr_complex, 'clock_sync.dat'))  # Out of M&M sync loop
+    fg.connect(bytes2chunks, gr.file_sink(gr.sizeof_char, 'source.dat'))
+
+    fg.start()
+    fg.wait()
+
+if __name__ == "__main__":
+    main()
+        
+    
+
+ 
diff --git a/gnuradio-examples/python/digital/limbo/qpsk_usrp_tester.py b/gnuradio-examples/python/digital/limbo/qpsk_usrp_tester.py
new file mode 100644
index 0000000000..bf7698a2b2
--- /dev/null
+++ b/gnuradio-examples/python/digital/limbo/qpsk_usrp_tester.py
@@ -0,0 +1,103 @@
+#!/usr/bin/env python
+
+import random
+from gnuradio import gr, gru, usrp
+
+default_access_code = '\xAC\xDD\xA4\xE2\xF2\x8C\x20\xFC'
+
+def string_to_1_0_list(s):
+    r = []
+    for ch in s:
+        x = ord(ch)
+        for i in range(8):
+            t = (x >> i) & 0x1
+            r.append(t)
+
+    return r
+
+def to_1_0_string(L):
+    return ''.join(map(lambda x: chr(x + ord('0')), L))
+
+code = string_to_1_0_list(default_access_code)
+
+access_code = to_1_0_string(code)
+
+def main():
+
+    fg = gr.flow_graph()
+    f_rf = 5e6
+    fs = 400e3
+    sr = 100e3
+    alpha = 0.5
+    M = 4
+    k = int(gru.log2(M))
+    
+    # Source
+    src = usrp.source_c ()
+    adc_rate = src.adc_rate()
+    usrp_decim = int(adc_rate / fs)
+    src.set_decim_rate(usrp_decim)
+        
+    subdev_spec = usrp.pick_rx_subdevice(src)
+    subdev = usrp.selected_subdev(src, subdev_spec)
+    print "Using RX d'board %s" % (subdev.side_and_name(),)
+    src.set_mux(usrp.determine_rx_mux_value(src, subdev_spec))
+    src.tune(0, subdev, f_rf)
+        
+    g = subdev.gain_range()
+    subdev.set_gain(g[1])
+    subdev.set_auto_tr(True)
+        
+    print "USRP Decimation Rate = %d" % usrp_decim
+    print "RF Frequency = %d" % f_rf
+
+    agc = gr.multiply_const_cc(0.0025)
+        
+    # Downconverter
+    costas_alpha=0.005
+    beta = costas_alpha*costas_alpha*0.25
+    sync_loop = gr.costas_loop_cc(costas_alpha, beta, 0.05, -0.05, 0)
+
+    # Stage 2
+#    fs2 = 200e3
+#    D = int(fs / fs2)
+#    decimator = gr.keep_one_in_n(gr.sizeof_gr_complex, D)
+#    print "D = %d\nAfter decimator fs = %f" % (D, fs2)
+
+    # Demodulator
+    taps = gr.firdes.root_raised_cosine(1, fs, sr, alpha, 45)
+    rrc  = gr.fir_filter_ccf(1, taps)
+    
+    # Sampler
+    mu = 0.01
+    omega = 4.3
+    gain_mu = 0.05
+    gain_omega = 0.25*gain_mu*gain_mu
+    omega_rel_limit = 0.5
+    clock_sync = gr.clock_recovery_mm_cc(omega, gain_omega, mu,
+                                         gain_mu, omega_rel_limit)
+    clock_sync.set_verbose(False)
+
+    diff_phasor = gr.diff_phasor_cc()
+
+    threshold = 12
+    constellation = (1+0j, 0+1j, -1+0j, 0-1j)
+    slicer = gr.constellation_decoder_cb((constellation), (0,1,2,3))
+    unpack = gr.unpack_k_bits_bb(k)
+    access = gr.correlate_access_code_bb(access_code,threshold)
+
+    test = gr.file_sink(gr.sizeof_gr_complex, 'test.dat')
+    sink = gr.file_sink(gr.sizeof_char, 'output.dat')
+
+    fg.connect(src, agc, sync_loop, rrc, clock_sync)
+    fg.connect(clock_sync, diff_phasor, slicer, unpack, access, sink)
+
+    fg.connect(slicer, gr.file_sink(gr.sizeof_char, 'chunks.dat'))
+    fg.connect(unpack, gr.file_sink(gr.sizeof_char, 'unpack.dat'))
+    fg.connect(clock_sync, gr.file_sink(gr.sizeof_gr_complex, 'phasor.dat'))
+
+    fg.start()
+    fg.wait()
+
+if __name__ == "__main__":
+    main()