Adding DQPSK version that uses the PFB timing sync block (dqpsk2).

1 files changed, 358 insertions, 0 deletions

diff --git a/gnuradio-core/src/python/gnuradio/blks2impl/dqpsk2.py b/gnuradio-core/src/python/gnuradio/blks2impl/dqpsk2.py
new file mode 100644
index 000000000..05363bf04
--- /dev/null
+++ b/gnuradio-core/src/python/gnuradio/blks2impl/dqpsk2.py
@@ -0,0 +1,358 @@
+#
+# Copyright 2005,2006,2007,2009 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.
+# 
+
+# See gnuradio-examples/python/digital for examples
+
+"""
+differential QPSK modulation and demodulation.
+"""
+
+from gnuradio import gr, gru, modulation_utils
+from math import pi, sqrt
+import psk
+import cmath
+from pprint import pprint
+
+# default values (used in __init__ and add_options)
+_def_samples_per_symbol = 2
+_def_excess_bw = 0.35
+_def_gray_code = True
+_def_verbose = False
+_def_log = False
+
+_def_costas_alpha = 0.01
+_def_timing_alpha = None
+_def_timing_beta = None
+_def_timing_max_dev = 1.5
+
+
+# /////////////////////////////////////////////////////////////////////////////
+#                           DQPSK modulator
+# /////////////////////////////////////////////////////////////////////////////
+
+class dqpsk2_mod(gr.hier_block2):
+
+    def __init__(self,
+                 samples_per_symbol=_def_samples_per_symbol,
+                 excess_bw=_def_excess_bw,
+                 gray_code=_def_gray_code,
+                 verbose=_def_verbose,
+                 log=_def_log):
+        """
+	Hierarchical block for RRC-filtered QPSK modulation.
+
+	The input is a byte stream (unsigned char) and the
+	output is the complex modulated signal at baseband.
+
+	@param samples_per_symbol: samples per symbol >= 2
+	@type samples_per_symbol: integer
+	@param excess_bw: Root-raised cosine filter excess bandwidth
+	@type excess_bw: float
+        @param gray_code: Tell modulator to Gray code the bits
+        @type gray_code: bool
+        @param verbose: Print information about modulator?
+        @type verbose: bool
+        @param debug: Print modualtion data to files?
+        @type debug: bool
+	"""
+
+	gr.hier_block2.__init__(self, "dqpsk2_mod",
+				gr.io_signature(1, 1, gr.sizeof_char),       # Input signature
+				gr.io_signature(1, 1, gr.sizeof_gr_complex)) # Output signature
+
+        self._samples_per_symbol = samples_per_symbol
+        self._excess_bw = excess_bw
+        self._gray_code = gray_code
+
+        if not isinstance(samples_per_symbol, int) or samples_per_symbol < 2:
+            raise TypeError, ("sbp must be an integer >= 2, is %d" % samples_per_symbol)
+
+	ntaps = 11 * samples_per_symbol
+ 
+        arity = pow(2,self.bits_per_symbol())
+
+        # turn bytes into k-bit vectors
+        self.bytes2chunks = \
+          gr.packed_to_unpacked_bb(self.bits_per_symbol(), gr.GR_MSB_FIRST)
+
+        if self._gray_code:
+            self.symbol_mapper = gr.map_bb(psk.binary_to_gray[arity])
+        else:
+            self.symbol_mapper = gr.map_bb(psk.binary_to_ungray[arity])
+            
+        self.diffenc = gr.diff_encoder_bb(arity)
+
+        rot = .707 + .707j
+        rotated_const = map(lambda pt: pt * rot, psk.constellation[arity])
+        self.chunks2symbols = gr.chunks_to_symbols_bc(rotated_const)
+
+        # pulse shaping filter
+	self.rrc_taps = gr.firdes.root_raised_cosine(
+	    self._samples_per_symbol, # gain  (sps since we're interpolating by sps)
+            self._samples_per_symbol, # sampling rate
+            1.0,		      # symbol rate
+            self._excess_bw,          # excess bandwidth (roll-off factor)
+            ntaps)
+
+	self.rrc_filter = gr.interp_fir_filter_ccf(self._samples_per_symbol, self.rrc_taps)
+
+        if verbose:
+            self._print_verbage()
+        
+        if log:
+            self._setup_logging()
+            
+	# Connect & Initialize base class
+        self.connect(self, self.bytes2chunks, self.symbol_mapper, self.diffenc,
+                     self.chunks2symbols, self.rrc_filter, self)
+
+    def samples_per_symbol(self):
+        return self._samples_per_symbol
+
+    def bits_per_symbol(self=None):   # staticmethod that's also callable on an instance
+        return 2
+    bits_per_symbol = staticmethod(bits_per_symbol)      # make it a static method.  RTFM
+
+    def _print_verbage(self):
+        print "\nModulator:"
+        print "bits per symbol:     %d" % self.bits_per_symbol()
+        print "Gray code:           %s" % self._gray_code
+        print "RRS roll-off factor: %f" % self._excess_bw
+
+    def _setup_logging(self):
+        print "Modulation logging turned on."
+        self.connect(self.bytes2chunks,
+                     gr.file_sink(gr.sizeof_char, "tx_bytes2chunks.dat"))
+        self.connect(self.symbol_mapper,
+                     gr.file_sink(gr.sizeof_char, "tx_graycoder.dat"))
+        self.connect(self.diffenc,
+                     gr.file_sink(gr.sizeof_char, "tx_diffenc.dat"))        
+        self.connect(self.chunks2symbols,
+                     gr.file_sink(gr.sizeof_gr_complex, "tx_chunks2symbols.dat"))
+        self.connect(self.rrc_filter,
+                     gr.file_sink(gr.sizeof_gr_complex, "tx_rrc_filter.dat"))
+
+    def add_options(parser):
+        """
+        Adds QPSK modulation-specific options to the standard parser
+        """
+        parser.add_option("", "--excess-bw", type="float", default=_def_excess_bw,
+                          help="set RRC excess bandwith factor [default=%default] (PSK)")
+        parser.add_option("", "--no-gray-code", dest="gray_code",
+                          action="store_false", default=_def_gray_code,
+                          help="disable gray coding on modulated bits (PSK)")
+    add_options=staticmethod(add_options)
+
+
+    def extract_kwargs_from_options(options):
+        """
+        Given command line options, create dictionary suitable for passing to __init__
+        """
+        return modulation_utils.extract_kwargs_from_options(dqpsk2_mod.__init__,
+                                                            ('self',), options)
+    extract_kwargs_from_options=staticmethod(extract_kwargs_from_options)
+
+
+# /////////////////////////////////////////////////////////////////////////////
+#                           DQPSK demodulator
+#
+# Differentially coherent detection of differentially encoded qpsk
+# /////////////////////////////////////////////////////////////////////////////
+
+class dqpsk2_demod(gr.hier_block2):
+
+    def __init__(self, 
+                 samples_per_symbol=_def_samples_per_symbol,
+                 excess_bw=_def_excess_bw,
+                 costas_alpha=_def_costas_alpha,
+                 timing_alpha=_def_timing_alpha,
+                 timing_max_dev=_def_timing_max_dev,
+                 gray_code=_def_gray_code,
+                 verbose=_def_verbose,
+                 log=_def_log):
+        """
+	Hierarchical block for RRC-filtered DQPSK demodulation
+
+	The input is the complex modulated signal at baseband.
+	The output is a stream of bits packed 1 bit per byte (LSB)
+
+	@param samples_per_symbol: samples per symbol >= 2
+	@type samples_per_symbol: float
+	@param excess_bw: Root-raised cosine filter excess bandwidth
+	@type excess_bw: float
+        @param costas_alpha: loop filter gain
+        @type costas_alphas: float
+        @param timing_alpha: timing loop alpha gain
+        @type timing_alpha: float
+        @param timing_max: timing loop maximum rate deviations
+        @type timing_max: float
+        @param gray_code: Tell modulator to Gray code the bits
+        @type gray_code: bool
+        @param verbose: Print information about modulator?
+        @type verbose: bool
+        @param debug: Print modualtion data to files?
+        @type debug: bool
+	"""
+
+	gr.hier_block2.__init__(self, "dqpsk2_demod",
+			        gr.io_signature(1, 1, gr.sizeof_gr_complex), # Input signature
+			        gr.io_signature(1, 1, gr.sizeof_char))       # Output signature
+
+        self._samples_per_symbol = samples_per_symbol
+        self._excess_bw = excess_bw
+        self._costas_alpha = costas_alpha
+        self._timing_alpha = timing_alpha
+        self._timing_beta = _def_timing_alpha
+        self._timing_max_dev=timing_max_dev
+        self._gray_code = gray_code
+
+        if samples_per_symbol < 2:
+            raise TypeError, "sbp must be >= 2, is %d" % samples_per_symbol
+
+        arity = pow(2,self.bits_per_symbol())
+ 
+        # Automatic gain control
+        self.agc = gr.agc2_cc(0.6e-1, 1e-3, 1, 1, 100)
+        #self.agc = gr.feedforward_agc_cc(16, 2.0)
+
+        self._costas_beta  = 0.25 * self._costas_alpha * self._costas_alpha
+        # Allow a frequency swing of +/- half of the sample rate
+        fmin = -0.5
+        fmax = 0.5
+
+        self.clock_recov = gr.costas_loop_cc(self._costas_alpha,
+                                             self._costas_beta,
+                                             fmax, fmin, arity)
+
+        # symbol clock recovery
+        if not self._timing_alpha:
+            self._timing_alpha = 2
+            self._timing_beta = 0.020
+            
+        # RRC data filter
+        nfilts = 32
+        ntaps = 11 * samples_per_symbol*nfilts
+        taps = gr.firdes.root_raised_cosine(nfilts, nfilts, 1.0/float(self._samples_per_symbol), self._excess_bw, ntaps)
+        self.time_recov = gr.pfb_clock_sync_ccf(self._samples_per_symbol,
+                                                self._timing_alpha,
+                                                taps, nfilts, nfilts/2, self._timing_max_dev)
+        self.time_recov.set_beta(self._timing_beta)
+        
+        # Perform Differential decoding on the constellation
+        self.diffdec = gr.diff_phasor_cc()
+        
+        # find closest constellation point
+        rot = 1
+        rotated_const = map(lambda pt: pt * rot, psk.constellation[arity])
+        self.slicer = gr.constellation_decoder_cb(rotated_const, range(arity))
+
+        if self._gray_code:
+            self.symbol_mapper = gr.map_bb(psk.gray_to_binary[arity])
+        else:
+            self.symbol_mapper = gr.map_bb(psk.ungray_to_binary[arity])
+        
+        # unpack the k bit vector into a stream of bits
+        self.unpack = gr.unpack_k_bits_bb(self.bits_per_symbol())
+
+        if verbose:
+            self._print_verbage()
+        
+        if log:
+            self._setup_logging()
+ 
+        # Connect
+        self.connect(self, self.agc, 
+                     self.clock_recov,
+                     self.time_recov,
+                     self.diffdec, self.slicer, self.symbol_mapper, self.unpack, self)
+
+    def samples_per_symbol(self):
+        return self._samples_per_symbol
+
+    def bits_per_symbol(self=None):   # staticmethod that's also callable on an instance
+        return 2
+    bits_per_symbol = staticmethod(bits_per_symbol)      # make it a static method.  RTFM
+
+    def _print_verbage(self):
+        print "\nDemodulator:"
+        print "bits per symbol:     %d"   % self.bits_per_symbol()
+        print "Gray code:           %s"   % self._gray_code
+        print "RRC roll-off factor: %.2f" % self._excess_bw
+        print "Costas Loop alpha:   %.2e" % self._costas_alpha
+        print "Costas Loop beta:    %.2e" % self._costas_beta
+        print "Timing alpha gain:   %.2f" % self._timing_alpha
+        print "Timing beta gain:    %.2f" % self._timing_beta
+        print "Timing max dev:      %.2f" % self._timing_max_dev
+
+    def _setup_logging(self):
+        print "Modulation logging turned on."
+        self.connect(self.pre_scaler,
+                     gr.file_sink(gr.sizeof_gr_complex, "rx_prescaler.dat"))
+        self.connect(self.agc,
+                     gr.file_sink(gr.sizeof_gr_complex, "rx_agc.dat"))
+        self.connect(self.rrc_filter,
+                     gr.file_sink(gr.sizeof_gr_complex, "rx_rrc_filter.dat"))
+        self.connect(self.clock_recov,
+                     gr.file_sink(gr.sizeof_gr_complex, "rx_clock_recov.dat"))
+        self.connect(self.time_recov,
+                     gr.file_sink(gr.sizeof_gr_complex, "rx_time_recov.dat"))
+        self.connect(self.diffdec,
+                     gr.file_sink(gr.sizeof_gr_complex, "rx_diffdec.dat"))        
+        self.connect(self.slicer,
+                     gr.file_sink(gr.sizeof_char, "rx_slicer.dat"))
+        self.connect(self.symbol_mapper,
+                     gr.file_sink(gr.sizeof_char, "rx_gray_decoder.dat"))
+        self.connect(self.unpack,
+                     gr.file_sink(gr.sizeof_char, "rx_unpack.dat"))
+
+    def add_options(parser):
+        """
+        Adds modulation-specific options to the standard parser
+        """
+        parser.add_option("", "--excess-bw", type="float", default=_def_excess_bw,
+                          help="set RRC excess bandwith factor [default=%default] (PSK)")
+        parser.add_option("", "--no-gray-code", dest="gray_code",
+                          action="store_false", default=_def_gray_code,
+                          help="disable gray coding on modulated bits (PSK)")
+        parser.add_option("", "--costas-alpha", type="float", default=_def_costas_alpha,
+                          help="set Costas loop alpha value [default=%default] (PSK)")
+        parser.add_option("", "--gain-alpha", type="float", default=_def_timing_alpha,
+                          help="set timing symbol sync loop gain alpha value [default=%default] (GMSK/PSK)")
+        parser.add_option("", "--gain-beta", type="float", default=_def_timing_beta,
+                          help="set timing symbol sync loop gain beta value [default=%default] (GMSK/PSK)")
+        parser.add_option("", "--timing-max-dev", type="float", default=_def_timing_max_dev,
+                          help="set timing symbol sync loop maximum deviation [default=%default] (GMSK/PSK)")
+    add_options=staticmethod(add_options)
+
+    def extract_kwargs_from_options(options):
+        """
+        Given command line options, create dictionary suitable for passing to __init__
+        """
+        return modulation_utils.extract_kwargs_from_options(
+            dqpsk2_demod.__init__, ('self',), options)
+    extract_kwargs_from_options=staticmethod(extract_kwargs_from_options)
+
+
+#
+# Add these to the mod/demod registry
+#
+modulation_utils.add_type_1_mod('dqpsk2', dqpsk2_mod)
+modulation_utils.add_type_1_demod('dqpsk2', dqpsk2_demod)