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Diffstat (limited to 'gr-digital/python/generic_mod_demod.py')
| -rw-r--r-- | gr-digital/python/generic_mod_demod.py | 395 |
1 files changed, 395 insertions, 0 deletions
diff --git a/gr-digital/python/generic_mod_demod.py b/gr-digital/python/generic_mod_demod.py new file mode 100644 index 000000000..4b1819ed7 --- /dev/null +++ b/gr-digital/python/generic_mod_demod.py @@ -0,0 +1,395 @@ +# +# Copyright 2005,2006,2007,2009,2011 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 + +""" +Generic modulation and demodulation. +""" + +from gnuradio import gr +from gnuradio.modulation_utils2 import extract_kwargs_from_options_for_class +from gnuradio.digital.utils import mod_codes + +# default values (used in __init__ and add_options) +_def_samples_per_symbol = 2 +_def_excess_bw = 0.35 +_def_verbose = False +_def_log = False + +# Frequency correction +_def_freq_alpha = 0.010 +# Symbol timing recovery +_def_timing_alpha = 0.100 +_def_timing_beta = 0.010 +_def_timing_max_dev = 1.5 +# Fine frequency / Phase correction +_def_phase_alpha = 0.1 +# Number of points in constellation +_def_constellation_points = 16 +# Whether differential coding is used. +_def_differential = True + +def add_common_options(parser): + """ + Sets options common to both modulator and demodulator. + """ + parser.add_option("-p", "--constellation-points", type="int", default=_def_constellation_points, + help="set the number of constellation points (must be a power of 2 (power of 4 for QAM) [default=%default]") + parser.add_option("", "--differential", action="store_true", dest="differential", default=True, + help="use differential encoding [default=%default]") + parser.add_option("", "--not-differential", action="store_false", dest="differential", + help="do not use differential encoding [default=%default]") + parser.add_option("", "--mod-code", type="choice", choices=mod_codes.codes, + default=mod_codes.NO_CODE, + help="Select modulation code from: %s [default=%%default]" + % (', '.join(mod_codes.codes),)) + parser.add_option("", "--excess-bw", type="float", default=_def_excess_bw, + help="set RRC excess bandwith factor [default=%default]") + + +# ///////////////////////////////////////////////////////////////////////////// +# Generic modulator +# ///////////////////////////////////////////////////////////////////////////// + +class generic_mod(gr.hier_block2): + + def __init__(self, constellation, + differential=_def_differential, + samples_per_symbol=_def_samples_per_symbol, + excess_bw=_def_excess_bw, + verbose=_def_verbose, + log=_def_log): + """ + Hierarchical block for RRC-filtered differential generic modulation. + + The input is a byte stream (unsigned char) and the + output is the complex modulated signal at baseband. + + @param constellation: determines the modulation type + @type constellation: gnuradio.gr.gr_constellation + @param samples_per_symbol: samples per baud >= 2 + @type samples_per_symbol: integer + @param excess_bw: Root-raised cosine filter excess bandwidth + @type excess_bw: float + @param verbose: Print information about modulator? + @type verbose: bool + @param log: Log modulation data to files? + @type log: bool + """ + + gr.hier_block2.__init__(self, "generic_mod", + gr.io_signature(1, 1, gr.sizeof_char), # Input signature + gr.io_signature(1, 1, gr.sizeof_gr_complex)) # Output signature + + self._constellation = constellation.base() + self._samples_per_symbol = samples_per_symbol + self._excess_bw = excess_bw + self._differential = differential + + if not isinstance(self._samples_per_symbol, int) or self._samples_per_symbol < 2: + raise TypeError, ("sbp must be an integer >= 2, is %d" % self._samples_per_symbol) + + ntaps = 11 * self._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._constellation.apply_pre_diff_code(): + self.symbol_mapper = gr.map_bb(self._constellation.pre_diff_code()) + + if differential: + self.diffenc = gr.diff_encoder_bb(arity) + + self.chunks2symbols = gr.chunks_to_symbols_bc(self._constellation.points()) + + # pulse shaping filter + self.rrc_taps = gr.firdes.root_raised_cosine( + self._samples_per_symbol, # gain (samples_per_symbol since we're + # interpolating by samples_per_symbol) + 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) + + # Connect + blocks = [self, self.bytes2chunks] + if self._constellation.apply_pre_diff_code(): + blocks.append(self.symbol_mapper) + if differential: + blocks.append(self.diffenc) + blocks += [self.chunks2symbols, self.rrc_filter, self] + self.connect(*blocks) + + if verbose: + self._print_verbage() + + if log: + self._setup_logging() + + + def samples_per_symbol(self): + return self._samples_per_symbol + + def bits_per_symbol(self): # static method that's also callable on an instance + return self._constellation.bits_per_symbol() + + def add_options(parser): + """ + Adds generic modulation options to the standard parser + """ + add_common_options(parser) + add_options=staticmethod(add_options) + + def extract_kwargs_from_options(cls, options): + """ + Given command line options, create dictionary suitable for passing to __init__ + """ + return extract_kwargs_from_options_for_class(cls, options) + extract_kwargs_from_options=classmethod(extract_kwargs_from_options) + + + def _print_verbage(self): + print "\nModulator:" + print "bits per symbol: %d" % self.bits_per_symbol() + print "RRC roll-off factor: %.2f" % 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")) + if self._constellation.apply_pre_diff_code(): + self.connect(self.symbol_mapper, + gr.file_sink(gr.sizeof_char, "tx_symbol_mapper.dat")) + if self._differential: + 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")) + + +# ///////////////////////////////////////////////////////////////////////////// +# Generic demodulator +# +# Differentially coherent detection of differentially encoded generically +# modulated signal. +# ///////////////////////////////////////////////////////////////////////////// + +class generic_demod(gr.hier_block2): + + def __init__(self, constellation, + samples_per_symbol=_def_samples_per_symbol, + differential=_def_differential, + excess_bw=_def_excess_bw, + freq_alpha=_def_freq_alpha, + timing_alpha=_def_timing_alpha, + timing_max_dev=_def_timing_max_dev, + phase_alpha=_def_phase_alpha, + verbose=_def_verbose, + log=_def_log): + """ + Hierarchical block for RRC-filtered differential generic demodulation. + + The input is the complex modulated signal at baseband. + The output is a stream of bits packed 1 bit per byte (LSB) + + @param constellation: determines the modulation type + @type constellation: gnuradio.gr.gr_constellation + @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 freq_alpha: loop filter gain for frequency recovery + @type freq_alpha: float + @param timing_alpha: loop alpha gain for timing recovery + @type timing_alpha: float + @param timing_max_dev: timing loop maximum rate deviations + @type timing_max_dev: float + @param phase_alpha: loop filter gain in phase loop + @type phase_alphas: float + @param verbose: Print information about modulator? + @type verbose: bool + @param debug: Print modualtion data to files? + @type debug: bool + """ + + gr.hier_block2.__init__(self, "generic_demod", + gr.io_signature(1, 1, gr.sizeof_gr_complex), # Input signature + gr.io_signature(1, 1, gr.sizeof_char)) # Output signature + + self._constellation = constellation.base() + self._samples_per_symbol = samples_per_symbol + self._excess_bw = excess_bw + self._phase_alpha = phase_alpha + self._freq_alpha = freq_alpha + self._freq_beta = 0.10*self._freq_alpha + self._timing_alpha = timing_alpha + self._timing_beta = _def_timing_beta + self._timing_max_dev=timing_max_dev + self._differential = differential + + if not isinstance(self._samples_per_symbol, int) or self._samples_per_symbol < 2: + raise TypeError, ("sbp must be an integer >= 2, is %d" % self._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) + + # Frequency correction + self.freq_recov = gr.fll_band_edge_cc(self._samples_per_symbol, self._excess_bw, + 11*int(self._samples_per_symbol), + self._freq_alpha, self._freq_beta) + + # symbol timing recovery with RRC data filter + nfilts = 32 + ntaps = 11 * int(self._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) + + #self._phase_beta = 0.25 * self._phase_alpha * self._phase_alpha + self._phase_beta = 0.25 * self._phase_alpha * self._phase_alpha + fmin = -0.25 + fmax = 0.25 + + self.receiver = gr.constellation_receiver_cb( + self._constellation, + self._phase_alpha, self._phase_beta, + fmin, fmax) + + # Do differential decoding based on phase change of symbols + if differential: + self.diffdec = gr.diff_decoder_bb(arity) + + if self._constellation.apply_pre_diff_code(): + self.symbol_mapper = gr.map_bb( + mod_codes.invert_code(self._constellation.pre_diff_code())) + + # 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 and Initialize base class + blocks = [self, self.agc, self.freq_recov, self.time_recov, self.receiver] + if differential: + blocks.append(self.diffdec) + if self._constellation.apply_pre_diff_code(): + blocks.append(self.symbol_mapper) + blocks += [self.unpack, self] + self.connect(*blocks) + + def samples_per_symbol(self): + return self._samples_per_symbol + + def bits_per_symbol(self): # staticmethod that's also callable on an instance + return self._constellation.bits_per_symbol() + + def _print_verbage(self): + print "\nDemodulator:" + print "bits per symbol: %d" % self.bits_per_symbol() + print "RRC roll-off factor: %.2f" % self._excess_bw + print "FLL gain: %.2e" % self._freq_alpha + print "Timing alpha gain: %.2e" % self._timing_alpha + print "Timing beta gain: %.2e" % self._timing_beta + print "Timing max dev: %.2f" % self._timing_max_dev + print "Phase track alpha: %.2e" % self._phase_alpha + print "Phase track beta: %.2e" % self._phase_beta + + def _setup_logging(self): + print "Modulation logging turned on." + self.connect(self.agc, + gr.file_sink(gr.sizeof_gr_complex, "rx_agc.dat")) + self.connect((self.freq_recov, 0), + gr.file_sink(gr.sizeof_gr_complex, "rx_freq_recov.dat")) + self.connect((self.freq_recov, 1), + gr.file_sink(gr.sizeof_float, "rx_freq_recov_freq.dat")) + self.connect((self.freq_recov, 2), + gr.file_sink(gr.sizeof_float, "rx_freq_recov_phase.dat")) + self.connect((self.freq_recov, 3), + gr.file_sink(gr.sizeof_gr_complex, "rx_freq_recov_error.dat")) + self.connect((self.time_recov, 0), + gr.file_sink(gr.sizeof_gr_complex, "rx_time_recov.dat")) + self.connect((self.time_recov, 1), + gr.file_sink(gr.sizeof_float, "rx_time_recov_error.dat")) + self.connect((self.time_recov, 2), + gr.file_sink(gr.sizeof_float, "rx_time_recov_rate.dat")) + self.connect((self.time_recov, 3), + gr.file_sink(gr.sizeof_float, "rx_time_recov_phase.dat")) + self.connect((self.receiver, 0), + gr.file_sink(gr.sizeof_char, "rx_receiver.dat")) + self.connect((self.receiver, 1), + gr.file_sink(gr.sizeof_float, "rx_receiver_error.dat")) + self.connect((self.receiver, 2), + gr.file_sink(gr.sizeof_float, "rx_receiver_phase.dat")) + self.connect((self.receiver, 3), + gr.file_sink(gr.sizeof_float, "rx_receiver_freq.dat")) + if self._differential: + self.connect(self.diffdec, + gr.file_sink(gr.sizeof_char, "rx_diffdec.dat")) + if self._constellation.apply_pre_diff_code(): + self.connect(self.symbol_mapper, + gr.file_sink(gr.sizeof_char, "rx_symbol_mapper.dat")) + self.connect(self.unpack, + gr.file_sink(gr.sizeof_char, "rx_unpack.dat")) + + def add_options(parser): + """ + Adds generic demodulation options to the standard parser + """ + # Add options shared with modulator. + add_common_options(parser) + # Add options specific to demodulator. + parser.add_option("", "--freq-alpha", type="float", default=_def_freq_alpha, + help="set frequency lock loop alpha gain value [default=%default]") + parser.add_option("", "--phase-alpha", type="float", default=_def_phase_alpha, + help="set phase tracking loop alpha value [default=%default]") + parser.add_option("", "--timing-alpha", type="float", default=_def_timing_alpha, + help="set timing symbol sync loop gain alpha value [default=%default]") + parser.add_option("", "--timing-beta", type="float", default=_def_timing_beta, + help="set timing symbol sync loop gain beta value [default=%default]") + parser.add_option("", "--timing-max-dev", type="float", default=_def_timing_max_dev, + help="set timing symbol sync loop maximum deviation [default=%default]") + add_options=staticmethod(add_options) + + def extract_kwargs_from_options(cls, options): + """ + Given command line options, create dictionary suitable for passing to __init__ + """ + return extract_kwargs_from_options_for_class(cls, options) + extract_kwargs_from_options=classmethod(extract_kwargs_from_options) + |