digital: reverting back to ofdm, pkt, and modulation_utils in gnuradio-core to master. Moved new versions under gr-digital.

3 files changed, 580 insertions, 0 deletions

diff --git a/gr-digital/python/modulation_utils2.py b/gr-digital/python/modulation_utils2.py
new file mode 100644
index 000000000..f30055f4a
--- /dev/null
+++ b/gr-digital/python/modulation_utils2.py
@@ -0,0 +1,101 @@
+#
+# Copyright 2010 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 this program; if not, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+#
+
+"""
+Miscellaneous utilities for managing mods and demods, as well as other items
+useful in dealing with generalized handling of different modulations and demods.
+"""
+
+import inspect
+
+
+# Type 1 modulators accept a stream of bytes on their input and produce complex baseband output
+_type_1_modulators = {}
+
+def type_1_mods():
+    return _type_1_modulators
+
+def add_type_1_mod(name, mod_class):
+    _type_1_modulators[name] = mod_class
+
+
+# Type 1 demodulators accept complex baseband input and produce a stream of bits, packed
+# 1 bit / byte as their output.  Their output is completely unambiguous.  There is no need
+# to resolve phase or polarity ambiguities.
+_type_1_demodulators = {}
+
+def type_1_demods():
+    return _type_1_demodulators
+
+def add_type_1_demod(name, demod_class):
+    _type_1_demodulators[name] = demod_class
+
+# Also record the constellation making functions of the modulations
+_type_1_constellations = {}
+
+def type_1_constellations():
+    return _type_1_constellations
+
+def add_type_1_constellation(name, constellation):
+    _type_1_constellations[name] = constellation
+
+
+def extract_kwargs_from_options(function, excluded_args, options):
+    """
+    Given a function, a list of excluded arguments and the result of
+    parsing command line options, create a dictionary of key word
+    arguments suitable for passing to the function.  The dictionary
+    will be populated with key/value pairs where the keys are those
+    that are common to the function's argument list (minus the
+    excluded_args) and the attributes in options.  The values are the
+    corresponding values from options unless that value is None.
+    In that case, the corresponding dictionary entry is not populated.
+
+    (This allows different modulations that have the same parameter
+    names, but different default values to coexist.  The downside is
+    that --help in the option parser will list the default as None,
+    but in that case the default provided in the __init__ argument
+    list will be used since there is no kwargs entry.)
+
+    @param function: the function whose parameter list will be examined
+    @param excluded_args: function arguments that are NOT to be added to the dictionary
+    @type excluded_args: sequence of strings
+    @param options: result of command argument parsing
+    @type options: optparse.Values
+    """
+    # Try this in C++ ;)
+    args, varargs, varkw, defaults = inspect.getargspec(function)
+    d = {}
+    for kw in [a for a in args if a not in excluded_args]:
+        if hasattr(options, kw):
+            if getattr(options, kw) is not None:
+                d[kw] = getattr(options, kw)
+    return d
+
+def extract_kwargs_from_options_for_class(cls, options):
+    """
+    Given command line options, create dictionary suitable for passing to __init__
+    """
+    d = extract_kwargs_from_options(
+        cls.__init__, ('self',), options)
+    for base in cls.__bases__:
+        if hasattr(base, 'extract_kwargs_from_options'):
+            d.update(base.extract_kwargs_from_options(options))
+    return d
diff --git a/gr-digital/python/ofdm.py b/gr-digital/python/ofdm.py
new file mode 100644
index 000000000..e05f074f4
--- /dev/null
+++ b/gr-digital/python/ofdm.py
@@ -0,0 +1,295 @@
+#!/usr/bin/env python
+#
+# Copyright 2006,2007,2008 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.
+# 
+
+import math
+from gnuradio import gr, ofdm_packet_utils, modulation_utils2
+import gnuradio.gr.gr_threading as _threading
+import psk, qam
+
+from gnuradio.blks2impl.ofdm_receiver import ofdm_receiver
+
+def _add_common_options(normal, expert):
+    """
+    Adds OFDM-specific options to the Options Parser that are common
+    both to the modulator and demodulator.
+    """
+    mods_list = ", ".join(modulation_utils2.type_1_constellations().keys())
+    print dir(modulation_utils2)
+    print "MODS LIST: ", mods_list
+    print modulation_utils2.type_1_mods()
+    normal.add_option("-m", "--modulation", type="string", default="psk",
+                      help="set modulation type (" + mods_list + ") [default=%default]")
+    normal.add_option("-c", "--constellation-points", type="int", default=2,
+                      help="set number of constellation points [default=%default]")
+    expert.add_option("", "--fft-length", type="intx", default=512,
+                      help="set the number of FFT bins [default=%default]")
+    expert.add_option("", "--occupied-tones", type="intx", default=200,
+                      help="set the number of occupied FFT bins [default=%default]")
+    expert.add_option("", "--cp-length", type="intx", default=128,
+                      help="set the number of bits in the cyclic prefix [default=%default]")
+
+# /////////////////////////////////////////////////////////////////////////////
+#                   mod/demod with packets as i/o
+# /////////////////////////////////////////////////////////////////////////////
+
+class ofdm_mod(gr.hier_block2):
+    """
+    Modulates an OFDM stream. Based on the options fft_length, occupied_tones, and
+    cp_length, this block creates OFDM symbols using a specified modulation option.
+    
+    Send packets by calling send_pkt
+    """
+    def __init__(self, options, msgq_limit=2, pad_for_usrp=True):
+        """
+	Hierarchical block for sending packets
+
+        Packets to be sent are enqueued by calling send_pkt.
+        The output is the complex modulated signal at baseband.
+
+        @param options: pass modulation options from higher layers (fft length, occupied tones, etc.)
+        @param msgq_limit: maximum number of messages in message queue
+        @type msgq_limit: int
+        @param pad_for_usrp: If true, packets are padded such that they end up a multiple of 128 samples
+        """
+
+	gr.hier_block2.__init__(self, "ofdm_mod",
+				gr.io_signature(0, 0, 0),       # Input signature
+				gr.io_signature(1, 1, gr.sizeof_gr_complex)) # Output signature
+
+        self._pad_for_usrp = pad_for_usrp
+        self._modulation = options.modulation
+        self._fft_length = options.fft_length
+        self._occupied_tones = options.occupied_tones
+        self._cp_length = options.cp_length
+
+        print (options)
+        arity = options.constellation_points
+
+        win = [] #[1 for i in range(self._fft_length)]
+
+        # Use freq domain to get doubled-up known symbol for correlation in time domain
+        zeros_on_left = int(math.ceil((self._fft_length - self._occupied_tones)/2.0))
+        ksfreq = known_symbols_4512_3[0:self._occupied_tones]
+        for i in range(len(ksfreq)):
+            if((zeros_on_left + i) & 1):
+                ksfreq[i] = 0
+
+        # hard-coded known symbols
+        preambles = (ksfreq,)
+                
+        padded_preambles = list()
+        for pre in preambles:
+            padded = self._fft_length*[0,]
+            padded[zeros_on_left : zeros_on_left + self._occupied_tones] = pre
+            padded_preambles.append(padded)
+            
+        symbol_length = options.fft_length + options.cp_length
+        
+        print modulation_utils2.type_1_constellations
+        const = modulation_utils2.type_1_constellations()[self._modulation](arity).points()
+
+        self._pkt_input = gr.ofdm_mapper_bcv(const, msgq_limit,
+                                             options.occupied_tones, options.fft_length)
+        
+        self.preambles = gr.ofdm_insert_preamble(self._fft_length, padded_preambles)
+        self.ifft = gr.fft_vcc(self._fft_length, False, win, True)
+        self.cp_adder = gr.ofdm_cyclic_prefixer(self._fft_length, symbol_length)
+        self.scale = gr.multiply_const_cc(1.0 / math.sqrt(self._fft_length))
+        
+        self.connect((self._pkt_input, 0), (self.preambles, 0))
+        self.connect((self._pkt_input, 1), (self.preambles, 1))
+        self.connect(self.preambles, self.ifft, self.cp_adder, self.scale, self)
+        
+        if options.verbose:
+            self._print_verbage()
+
+        if options.log:
+            self.connect(self._pkt_input, gr.file_sink(gr.sizeof_gr_complex*options.fft_length,
+                                                       "ofdm_mapper_c.dat"))
+            self.connect(self.preambles, gr.file_sink(gr.sizeof_gr_complex*options.fft_length,
+                                                      "ofdm_preambles.dat"))
+            self.connect(self.ifft, gr.file_sink(gr.sizeof_gr_complex*options.fft_length,
+                                                 "ofdm_ifft_c.dat"))
+            self.connect(self.cp_adder, gr.file_sink(gr.sizeof_gr_complex,
+                                                     "ofdm_cp_adder_c.dat"))
+
+    def send_pkt(self, payload='', eof=False):
+        """
+        Send the payload.
+
+        @param payload: data to send
+        @type payload: string
+        """
+        if eof:
+            msg = gr.message(1) # tell self._pkt_input we're not sending any more packets
+        else:
+            # print "original_payload =", string_to_hex_list(payload)
+            pkt = ofdm_packet_utils.make_packet(payload, 1, 1, self._pad_for_usrp, whitening=True)
+            
+            #print "pkt =", string_to_hex_list(pkt)
+            msg = gr.message_from_string(pkt)
+        self._pkt_input.msgq().insert_tail(msg)
+
+    def add_options(normal, expert):
+        """
+        Adds OFDM-specific options to the Options Parser
+        """
+        _add_common_options(normal, expert)
+        for mod in modulation_utils2.type_1_mods().values():
+            mod.add_options(expert)
+
+    # Make a static method to call before instantiation
+    add_options = staticmethod(add_options)
+
+    def _print_verbage(self):
+        """
+        Prints information about the OFDM modulator
+        """
+        print "\nOFDM Modulator:"
+        print "Modulation Type: %s"    % (self._modulation)
+        print "FFT length:      %3d"   % (self._fft_length)
+        print "Occupied Tones:  %3d"   % (self._occupied_tones)
+        print "CP length:       %3d"   % (self._cp_length)
+
+
+class ofdm_demod(gr.hier_block2):
+    """
+    Demodulates a received OFDM stream. Based on the options fft_length, occupied_tones, and
+    cp_length, this block performs synchronization, FFT, and demodulation of incoming OFDM
+    symbols and passes packets up the a higher layer.
+
+    The input is complex baseband.  When packets are demodulated, they are passed to the
+    app via the callback.
+    """
+
+    def __init__(self, options, callback=None):
+        """
+	Hierarchical block for demodulating and deframing packets.
+
+	The input is the complex modulated signal at baseband.
+        Demodulated packets are sent to the handler.
+
+        @param options: pass modulation options from higher layers (fft length, occupied tones, etc.)
+        @param callback:  function of two args: ok, payload
+        @type callback: ok: bool; payload: string
+	"""
+	gr.hier_block2.__init__(self, "ofdm_demod",
+				gr.io_signature(1, 1, gr.sizeof_gr_complex), # Input signature
+				gr.io_signature(1, 1, gr.sizeof_gr_complex)) # Output signature
+
+
+        self._rcvd_pktq = gr.msg_queue()          # holds packets from the PHY
+
+        self._modulation = options.modulation
+        self._fft_length = options.fft_length
+        self._occupied_tones = options.occupied_tones
+        self._cp_length = options.cp_length
+        self._snr = options.snr
+
+        arity = options.constellation_points
+        print("con points is %s" % options.constellation_points)
+        
+        # Use freq domain to get doubled-up known symbol for correlation in time domain
+        zeros_on_left = int(math.ceil((self._fft_length - self._occupied_tones)/2.0))
+        ksfreq = known_symbols_4512_3[0:self._occupied_tones]
+        for i in range(len(ksfreq)):
+            if((zeros_on_left + i) & 1):
+                ksfreq[i] = 0
+
+        # hard-coded known symbols
+        preambles = (ksfreq,)
+        
+        symbol_length = self._fft_length + self._cp_length
+        self.ofdm_recv = ofdm_receiver(self._fft_length, self._cp_length,
+                                       self._occupied_tones, self._snr, preambles,
+                                       options.log)
+
+        constell = modulation_utils2.type_1_constellations()[self._modulation](arity)
+
+        phgain = 0.25
+        frgain = phgain*phgain / 4.0
+        self.ofdm_demod = gr.ofdm_frame_sink2(constell.base(),
+                                             self._rcvd_pktq,
+                                             self._occupied_tones,
+                                             phgain, frgain)
+
+        self.connect(self, self.ofdm_recv)
+        self.connect((self.ofdm_recv, 0), (self.ofdm_demod, 0))
+        self.connect((self.ofdm_recv, 1), (self.ofdm_demod, 1))
+
+        # added output signature to work around bug, though it might not be a bad
+        # thing to export, anyway
+        self.connect(self.ofdm_recv.chan_filt, self)
+
+        if options.log:
+            self.connect(self.ofdm_demod, gr.file_sink(gr.sizeof_gr_complex*self._occupied_tones, "ofdm_frame_sink_c.dat"))
+        else:
+            self.connect(self.ofdm_demod, gr.null_sink(gr.sizeof_gr_complex*self._occupied_tones))
+
+        if options.verbose:
+            self._print_verbage()
+            
+        self._watcher = _queue_watcher_thread(self._rcvd_pktq, callback)
+
+    def add_options(normal, expert):
+        """
+        Adds OFDM-specific options to the Options Parser
+        """
+        _add_common_options(normal, expert)
+        for mod in modulation_utils2.type_1_mods().values():
+            mod.add_options(expert)
+    # Make a static method to call before instantiation
+    add_options = staticmethod(add_options)
+
+    def _print_verbage(self):
+        """
+        Prints information about the OFDM demodulator
+        """
+        print "\nOFDM Demodulator:"
+        print "Modulation Type: %s"    % (self._modulation)
+        print "FFT length:      %3d"   % (self._fft_length)
+        print "Occupied Tones:  %3d"   % (self._occupied_tones)
+        print "CP length:       %3d"   % (self._cp_length)
+
+
+
+class _queue_watcher_thread(_threading.Thread):
+    def __init__(self, rcvd_pktq, callback):
+        _threading.Thread.__init__(self)
+        self.setDaemon(1)
+        self.rcvd_pktq = rcvd_pktq
+        self.callback = callback
+        self.keep_running = True
+        self.start()
+
+
+    def run(self):
+        while self.keep_running:
+            msg = self.rcvd_pktq.delete_head()
+            ok, payload = ofdm_packet_utils.unmake_packet(msg.to_string())
+            if self.callback:
+                self.callback(ok, payload)
+
+# Generating known symbols with:
+# i = [2*random.randint(0,1)-1 for i in range(4512)]
+
+known_symbols_4512_3 = [-1, -1, 1, -1, 1, 1, -1, -1, 1, -1, 1, 1, -1, 1, -1, -1, 1, -1, 1, -1, 1, 1, -1, -1, -1, 1, -1, 1, 1, -1, 1, -1, -1, -1, -1, -1, -1, -1, 1, 1, -1, -1, 1, 1, 1, -1, 1, -1, -1, -1, 1, 1, 1, 1, 1, 1, 1, -1, -1, 1, -1, 1, -1, -1, 1, -1, 1, 1, 1, 1, -1, 1, -1, 1, -1, 1, -1, -1, -1, 1, -1, -1, -1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, 1, -1, -1, 1, -1, 1, 1, 1, -1, -1, -1, -1, -1, -1, 1, -1, -1, -1, -1, 1, -1, 1, 1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, 1, 1, 1, 1, -1, -1, 1, -1, 1, -1, 1, 1, 1, 1, -1, -1, 1, -1, 1, 1, 1, 1, -1, 1, -1, -1, 1, -1, 1, 1, 1, -1, -1, -1, 1, 1, 1, 1, 1, 1, -1, -1, 1, 1, 1, -1, -1, 1, -1, -1, 1, 1, 1, -1, -1, 1, 1, -1, 1, -1, -1, -1, -1, -1, -1, 1, 1, -1, -1, 1, -1, -1, 1, -1, 1, -1, -1, 1, 1, -1, 1, 1, 1, 1, -1, 1, 1, 1, -1, 1, -1, 1, 1, 1, -1, 1, 1, -1, 1, 1, 1, -1, 1, 1, 1, 1, -1, 1, -1, -1, 1, -1, -1, 1, 1, 1, -1, 1, -1, -1, -1, -1, -1, 1, -1, 1, -1, 1, 1, 1, 1, -1, 1, -1, -1, -1, 1, -1, 1, 1, -1, -1, -1, 1, 1, -1, -1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, 1, -1, 1, 1, 1, 1, -1, 1, -1, 1, 1, 1, -1, -1, 1, -1, 1, -1, -1, -1, -1, -1, 1, 1, -1, 1, 1, 1, -1, 1, -1, 1, 1, -1, -1, -1, 1, -1, -1, 1, -1, -1, 1, 1, -1, 1, 1, -1, 1, 1, -1, -1, 1, 1, -1, 1, 1, -1, 1, 1, 1, -1, -1, 1, 1, 1, -1, 1, 1, -1, 1, 1, 1, -1, 1, -1, 1, 1, -1, -1, 1, -1, -1, -1, 1, 1, -1, -1, 1, -1, -1, 1, -1, 1, 1, -1, -1, -1, -1, 1, -1, -1, 1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, -1, -1, -1, 1, -1, 1, 1, 1, 1, 1, 1, 1, -1, -1, 1, -1, 1, -1, -1, 1, -1, 1, 1, -1, 1, -1, 1, 1, -1, 1, -1, -1, -1, 1, 1, -1, 1, 1, 1, 1, -1, 1, -1, -1, -1, 1, -1, -1, 1, 1, 1, -1, 1, -1, 1, 1, -1, -1, -1, -1, 1, -1, 1, -1, -1, -1, 1, 1, -1, -1, 1, -1, -1, 1, 1, -1, -1, 1, -1, -1, 1, -1, -1, -1, 1, -1, 1, -1, 1, 1, 1, 1, 1, 1, -1, -1, 1, -1, 1, -1, -1, -1, -1, -1, 1, 1, -1, 1, 1, 1, 1, -1, 1, 1, 1, -1, -1, 1, 1, 1, -1, 1, 1, 1, 1, 1, -1, 1, -1, -1, -1, -1, -1, -1, 1, 1, -1, -1, 1, -1, 1, 1, 1, 1, -1, 1, -1, 1, -1, -1, 1, -1, -1, -1, -1, 1, 1, -1, 1, 1, 1, -1, -1, 1, 1, 1, -1, -1, -1, -1, 1, -1, 1, -1, 1, -1, -1, -1, -1, -1, -1, 1, 1, -1, 1, 1, 1, 1, 1, -1, -1, -1, 1, 1, 1, 1, 1, 1, 1, 1, -1, 1, 1, 1, 1, 1, 1, -1, 1, -1, 1, -1, -1, -1, 1, 1, -1, 1, 1, 1, -1, 1, -1, -1, 1, 1, 1, 1, -1, 1, 1, 1, 1, 1, 1, -1, -1, -1, 1, 1, 1, -1, 1, 1, -1, -1, -1, -1, 1, 1, 1, -1, 1, 1, -1, 1, 1, -1, -1, -1, -1, -1, -1, -1, 1, 1, 1, 1, -1, -1, 1, -1, -1, 1, 1, -1, -1, -1, -1, -1, -1, 1, 1, -1, -1, 1, 1, -1, 1, -1, -1, -1, -1, 1, -1, 1, -1, 1, 1, 1, -1, 1, 1, -1, -1, 1, 1, 1, 1, -1, -1, 1, -1, -1, -1, 1, -1, -1, -1, 1, 1, -1, -1, -1, 1, -1, 1, -1, 1, 1, -1, 1, -1, 1, 1, 1, -1, 1, 1, 1, -1, -1, 1, -1, -1, -1, -1, 1, 1, 1, 1, 1, -1, 1, -1, -1, 1, 1, -1, 1, -1, 1, -1, -1, 1, -1, -1, -1, 1, 1, -1, -1, 1, 1, 1, -1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1, 1, -1, -1, 1, 1, -1, -1, 1, -1, 1, 1, 1, -1, -1, 1, 1, -1, 1, -1, -1, -1, 1, -1, -1, -1, 1, 1, -1, 1, -1, 1, 1, -1, 1, -1, -1, 1, 1, 1, -1, -1, -1, 1, 1, -1, 1, 1, 1, 1, -1, 1, 1, -1, -1, 1, 1, 1, -1, 1, 1, 1, -1, 1, 1, 1, 1, 1, -1, 1, 1, -1, 1, 1, -1, -1, 1, 1, -1, 1, -1, -1, 1, -1, 1, 1, 1, 1, -1, -1, -1, 1, 1, -1, -1, -1, -1, -1, 1, -1, -1, 1, 1, -1, -1, 1, 1, -1, -1, 1, -1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, -1, -1, 1, 1, -1, 1, -1, -1, -1, 1, -1, -1, 1, 1, 1, -1, -1, 1, -1, 1, 1, 1, -1, -1, 1, -1, -1, 1, 1, 1, -1, -1, 1, -1, 1, 1, -1, 1, 1, 1, 1, 1, 1, 1, 1, -1, 1, -1, -1, 1, -1, 1, -1, -1, -1, -1, 1, -1, -1, 1, 1, -1, 1, -1, -1, -1, -1, -1, 1, 1, 1, 1, -1, 1, 1, 1, 1, 1, 1, -1, 1, 1, 1, 1, -1, -1, -1, -1, 1, -1, -1, 1, 1, -1, 1, 1, -1, 1, -1, 1, -1, -1, 1, -1, 1, -1, -1, 1, -1, -1, 1, 1, 1, -1, 1, 1, 1, 1, 1, -1, 1, -1, -1, 1, -1, 1, -1, -1, 1, 1, -1, 1, -1, -1, -1, -1, 1, -1, 1, -1, 1, 1, 1, -1, -1, 1, -1, -1, -1, -1, -1, -1, -1, -1, 1, -1, -1, 1, 1, 1, 1, -1, -1, 1, 1, -1, -1, 1, -1, -1, 1, -1, 1, 1, -1, 1, 1, 1, -1, 1, 1, 1, 1, 1, 1, 1, 1, 1, -1, 1, -1, 1, -1, 1, -1, -1, 1, 1, 1, 1, 1, 1, -1, 1, -1, -1, 1, -1, 1, 1, -1, 1, 1, 1, -1, -1, 1, 1, -1, 1, 1, 1, -1, -1, 1, -1, 1, 1, -1, 1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 1, 1, 1, -1, 1, 1, -1, 1, -1, 1, -1, 1, 1, -1, 1, -1, 1, 1, -1, 1, 1, 1, -1, -1, 1, -1, 1, -1, -1, -1, 1, -1, -1, -1, 1, -1, -1, 1, -1, 1, -1, 1, 1, 1, 1, 1, -1, 1, 1, 1, 1, -1, 1, -1, 1, 1, -1, 1, -1, 1, 1, -1, -1, 1, -1, 1, 1, 1, -1, 1, -1, 1, 1, -1, 1, 1, 1, -1, 1, 1, 1, -1, -1, 1, -1, -1, 1, 1, -1, -1, 1, 1, -1, -1, -1, -1, -1, 1, -1, 1, 1, -1, -1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, 1, -1, 1, 1, 1, -1, 1, 1, 1, -1, 1, 1, -1, 1, -1, -1, -1, 1, -1, 1, -1, 1, 1, -1, 1, -1, -1, 1, -1, 1, -1, -1, -1, 1, -1, 1, 1, 1, 1, -1, -1, 1, -1, 1, -1, 1, 1, -1, -1, 1, 1, 1, -1, 1, -1, -1, -1, -1, -1, 1, -1, 1, -1, -1, 1, -1, 1, 1, 1, 1, 1, -1, 1, 1, -1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, 1, -1, 1, -1, 1, -1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, 1, -1, 1, 1, -1, -1, 1, 1, -1, 1, -1, -1, -1, 1, 1, 1, 1, 1, -1, -1, -1, 1, 1, 1, 1, 1, 1, -1, 1, -1, 1, -1, -1, 1, 1, 1, 1, -1, -1, 1, -1, 1, 1, 1, 1, -1, 1, 1, 1, 1, -1, 1, 1, -1, 1, -1, 1, -1, -1, 1, -1, -1, -1, -1, 1, -1, 1, -1, 1, 1, 1, 1, 1, -1, 1, -1, 1, 1, 1, -1, -1, 1, 1, 1, 1, -1, -1, 1, 1, -1, 1, 1, 1, 1, -1, -1, 1, 1, 1, -1, 1, 1, -1, -1, -1, -1, 1, 1, 1, 1, 1, -1, -1, 1, -1, 1, 1, 1, -1, -1, -1, -1, -1, -1, 1, -1, 1, -1, -1, -1, 1, -1, 1, -1, 1, -1, -1, -1, 1, -1, 1, -1, 1, 1, 1, -1, -1, -1, -1, 1, -1, 1, -1, -1, -1, -1, -1, -1, -1, -1, 1, 1, -1, 1, -1, 1, 1, -1, 1, -1, 1, 1, 1, -1, 1, -1, -1, 1, 1, 1, -1, 1, 1, 1, -1, -1, 1, -1, -1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 1, -1, 1, -1, -1, 1, -1, 1, -1, 1, 1, 1, 1, 1, 1, -1, 1, -1, 1, -1, -1, 1, -1, 1, -1, -1, -1, 1, 1, 1, 1, -1, 1, 1, 1, -1, -1, 1, 1, 1, 1, 1, -1, 1, -1, -1, -1, -1, -1, 1, 1, 1, -1, 1, -1, 1, -1, -1, -1, 1, -1, -1, -1, 1, 1, 1, 1, -1, -1, -1, 1, -1, -1, 1, 1, 1, -1, -1, -1, -1, -1, -1, 1, -1, 1, -1, 1, 1, 1, 1, -1, -1, 1, 1, -1, 1, 1, 1, -1, 1, -1, -1, -1, 1, -1, 1, 1, -1, -1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, 1, -1, -1, -1, 1, -1, 1, -1, -1, 1, 1, -1, 1, -1, -1, -1, -1, 1, -1, 1, 1, -1, -1, -1, 1, 1, 1, 1, 1, -1, -1, -1, 1, -1, -1, 1, 1, -1, -1, -1, 1, -1, 1, 1, 1, -1, -1, 1, 1, -1, -1, -1, 1, -1, 1, -1, -1, -1, -1, -1, -1, 1, 1, 1, 1, 1, 1, -1, -1, 1, -1, 1, 1, -1, -1, -1, -1, 1, -1, -1, 1, -1, 1, 1, 1, -1, 1, -1, 1, -1, 1, -1, -1, -1, 1, -1, -1, -1, 1, -1, -1, 1, -1, 1, -1, -1, 1, -1, 1, 1, 1, 1, 1, -1, -1, -1, 1, 1, -1, 1, 1, 1, -1, -1, 1, 1, -1, -1, 1, -1, -1, 1, 1, -1, -1, -1, -1, 1, -1, -1, 1, -1, -1, -1, 1, 1, -1, -1, 1, -1, 1, -1, -1, 1, -1, -1, 1, -1, 1, -1, 1, 1, 1, -1, 1, 1, -1, -1, -1, 1, 1, -1, 1, 1, -1, 1, 1, 1, 1, 1, -1, 1, -1, -1, 1, 1, -1, 1, 1, 1, -1, -1, 1, -1, -1, -1, -1, -1, 1, -1, 1, 1, 1, 1, -1, 1, -1, 1, 1, -1, 1, -1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, 1, 1, 1, -1, 1, -1, -1, -1, -1, 1, -1, -1, 1, 1, 1, -1, 1, -1, 1, 1, -1, -1, 1, -1, 1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, 1, -1, 1, 1, -1, 1, -1, -1, 1, -1, -1, -1, 1, 1, 1, -1, 1, -1, -1, 1, -1, -1, -1, -1, -1, -1, 1, -1, -1, -1, -1, 1, -1, 1, 1, 1, -1, 1, -1, -1, -1, 1, 1, -1, 1, -1, -1, -1, -1, 1, -1, -1, -1, -1, 1, -1, 1, 1, -1, 1, 1, -1, 1, 1, 1, -1, 1, 1, 1, -1, 1, 1, 1, -1, -1, -1, -1, 1, -1, -1, -1, -1, -1, 1, -1, -1, 1, -1, 1, -1, 1, -1, -1, 1, -1, 1, -1, -1, 1, 1, -1, -1, 1, 1, -1, -1, 1, 1, -1, 1, 1, -1, 1, -1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, 1, 1, 1, -1, 1, -1, -1, -1, -1, 1, -1, -1, -1, -1, 1, -1, 1, 1, -1, -1, -1, 1, -1, 1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 1, 1, 1, -1, -1, 1, -1, 1, -1, 1, -1, -1, -1, -1, -1, -1, -1, -1, 1, 1, -1, -1, 1, 1, 1, -1, -1, 1, -1, 1, 1, 1, -1, 1, -1, 1, 1, 1, -1, 1, 1, -1, 1, 1, -1, 1, -1, -1, 1, 1, 1, -1, 1, -1, -1, 1, -1, -1, -1, 1, -1, -1, 1, -1, -1, 1, 1, -1, -1, -1, 1, 1, -1, -1, 1, 1, -1, -1, -1, 1, 1, -1, 1, 1, 1, -1, 1, -1, -1, 1, 1, 1, 1, -1, 1, 1, 1, -1, 1, -1, 1, 1, 1, 1, -1, -1, 1, 1, 1, -1, 1, -1, 1, -1, -1, -1, -1, 1, -1, 1, -1, -1, -1, 1, -1, -1, -1, 1, 1, -1, 1, 1, 1, 1, -1, 1, 1, 1, 1, -1, -1, -1, 1, -1, -1, 1, 1, 1, -1, 1, -1, -1, -1, 1, 1, 1, 1, 1, 1, 1, -1, 1, -1, -1, -1, 1, 1, -1, -1, -1, -1, -1, 1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 1, -1, 1, 1, -1, 1, -1, -1, -1, 1, -1, 1, -1, 1, -1, -1, 1, -1, -1, 1, -1, 1, -1, 1, -1, -1, 1, -1, 1, 1, 1, -1, 1, -1, 1, 1, -1, -1, -1, 1, -1, 1, 1, 1, 1, -1, -1, 1, 1, 1, -1, -1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, 1, 1, -1, 1, 1, -1, 1, -1, -1, -1, 1, 1, -1, -1, -1, -1, 1, 1, -1, -1, 1, 1, -1, 1, -1, -1, -1, 1, -1, -1, -1, -1, -1, -1, -1, 1, 1, -1, -1, -1, 1, -1, 1, -1, 1, -1, 1, -1, -1, 1, 1, -1, 1, 1, 1, -1, 1, 1, -1, 1, 1, -1, -1, -1, 1, 1, -1, -1, -1, -1, 1, -1, -1, -1, 1, 1, 1, -1, 1, 1, 1, 1, -1, -1, -1, -1, -1, 1, 1, 1, 1, -1, -1, 1, -1, 1, -1, 1, -1, 1, 1, 1, -1, 1, 1, 1, -1, 1, 1, 1, -1, 1, 1, -1, -1, 1, -1, -1, 1, -1, -1, -1, 1, 1, 1, 1, 1, 1, 1, -1, -1, 1, 1, 1, 1, -1, -1, 1, -1, 1, -1, 1, -1, 1, -1, -1, 1, -1, 1, -1, -1, -1, -1, 1, 1, -1, 1, 1, 1, 1, -1, -1, 1, 1, -1, -1, 1, -1, -1, -1, 1, 1, -1, -1, -1, -1, 1, 1, 1, -1, -1, -1, -1, -1, -1, 1, -1, -1, -1, -1, -1, -1, 1, 1, -1, -1, -1, -1, 1, -1, -1, -1, 1, 1, 1, -1, 1, -1, -1, -1, -1, -1, -1, 1, -1, 1, 1, -1, 1, 1, 1, 1, -1, 1, 1, 1, 1, 1, -1, -1, 1, 1, -1, -1, -1, -1, -1, -1, -1, 1, 1, -1, 1, -1, -1, -1, 1, 1, 1, 1, 1, 1, -1, -1, 1, 1, -1, 1, -1, -1, 1, -1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, 1, -1, 1, 1, -1, -1, 1, -1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, -1, 1, -1, 1, 1, -1, 1, -1, -1, -1, 1, -1, -1, -1, 1, 1, -1, -1, 1, -1, 1, 1, 1, -1, -1, -1, -1, -1, 1, 1, 1, -1, -1, 1, -1, 1, 1, 1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, -1, -1, 1, -1, 1, -1, 1, -1, 1, -1, -1, 1, -1, 1, 1, -1, 1, -1, 1, -1, 1, 1, -1, 1, -1, 1, -1, -1, 1, -1, -1, -1, 1, -1, -1, 1, 1, -1, -1, 1, -1, 1, -1, 1, 1, 1, 1, -1, 1, 1, -1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, 1, -1, -1, 1, -1, 1, 1, -1, -1, 1, -1, -1, -1, 1, -1, 1, 1, -1, 1, 1, 1, 1, 1, -1, 1, 1, 1, -1, 1, -1, 1, -1, 1, -1, -1, 1, -1, 1, -1, -1, -1, 1, 1, -1, -1, 1, -1, 1, -1, 1, -1, 1, 1, 1, -1, 1, -1, 1, -1, 1, -1, 1, 1, 1, -1, 1, -1, 1, -1, 1, 1, 1, 1, -1, 1, 1, 1, -1, -1, -1, -1, -1, 1, -1, 1, -1, -1, 1, 1, 1, -1, -1, -1, 1, -1, -1, 1, -1, -1, -1, 1, -1, 1, -1, 1, 1, -1, 1, -1, 1, -1, -1, 1, -1, 1, -1, -1, 1, -1, -1, 1, -1, -1, 1, -1, -1, -1, -1, 1, -1, 1, 1, 1, -1, -1, -1, -1, 1, 1, 1, -1, -1, 1, -1, 1, -1, -1, -1, 1, 1, -1, 1, 1, -1, -1, 1, 1, 1, -1, -1, -1, 1, -1, 1, 1, -1, -1, -1, -1, -1, -1, 1, 1, -1, 1, -1, -1, -1, -1, 1, 1, 1, -1, 1, 1, 1, 1, -1, 1, -1, -1, -1, 1, 1, -1, -1, -1, 1, -1, 1, -1, 1, -1, -1, 1, -1, 1, 1, -1, -1, 1, -1, -1, -1, 1, -1, 1, 1, -1, -1, -1, 1, -1, 1, -1, -1, -1, -1, 1, 1, -1, 1, 1, -1, 1, 1, 1, -1, -1, -1, -1, -1, 1, 1, -1, 1, -1, 1, -1, -1, -1, -1, -1, 1, 1, -1, -1, 1, 1, 1, 1, -1, -1, 1, 1, 1, -1, 1, 1, 1, -1, 1, -1, -1, -1, -1, 1, 1, -1, -1, 1, -1, -1, 1, -1, -1, -1, 1, 1, 1, -1, -1, 1, -1, 1, 1, -1, -1, 1, -1, -1, -1, -1, -1, -1, 1, -1, 1, -1, -1, 1, -1, -1, -1, 1, 1, 1, 1, -1, 1, 1, -1, -1, 1, -1, 1, -1, 1, 1, -1, 1, 1, -1, 1, 1, 1, 1, -1, -1, -1, 1, -1, -1, 1, 1, -1, -1, 1, -1, -1, 1, 1, 1, -1, -1, -1, -1, -1, 1, -1, -1, 1, 1, 1, 1, -1, -1, -1, -1, 1, 1, -1, -1, 1, -1, -1, -1, 1, -1, 1, -1, -1, 1, 1, 1, -1, 1, -1, 1, -1, -1, -1, -1, -1, 1, -1, 1, 1, -1, -1, 1, 1, 1, 1, -1, 1, -1, 1, 1, -1, -1, 1, 1, 1, -1, -1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1, 1, -1, -1, -1, -1, 1, -1, 1, 1, 1, 1, -1, 1, -1, 1, 1, 1, 1, -1, 1, 1, 1, 1, -1, 1, -1, -1, -1, -1, 1, 1, 1, -1, 1, 1, 1, 1, -1, -1, 1, 1, -1, 1, -1, 1, -1, -1, 1, 1, -1, -1, -1, -1, 1, -1, -1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, 1, -1, -1, -1, -1, -1, 1, 1, -1, 1, -1, -1, -1, 1, 1, -1, 1, -1, -1, -1, 1, -1, 1, -1, -1, 1, -1, -1, -1, -1, 1, -1, -1, -1, 1, -1, -1, 1, -1, -1, -1, -1, -1, -1, 1, -1, 1, 1, -1, 1, -1, 1, 1, -1, 1, -1, -1, -1, -1, 1, -1, -1, -1, 1, 1, -1, -1, 1, 1, -1, -1, 1, 1, 1, 1, 1, 1, 1, 1, 1, -1, -1, 1, -1, -1, -1, -1, -1, -1, -1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, 1, 1, -1, -1, 1, 1, -1, -1, 1, 1, 1, 1, -1, 1, -1, -1, 1, -1, 1, -1, -1, -1, -1, 1, 1, -1, -1, 1, -1, 1, 1, 1, 1, -1, -1, 1, 1, -1, 1, 1, -1, 1, 1, -1, -1, -1, 1, -1, 1, 1, -1, -1, 1, -1, 1, 1, -1, -1, 1, 1, 1, -1, 1, 1, -1, -1, 1, 1, -1, -1, 1, 1, 1, 1, 1, -1, 1, -1, 1, -1, 1, 1, 1, -1, 1, -1, 1, 1, 1, -1, 1, 1, 1, 1, -1, -1, 1, -1, 1, -1, -1, -1, -1, 1, 1, -1, 1, -1, 1, -1, 1, 1, 1, 1, -1, -1, 1, 1, -1, 1, -1, 1, -1, 1, 1, 1, -1, -1, -1, 1, -1, -1, -1, 1, 1, 1, 1, 1, -1, 1, 1, 1, 1, -1, -1, -1, 1, 1, -1, -1, 1, -1, -1, -1, 1, 1, -1, -1, 1, 1, -1, -1, -1, 1, 1, -1, -1, 1, -1, 1, -1, -1, 1, 1, -1, -1, 1, -1, 1, 1, 1, 1, -1, -1, -1, -1, 1, -1, -1, -1, -1, 1, 1, -1, -1, -1, -1, 1, -1, -1, -1, -1, -1, 1, 1, -1, 1, -1, -1, 1, -1, 1, -1, 1, 1, -1, -1, -1, 1, 1, -1, 1, 1, -1, -1, 1, 1, -1, 1, 1, -1, 1, 1, 1, -1, 1, -1, -1, 1, -1, 1, 1, 1, -1, -1, -1, 1, 1, 1, -1, 1, -1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1, 1, -1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, 1, -1, 1, 1, -1, -1, -1, -1, 1, -1, 1, -1, 1, 1, 1, 1, -1, 1, -1, -1, -1, -1, 1, -1, -1, -1, -1, 1, 1, -1, 1, -1, 1, 1, -1, -1, 1, -1, -1, -1, -1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1, 1, -1, -1, 1, -1, 1, -1, 1, 1, 1, -1, -1, 1, 1, 1, 1, -1, -1, 1, 1, 1, 1, -1, -1, 1, 1, 1, 1, 1, 1, -1, -1, 1, -1, 1, 1, -1, 1, -1, 1, 1, -1, -1, 1, 1, -1, 1, -1, -1, 1, -1, -1, -1, -1, 1, -1, -1, -1, -1, -1, 1, 1, -1, 1, -1, -1, -1, -1, 1, 1, -1, 1, 1, -1, -1, 1, 1, -1, 1, -1, 1, -1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, 1, 1, -1, -1, 1, -1, 1, -1, -1, -1, -1, -1, -1, 1, -1, 1, 1, -1, 1, -1, -1, -1, 1, 1, -1, 1, -1, -1, 1, -1, 1, 1, -1, 1, -1, -1, 1, -1, 1, -1, 1, -1, -1, 1, -1, -1, -1, 1, 1, -1, -1, 1, -1, -1, 1, -1, -1, -1, 1, -1, 1, 1, -1, -1, -1, -1, -1, 1, -1, 1, 1, -1, 1, 1, -1, -1, 1, 1, 1, -1, 1, 1, 1, -1, 1, 1, -1, -1, 1, 1, 1, 1, 1, 1, -1, -1, -1, 1, 1, -1, -1, -1, -1, 1, 1, -1, -1, 1, 1, -1, 1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, -1, 1, 1, -1, 1, -1, 1, -1, 1, -1, 1, 1, -1, -1, -1, -1, 1, 1, -1, 1, -1, -1, 1, 1, -1, 1, 1, -1, -1, -1, 1, 1, 1, -1, 1, 1, 1, -1, 1, 1, -1, 1, 1, -1, 1, -1, -1, 1, 1, 1, -1, 1, -1, 1, 1, 1, 1, -1, -1, -1, 1, -1, 1, -1, -1, 1, -1, 1, 1, -1, -1, -1, 1, -1, 1, -1, 1, 1, 1, -1, 1, 1, -1, 1, 1, -1, -1, -1, -1, 1, -1, 1, 1, -1, -1, 1, 1, -1, 1, -1, -1, -1, 1, 1, 1, -1, -1, 1, -1, -1, -1, 1, 1, 1, 1, -1, -1, -1, 1, -1, 1, 1, 1, -1, 1, 1, 1, -1, -1, -1, 1, 1, -1, -1, 1, 1, -1, 1, -1, -1, 1, -1, -1, -1, 1, 1, -1, 1, -1, -1, 1, 1, -1, 1, -1, -1, 1, -1, -1, -1, 1, 1, -1, 1, 1, -1, 1, -1, -1, -1, -1, 1, -1, -1, 1, 1, -1, 1, 1, 1, 1, 1, -1, 1, -1, 1, 1, 1, 1, -1, -1, 1, 1, -1, 1, -1, 1, -1, -1, 1, -1, -1, -1, 1, -1, -1, -1, 1, 1, 1, -1, -1, 1, 1, -1, -1, -1, -1, 1, -1, 1, -1, 1, 1, 1, -1, 1, 1, -1, 1, -1, 1, -1, -1, 1, -1, -1, -1, -1, 1, 1, -1, -1, 1, -1, -1, 1, 1, 1, -1, -1, -1, -1, 1, -1, -1, 1, -1, 1, 1, 1, 1, 1, -1, -1, -1, -1, 1, -1, -1, -1, 1, 1, 1, 1, -1, -1, -1, -1, 1, -1, -1, 1, 1, 1, -1, 1, -1, 1, -1, 1, 1, -1, -1, -1, 1, 1, 1, 1, -1, -1, -1, 1, 1, -1, 1, 1, 1, 1, 1, -1, 1, 1, -1, 1, 1, 1, -1, 1, -1, -1, 1, 1, -1, 1, -1, 1, -1, 1, 1, -1, -1, -1, 1, 1, -1, 1, -1, 1, -1, -1, -1, -1, 1, 1, 1, 1, -1, 1, -1, 1, -1, -1, -1, 1, -1, -1, 1, -1, 1, 1, -1, -1, -1, -1, 1, 1, -1, -1, 1, -1, 1, -1, -1, 1, -1, 1, -1, -1, 1, -1, -1, 1, 1, -1, 1, -1, -1, 1, -1, 1, -1, 1, -1, 1, 1, -1, -1, 1, 1, -1, 1, -1, -1, 1, 1, 1, 1, -1, -1, -1, -1, 1, -1, 1, -1, 1, -1, -1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, 1, 1, -1, 1, -1, 1, -1, 1, -1, -1, 1, -1, 1, 1, 1, 1, -1, -1, -1, -1, 1, -1, -1, 1, -1, -1, -1, 1, 1, 1, 1, 1, 1, 1, -1, 1, -1, 1, -1, -1, -1, 1, 1, 1, 1, -1, -1, 1, 1, 1, -1, 1, -1, -1, 1, -1, 1, 1, 1, -1, 1, 1, -1, 1, -1, 1, -1, 1, 1, -1, 1, 1, -1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 1, 1, 1, -1, 1, -1, 1, -1, -1, -1, 1, -1, -1, 1, -1, -1, 1, 1, 1, 1, 1, 1, -1, 1, 1, -1, 1, -1, 1, -1, -1, -1, 1, 1, -1, 1, -1, 1, -1, 1, -1, 1, 1, 1, 1, -1, 1, 1, -1, -1, -1, 1, -1, 1, -1, 1, 1, 1, 1, -1, 1, 1, 1, 1, -1, 1, -1, -1, -1, -1, -1, -1, -1, 1, -1, -1, -1, -1, -1, 1, 1, -1, 1, -1]
diff --git a/gr-digital/python/pkt.py b/gr-digital/python/pkt.py
new file mode 100644
index 000000000..aa720d1a5
--- /dev/null
+++ b/gr-digital/python/pkt.py
@@ -0,0 +1,184 @@
+#
+# Copyright 2005, 2006, 2007 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.
+# 
+
+from math import pi
+from gnuradio import gr, packet_utils
+import gnuradio.gr.gr_threading as _threading
+
+
+# /////////////////////////////////////////////////////////////////////////////
+#                   mod/demod with packets as i/o
+# /////////////////////////////////////////////////////////////////////////////
+
+class mod_pkts(gr.hier_block2):
+    """
+    Wrap an arbitrary digital modulator in our packet handling framework.
+
+    Send packets by calling send_pkt
+    """
+    def __init__(self, modulator, access_code=None, msgq_limit=2, pad_for_usrp=True, use_whitener_offset=False,
+                 modulate=True):
+        """
+	Hierarchical block for sending packets
+
+        Packets to be sent are enqueued by calling send_pkt.
+        The output is the complex modulated signal at baseband.
+
+        @param modulator: instance of modulator class (gr_block or hier_block2)
+        @type modulator: complex baseband out
+        @param access_code: AKA sync vector
+        @type access_code: string of 1's and 0's between 1 and 64 long
+        @param msgq_limit: maximum number of messages in message queue
+        @type msgq_limit: int
+        @param pad_for_usrp: If true, packets are padded such that they end up a multiple of 128 samples
+        @param use_whitener_offset: If true, start of whitener XOR string is incremented each packet
+        @param modulate: If false, no modulation will be performed.
+        
+        See gmsk_mod for remaining parameters
+        """
+        if modulate:
+            output_size = gr.sizeof_gr_complex
+        else:
+            output_size = gr.sizeof_char
+
+	gr.hier_block2.__init__(self, "mod_pkts",
+				gr.io_signature(0, 0, 0),                    # Input signature
+				gr.io_signature(1, 1, output_size))          # Output signature
+
+        self._modulator = modulator
+        self._pad_for_usrp = pad_for_usrp
+        self._use_whitener_offset = use_whitener_offset
+        self._whitener_offset = 0
+        
+        if access_code is None:
+            access_code = packet_utils.default_access_code
+        if not packet_utils.is_1_0_string(access_code):
+            raise ValueError, "Invalid access_code %r. Must be string of 1's and 0's" % (access_code,)
+        self._access_code = access_code
+
+        # accepts messages from the outside world
+        self._pkt_input = gr.message_source(gr.sizeof_char, msgq_limit)
+        if modulate:
+            self.connect(self._pkt_input, self._modulator, self)
+        else:
+            self.connect(self._pkt_input, self)
+
+    def send_pkt(self, payload='', eof=False):
+        """
+        Send the payload.
+
+        @param payload: data to send
+        @type payload: string
+        """
+        if eof:
+            msg = gr.message(1) # tell self._pkt_input we're not sending any more packets
+        else:
+            # print "original_payload =", string_to_hex_list(payload)
+            pkt = packet_utils.make_packet(payload,
+                                           self._modulator.samples_per_symbol(),
+                                           self._modulator.bits_per_symbol(),
+                                           self._access_code,
+                                           self._pad_for_usrp,
+                                           self._whitener_offset)
+            #print "pkt =", string_to_hex_list(pkt)
+            msg = gr.message_from_string(pkt)
+            if self._use_whitener_offset is True:
+                self._whitener_offset = (self._whitener_offset + 1) % 16
+                
+        self._pkt_input.msgq().insert_tail(msg)
+
+
+
+class demod_pkts(gr.hier_block2):
+    """
+    Wrap an arbitrary digital demodulator in our packet handling framework.
+
+    The input is complex baseband.  When packets are demodulated, they are passed to the
+    app via the callback.
+    """
+
+    def __init__(self, demodulator, access_code=None, callback=None, threshold=-1, demodulate=True):
+        """
+	Hierarchical block for demodulating and deframing packets.
+
+	The input is the complex modulated signal at baseband.
+        Demodulated packets are sent to the handler.
+
+        If demodulator is None it is assumed the input is already demodulated.
+
+        @param demodulator: instance of demodulator class (gr_block or hier_block2)
+        @type demodulator: complex baseband in
+        @param access_code: AKA sync vector
+        @type access_code: string of 1's and 0's
+        @param callback:  function of two args: ok, payload
+        @type callback: ok: bool; payload: string
+        @param threshold: detect access_code with up to threshold bits wrong (-1 -> use default)
+        @type threshold: int
+	"""
+
+        if demodulator is not None:
+            input_size = gr.sizeof_gr_complex
+        else:
+            input_size = gr.sizeof_char
+
+	gr.hier_block2.__init__(self, "demod_pkts",
+				gr.io_signature(1, 1, input_size), # Input signature
+				gr.io_signature(0, 0, 0))          # Output signature
+
+        self._demodulator = demodulator
+        if access_code is None:
+            access_code = packet_utils.default_access_code
+        if not packet_utils.is_1_0_string(access_code):
+            raise ValueError, "Invalid access_code %r. Must be string of 1's and 0's" % (access_code,)
+        self._access_code = access_code
+
+        if threshold == -1:
+            threshold = 12              # FIXME raise exception
+
+        self._rcvd_pktq = gr.msg_queue()          # holds packets from the PHY
+        self.correlator = gr.correlate_access_code_bb(access_code, threshold)
+
+        self.framer_sink = gr.framer_sink_1(self._rcvd_pktq)
+        if self._demodulator is not None:
+            self.connect(self, self._demodulator, self.correlator, self.framer_sink)
+        else:
+            self.connect(self, self.correlator, self.framer_sink)
+        
+        if callback is not None:
+            self._watcher = _queue_watcher_thread(self._rcvd_pktq, callback)
+
+
+class _queue_watcher_thread(_threading.Thread):
+    def __init__(self, rcvd_pktq, callback):
+        _threading.Thread.__init__(self)
+        self.setDaemon(1)
+        self.rcvd_pktq = rcvd_pktq
+        self.callback = callback
+        self.keep_running = True
+        self.start()
+
+
+    def run(self):
+        while self.keep_running:
+            msg = self.rcvd_pktq.delete_head()
+            ok, payload = packet_utils.unmake_packet(msg.to_string(), int(msg.arg1()))
+            if self.callback:
+                self.callback(ok, payload)