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   1 #
   2 # Copyright 2005,2006 Free Software Foundation, Inc.
   3 #
   4 # This file is part of GNU Radio
   5 #
   6 # GNU Radio is free software; you can redistribute it and/or modify
   7 # it under the terms of the GNU General Public License as published by
   8 # the Free Software Foundation; either version 2, or (at your option)
   9 # any later version.
  10 #
  11 # GNU Radio is distributed in the hope that it will be useful,
  12 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 # GNU General Public License for more details.
  15 #
  16 # You should have received a copy of the GNU General Public License
  17 # along with GNU Radio; see the file COPYING.  If not, write to
  18 # the Free Software Foundation, Inc., 51 Franklin Street,
  19 # Boston, MA 02110-1301, USA.
  20 #
  21
  22 # See gnuradio-examples/python/digital for examples
  23
  24 """
  25 differential 8PSK modulation and demodulation.
  26 """
  27
  28 from gnuradio import gr, gru, modulation_utils
  29 from math import pi, sqrt
  30 import psk
  31 import cmath
  32 import Numeric
  33 from pprint import pprint
  34
  35 # default values (used in __init__ and add_options)
  36 _def_samples_per_symbol = 3
  37 _def_excess_bw = 0.35
  38 _def_gray_code = True
  39 _def_verbose = False
  40 _def_log = False
  41
  42 _def_costas_alpha = 0.01
  43 _def_gain_mu = 0.05
  44 _def_mu = 0.5
  45 _def_omega_relative_limit = 0.005
  46
  47
  48 # /////////////////////////////////////////////////////////////////////////////
  49 #                           DQPSK modulator
  50 # /////////////////////////////////////////////////////////////////////////////
  51
  52 class d8psk_mod(gr.hier_block2):
  53
  54     def __init__(self,
  55                  samples_per_symbol=_def_samples_per_symbol,
  56                  excess_bw=_def_excess_bw,
  57                  gray_code=_def_gray_code,
  58                  verbose=_def_verbose,
  59                  log=_def_log):
  60         """
  61         Hierarchical block for RRC-filtered QPSK modulation.
  62
  63         The input is a byte stream (unsigned char) and the
  64         output is the complex modulated signal at baseband.
  65
  66         @param samples_per_symbol: samples per symbol >= 2
  67         @type samples_per_symbol: integer
  68         @param excess_bw: Root-raised cosine filter excess bandwidth
  69         @type excess_bw: float
  70         @param gray_code: Tell modulator to Gray code the bits
  71         @type gray_code: bool
  72         @param verbose: Print information about modulator?
  73         @type verbose: bool
  74         @param debug: Print modualtion data to files?
  75         @type debug: bool
  76         """
  77
  78         gr.hier_block2.__init__(self, "d8psk_mod",
  79                                 gr.io_signature(1,1,gr.sizeof_char),       # Input signature
  80                                 gr.io_signature(1,1,gr.sizeof_gr_complex)) # Output signature
  81
  82         self._samples_per_symbol = samples_per_symbol
  83         self._excess_bw = excess_bw
  84         self._gray_code = gray_code
  85
  86         if not isinstance(samples_per_symbol, int) or samples_per_symbol < 2:
  87             raise TypeError, ("sbp must be an integer >= 2, is %d" % samples_per_symbol)
  88
  89         ntaps = 11 * samples_per_symbol
  90
  91         arity = pow(2,self.bits_per_symbol())
  92
  93         # turn bytes into k-bit vectors
  94         self.bytes2chunks = \
  95           gr.packed_to_unpacked_bb(self.bits_per_symbol(), gr.GR_MSB_FIRST)
  96
  97         if self._gray_code:
  98             self.symbol_mapper = gr.map_bb(psk.binary_to_gray[arity])
  99         else:
 100             self.symbol_mapper = gr.map_bb(psk.binary_to_ungray[arity])
 101
 102         self.diffenc = gr.diff_encoder_bb(arity)
 103
 104         rot = 1
 105         rotated_const = map(lambda pt: pt * rot, psk.constellation[arity])
 106         self.chunks2symbols = gr.chunks_to_symbols_bc(rotated_const)
 107
 108         # pulse shaping filter
 109         self.rrc_taps = gr.firdes.root_raised_cosine(
 110             self._samples_per_symbol, # gain  (sps since we're interpolating by sps)
 111             self._samples_per_symbol, # sampling rate
 112             1.0,                      # symbol rate
 113             self._excess_bw,          # excess bandwidth (roll-off factor)
 114             ntaps)
 115
 116         self.rrc_filter = gr.interp_fir_filter_ccf(self._samples_per_symbol, self.rrc_taps)
 117
 118         # Define components from objects
 119         self.define_component("bytes2chunks", self.bytes2chunks)
 120         self.define_component("symbol_mapper", self.symbol_mapper)
 121 #        self.define_component("diffenc", self.diffenc)
 122         self.define_component("chunks2symbols", self.chunks2symbols)
 123         self.define_component("rrc_filter", self.rrc_filter)
 124
 125         # Connect components
 126         self.connect("self", 0, "bytes2chunks", 0)
 127         self.connect("bytes2chunks", 0, "symbol_mapper", 0)
 128 #        self.connect("symbol_mapper", 0, "diffenc", 0)
 129 #        self.connect("diffenc", 0, "chunks2symbols", 0)
 130         self.connect("symbol_mapper", 0, "chunks2symbols", 0)
 131         self.connect("chunks2symbols", 0, "rrc_filter", 0)
 132         self.connect("rrc_filter", 0, "self", 0)
 133
 134         if verbose:
 135             self._print_verbage()
 136
 137         if log:
 138             self._setup_logging()
 139
 140
 141     def samples_per_symbol(self):
 142         return self._samples_per_symbol
 143
 144     def bits_per_symbol(self=None):   # staticmethod that's also callable on an instance
 145         return 3
 146     bits_per_symbol = staticmethod(bits_per_symbol)      # make it a static method.  RTFM
 147
 148     def _print_verbage(self):
 149         print "\nModulator:"
 150         print "bits per symbol = %d" % self.bits_per_symbol()
 151         print "Gray code = %s" % self._gray_code
 152         print "RS roll-off factor = %f" % self._excess_bw
 153
 154     def _setup_logging(self):
 155         print "Modulation logging turned on."
 156         self.define_component("bytes2chunks_dat", gr.file_sink(gr.sizeof_char, "tx_bytes2chunks.dat"))
 157         self.define_component("symbol_mapper_dat", gr.file_sink(gr.sizeof_char, "tx_symbol_mapper.dat"))
 158 #        self.define_component("diffenc_dat", gr.file_sink(gr.sizeof_char, "tx_diffenc.dat"))
 159         self.define_component("chunks2symbols_dat", gr.file_sink(gr.sizeof_gr_complex, "tx_chunks2symbols.dat"))
 160         self.define_component("rrc_filter_dat", gr.file_sink(gr.sizeof_gr_complex, "tx_rrc_filter.dat"))
 161
 162         self.connect("bytes2chunks", 0, "bytes2chunks_dat", 0)
 163         self.connect("symbol_mapper", 0, "symbol_mapper_dat", 0)
 164 #        self.connect("diffenc", 0, "diffenc_dat", 0)
 165         self.connect("chunks2symbols", 0, "chunks2symbols_dat", 0)
 166         self.connect("rrc_filter", 0, "rrc_filter_dat", 0)
 167
 168     def add_options(parser):
 169         """
 170         Adds 8PSK modulation-specific options to the standard parser
 171         """
 172         parser.add_option("", "--excess-bw", type="float", default=_def_excess_bw,
 173                           help="set RRC excess bandwith factor [default=%default] (PSK)")
 174         parser.add_option("", "--no-gray-code", dest="gray_code",
 175                           action="store_false", default=_def_gray_code,
 176                           help="disable gray coding on modulated bits (PSK)")
 177     add_options=staticmethod(add_options)
 178
 179
 180     def extract_kwargs_from_options(options):
 181         """
 182         Given command line options, create dictionary suitable for passing to __init__
 183         """
 184         return modulation_utils.extract_kwargs_from_options(d8psk_mod.__init__,
 185                                                             ('self', 'fg'), options)
 186     extract_kwargs_from_options=staticmethod(extract_kwargs_from_options)
 187
 188
 189 # /////////////////////////////////////////////////////////////////////////////
 190 #                           D8PSK demodulator
 191 #
 192 # Differentially coherent detection of differentially encoded 8psk
 193 # /////////////////////////////////////////////////////////////////////////////
 194
 195 WITH_SYNC = False
 196 class d8psk_demod(gr.hier_block2):
 197
 198     def __init__(self,
 199                  samples_per_symbol=_def_samples_per_symbol,
 200                  excess_bw=_def_excess_bw,
 201                  costas_alpha=_def_costas_alpha,
 202                  gain_mu=_def_gain_mu,
 203                  mu=_def_mu,
 204                  omega_relative_limit=_def_omega_relative_limit,
 205                  gray_code=_def_gray_code,
 206                  verbose=_def_verbose,
 207                  log=_def_log):
 208         """
 209         Hierarchical block for RRC-filtered DQPSK demodulation
 210
 211         The input is the complex modulated signal at baseband.
 212         The output is a stream of bits packed 1 bit per byte (LSB)
 213
 214         @param samples_per_symbol: samples per symbol >= 2
 215         @type samples_per_symbol: float
 216         @param excess_bw: Root-raised cosine filter excess bandwidth
 217         @type excess_bw: float
 218         @param costas_alpha: loop filter gain
 219         @type costas_alphas: float
 220         @param gain_mu: for M&M block
 221         @type gain_mu: float
 222         @param mu: for M&M block
 223         @type mu: float
 224         @param omega_relative_limit: for M&M block
 225         @type omega_relative_limit: float
 226         @param gray_code: Tell modulator to Gray code the bits
 227         @type gray_code: bool
 228         @param verbose: Print information about modulator?
 229         @type verbose: bool
 230         @param debug: Print modualtion data to files?
 231         @type debug: bool
 232         """
 233
 234         gr.hier_block2.__init__(self, "d8psk_demod",
 235                                 gr.io_signature(1,1,gr.sizeof_gr_complex), # Input signature
 236                                 gr.io_signature(1,1,gr.sizeof_char))       # Output signature
 237
 238         self._samples_per_symbol = samples_per_symbol
 239         self._excess_bw = excess_bw
 240         self._costas_alpha = costas_alpha
 241         self._mm_gain_mu = gain_mu
 242         self._mm_mu = mu
 243         self._mm_omega_relative_limit = omega_relative_limit
 244         self._gray_code = gray_code
 245
 246         if samples_per_symbol < 2:
 247             raise TypeError, "sbp must be >= 2, is %d" % samples_per_symbol
 248
 249         arity = pow(2,self.bits_per_symbol())
 250
 251         # Automatic gain control
 252         scale = (1.0/16384.0)
 253         self.pre_scaler = gr.multiply_const_cc(scale)   # scale the signal from full-range to +-1
 254         #self.agc = gr.agc2_cc(0.6e-1, 1e-3, 1, 1, 100)
 255         self.agc = gr.feedforward_agc_cc(16, 1.0)
 256
 257         # RRC data filter
 258         ntaps = 11 * samples_per_symbol
 259         self.rrc_taps = gr.firdes.root_raised_cosine(
 260             1.0,                      # gain
 261             self._samples_per_symbol, # sampling rate
 262             1.0,                      # symbol rate
 263             self._excess_bw,          # excess bandwidth (roll-off factor)
 264             ntaps)
 265         self.rrc_filter=gr.interp_fir_filter_ccf(1, self.rrc_taps)
 266
 267         # symbol clock recovery
 268         self._mm_omega = self._samples_per_symbol
 269         self._mm_gain_omega = .25 * self._mm_gain_mu * self._mm_gain_mu
 270         self._costas_beta  = 0.25 * self._costas_alpha * self._costas_alpha
 271         fmin = -0.05
 272         fmax = 0.05
 273
 274         self.receiver=gr.mpsk_receiver_cc(arity, 0,
 275                                           self._costas_alpha, self._costas_beta,
 276                                           fmin, fmax,
 277                                           self._mm_mu, self._mm_gain_mu,
 278                                           self._mm_omega, self._mm_gain_omega,
 279                                           self._mm_omega_relative_limit)
 280
 281         #self.diffdec = gr.diff_decoder_bb(arity)
 282
 283         # find closest constellation point
 284         rot = 1
 285         rotated_const = map(lambda pt: pt * rot, psk.constellation[arity])
 286         self.slicer = gr.constellation_decoder_cb(rotated_const, range(arity))
 287
 288         if self._gray_code:
 289             self.symbol_mapper = gr.map_bb(psk.gray_to_binary[arity])
 290         else:
 291             self.symbol_mapper = gr.map_bb(psk.ungray_to_binary[arity])
 292
 293
 294         # unpack the k bit vector into a stream of bits
 295         self.unpack = gr.unpack_k_bits_bb(self.bits_per_symbol())
 296
 297
 298         # Define components
 299         self.define_component("pre_scaler", self.pre_scaler)
 300         self.define_component("agc", self.agc)
 301         self.define_component("rrc_filter", self.rrc_filter)
 302         self.define_component("receiver", self.receiver)
 303         self.define_component("slicer", self.slicer)
 304         #self.define_component("diffdec", self.diffdec)
 305         self.define_component("symbol_mapper", self.symbol_mapper)
 306         self.define_component("unpack", self.unpack)
 307
 308         # Connect and Initialize base class
 309         self.connect("self", 0, "pre_scaler", 0)
 310         self.connect("pre_scaler", 0, "agc", 0)
 311         self.connect("agc", 0, "rrc_filter", 0)
 312         self.connect("rrc_filter", 0, "receiver", 0)
 313         self.connect("receiver", 0, "slicer", 0)
 314         #self.connect("slicer", 0, "diffdec", 0)
 315         #self.connect("diffdec", 0, "symbol_mapper", 0)
 316         self.connect("slicer", 0, "symbol_mapper", 0)
 317         self.connect("symbol_mapper", 0, "unpack", 0)
 318         self.connect("unpack", 0, "self", 0)
 319
 320         if verbose:
 321             self._print_verbage()
 322
 323         if log:
 324             self._setup_logging()
 325
 326
 327     def samples_per_symbol(self):
 328         return self._samples_per_symbol
 329
 330     def bits_per_symbol(self=None):   # staticmethod that's also callable on an instance
 331         return 3
 332     bits_per_symbol = staticmethod(bits_per_symbol)      # make it a static method.  RTFM
 333
 334     def _print_verbage(self):
 335         print "\nDemodulator:"
 336         print "bits per symbol:     %d"   % self.bits_per_symbol()
 337         print "Gray code:           %s"   % self._gray_code
 338         print "RRC roll-off factor: %.2f" % self._excess_bw
 339         print "Costas Loop alpha:   %.2e" % self._costas_alpha
 340         print "Costas Loop beta:    %.2e" % self._costas_beta
 341         print "M&M mu:              %.2f" % self._mm_mu
 342         print "M&M mu gain:         %.2e" % self._mm_gain_mu
 343         print "M&M omega:           %.2f" % self._mm_omega
 344         print "M&M omega gain:      %.2e" % self._mm_gain_omega
 345         print "M&M omega limit:     %.2f" % self._mm_omega_relative_limit
 346
 347
 348     def _setup_logging(self):
 349         print "Demodulation logging turned on."
 350         self.define_component("prescaler_dat",
 351                               gr.file_sink(gr.sizeof_gr_complex, "rx_prescaler.dat"))
 352         self.define_component("agc_dat",
 353                               gr.file_sink(gr.sizeof_gr_complex, "rx_agc.dat"))
 354         self.define_component("rrc_filter_dat",
 355                               gr.file_sink(gr.sizeof_gr_complex, "rx_rrc_filter.dat"))
 356         self.define_component("receiver_dat",
 357                               gr.file_sink(gr.sizeof_gr_complex, "rx_receiver.dat"))
 358         self.define_component("slicer_dat",
 359                               gr.file_sink(gr.sizeof_char, "rx_slicer.dat"))
 360 #        self.define_component("diffdec_dat",
 361 #                              gr.file_sink(gr.sizeof_char, "rx_diffdec.dat"))
 362         self.define_component("symbol_mapper_dat",
 363                               gr.file_sink(gr.sizeof_char, "rx_symbol_mapper.dat"))
 364         self.define_component("unpack_dat",
 365                               gr.file_sink(gr.sizeof_char, "rx_unpack.dat"))
 366
 367         self.connect("pre_scaler", 0, "prescaler_dat", 0)
 368         self.connect("agc", 0, "agc_dat", 0)
 369         self.connect("rrc_filter", 0, "rrc_filter_dat", 0)
 370         self.connect("receiver", 0, "receiver_dat", 0)
 371         self.connect("slicer", 0, "slicer_dat", 0)
 372 #        self.connect("diffdec", 0, "diffdec_dat", 0)
 373         self.connect("symbol_mapper", 0, "symbol_mapper_dat", 0)
 374         self.connect("unpack", 0, "unpack_dat", 0)
 375
 376     def add_options(parser):
 377         """
 378         Adds modulation-specific options to the standard parser
 379         """
 380         parser.add_option("", "--excess-bw", type="float", default=_def_excess_bw,
 381                           help="set RRC excess bandwith factor [default=%default] (PSK)")
 382         parser.add_option("", "--no-gray-code", dest="gray_code",
 383                           action="store_false", default=_def_gray_code,
 384                           help="disable gray coding on modulated bits (PSK)")
 385         parser.add_option("", "--costas-alpha", type="float", default=None,
 386                           help="set Costas loop alpha value [default=%default] (PSK)")
 387         parser.add_option("", "--gain-mu", type="float", default=_def_gain_mu,
 388                           help="set M&M symbol sync loop gain mu value [default=%default] (PSK)")
 389         parser.add_option("", "--mu", type="float", default=_def_mu,
 390                           help="set M&M symbol sync loop mu value [default=%default] (PSK)")
 391     add_options=staticmethod(add_options)
 392
 393     def extract_kwargs_from_options(options):
 394         """
 395         Given command line options, create dictionary suitable for passing to __init__
 396         """
 397         return modulation_utils.extract_kwargs_from_options(
 398             d8psk_demod.__init__, ('self', 'fg'), options)
 399     extract_kwargs_from_options=staticmethod(extract_kwargs_from_options)
 400
 401
 402 #
 403 # Add these to the mod/demod registry
 404 #
 405 # NOT READY TO BE USED YET -- ENABLE AT YOUR OWN RISK
 406 #modulation_utils.add_type_1_mod('d8psk', d8psk_mod)
 407 #modulation_utils.add_type_1_demod('d8psk', d8psk_demod)