diff options
| author | eb <eb@221aa14e-8319-0410-a670-987f0aec2ac5> | 2006-09-27 05:14:03 +0000 |
|---|---|---|
| committer | eb <eb@221aa14e-8319-0410-a670-987f0aec2ac5> | 2006-09-27 05:14:03 +0000 |
| commit | f1c41f807cb29472d0924149e39d6ec8ad90e6a2 (patch) | |
| tree | 47e42f8cdfc83aaa3b706e06862c3efa4ba16745 /gnuradio-core/src/python/gnuradio/blksimpl/dbpsk.py | |
| parent | 04bb51ec4f1539c51c861b7fcad2ca8047a872a3 (diff) | |
Merged changes from eb/digital-wip into trunk.
This includes:
* renaming gnuradio-examples/python/gmsk2 to gnuradio-examples/python/digital
* refactoring the digital data tx and rx test code into benchmark_tx
and benchmark_rx. These accept a -m <modulation> argument.
<modulation> can currently be selected from gmsk, dbpsk, dqpsk
* Two new AGC blocks: gr_agc2: separate attack and delay rates;
gr_feedforward_agc: FIR-ish compressor. Normalizes to peak envelope.
* Working DBPSK mod/demod (works fine)
* Working DQPSK mod/demod (works, but still needs more work)
git-svn-id: http://gnuradio.org/svn/gnuradio/trunk@3662 221aa14e-8319-0410-a670-987f0aec2ac5
Diffstat (limited to 'gnuradio-core/src/python/gnuradio/blksimpl/dbpsk.py')
| -rw-r--r-- | gnuradio-core/src/python/gnuradio/blksimpl/dbpsk.py | 370 |
1 files changed, 370 insertions, 0 deletions
diff --git a/gnuradio-core/src/python/gnuradio/blksimpl/dbpsk.py b/gnuradio-core/src/python/gnuradio/blksimpl/dbpsk.py new file mode 100644 index 0000000000..20b940bf05 --- /dev/null +++ b/gnuradio-core/src/python/gnuradio/blksimpl/dbpsk.py @@ -0,0 +1,370 @@ +# +# 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. +# + +# See gnuradio-examples/python/gmsk2 for examples + +""" +differential BPSK modulation and demodulation. +""" + +from gnuradio import gr, gru, modulation_utils +from math import pi, sqrt +import psk +import cmath +import Numeric +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 = 0.05 +_def_gain_mu = 0.03 +_def_mu = 0.05 +_def_omega_relative_limit = 0.005 + + +# ///////////////////////////////////////////////////////////////////////////// +# DBPSK modulator +# ///////////////////////////////////////////////////////////////////////////// + +class dbpsk_mod(gr.hier_block): + + def __init__(self, fg, + 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 differential BPSK modulation. + + The input is a byte stream (unsigned char) and the + output is the complex modulated signal at baseband. + + @param fg: flow graph + @type fg: flow graph + @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 gray_code: Tell modulator to Gray code the bits + @type gray_code: bool + @param verbose: Print information about modulator? + @type verbose: bool + @param log: Log modulation data to files? + @type log: bool + """ + + self._fg = fg + self._samples_per_symbol = samples_per_symbol + self._excess_bw = excess_bw + self._gray_code = gray_code + + 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._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) + + self.chunks2symbols = gr.chunks_to_symbols_bc(psk.constellation[arity]) + + # 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 + fg.connect(self.bytes2chunks, self.symbol_mapper, self.diffenc, + self.chunks2symbols, self.rrc_filter) + + if verbose: + self._print_verbage() + + if log: + self._setup_logging() + + # Initialize base class + gr.hier_block.__init__(self, self._fg, self.bytes2chunks, self.rrc_filter) + + def samples_per_symbol(self): + return self._samples_per_symbol + + def bits_per_symbol(self=None): # static method that's also callable on an instance + return 1 + bits_per_symbol = staticmethod(bits_per_symbol) # make it a static method. RTFM + + def add_options(parser): + """ + Adds DBPSK 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]") + parser.add_option("", "--no-gray-code", dest="gray_code", + action="store_false", default=True, + 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(dbpsk_mod.__init__, + ('self', 'fg'), options) + extract_kwargs_from_options=staticmethod(extract_kwargs_from_options) + + + def _print_verbage(self): + 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 + + def _setup_logging(self): + print "Modulation logging turned on." + self._fg.connect(self.bytes2chunks, + gr.file_sink(gr.sizeof_char, "bytes2chunks.dat")) + self._fg.connect(self.symbol_mapper, + gr.file_sink(gr.sizeof_char, "graycoder.dat")) + self._fg.connect(self.diffenc, + gr.file_sink(gr.sizeof_char, "diffenc.dat")) + self._fg.connect(self.chunks2symbols, + gr.file_sink(gr.sizeof_gr_complex, "chunks2symbols.dat")) + self._fg.connect(self.rrc_filter, + gr.file_sink(gr.sizeof_gr_complex, "rrc_filter.dat")) + + +# ///////////////////////////////////////////////////////////////////////////// +# DBPSK demodulator +# +# Differentially coherent detection of differentially encoded BPSK +# ///////////////////////////////////////////////////////////////////////////// + +class dbpsk_demod(gr.hier_block): + + def __init__(self, fg, + samples_per_symbol=_def_samples_per_symbol, + excess_bw=_def_excess_bw, + costas_alpha=_def_costas_alpha, + gain_mu=_def_gain_mu, + mu=_def_mu, + omega_relative_limit=_def_omega_relative_limit, + gray_code=_def_gray_code, + verbose=_def_verbose, + log=_def_log): + """ + Hierarchical block for RRC-filtered differential BPSK demodulation + + The input is the complex modulated signal at baseband. + The output is a stream of bits packed 1 bit per byte (LSB) + + @param fg: flow graph + @type fg: flow graph + @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 gain_mu: for M&M block + @type gain_mu: float + @param mu: for M&M block + @type mu: float + @param omega_relative_limit: for M&M block + @type omega_relative_limit: 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 + """ + + self._fg = fg + self._samples_per_symbol = samples_per_symbol + self._excess_bw = excess_bw + self._costas_alpha = costas_alpha + self._gain_mu = gain_mu + self._mu = mu + self._omega_relative_limit = omega_relative_limit + self._gray_code = gray_code + + if samples_per_symbol < 2: + raise TypeError, "samples_per_symbol must be >= 2, is %r" % (samples_per_symbol,) + + arity = pow(2,self.bits_per_symbol()) + + # Automatic gain control + scale = (1.0/16384.0) + self.pre_scaler = gr.multiply_const_cc(scale) # scale the signal from full-range to +-1 + #self.agc = gr.agc2_cc(0.6e-1, 1e-3, 1, 1, 100) + self.agc = gr.feedforward_agc_cc(16, 1.0) + + + # Costas loop (carrier tracking) + # FIXME: need to decide how to handle this more generally; do we pull it from higher layer? + costas_order = 2 + beta = .25 * self._costas_alpha * self._costas_alpha + self.costas_loop = gr.costas_loop_cc(self._costas_alpha, beta, 0.002, -0.002, costas_order) + + # RRC data filter + ntaps = 11 * self._samples_per_symbol + self.rrc_taps = gr.firdes.root_raised_cosine( + 1.0, # gain + self._samples_per_symbol, # sampling rate + 1.0, # symbol rate + self._excess_bw, # excess bandwidth (roll-off factor) + ntaps) + + self.rrc_filter=gr.fir_filter_ccf(1, self.rrc_taps) + + # symbol clock recovery + omega = self._samples_per_symbol + gain_omega = .25 * self._gain_mu * self._gain_mu + self.clock_recovery=gr.clock_recovery_mm_cc(omega, gain_omega, + self._mu, self._gain_mu, + self._omega_relative_limit) + + # find closest constellation point + rot = 1 + rotated_const = map(lambda pt: pt * rot, psk.constellation[arity]) + #print "rotated_const =", rotated_const + + self.diffdec = gr.diff_phasor_cc() + #self.diffdec = gr.diff_decoder_bb(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 and Initialize base class + self._fg.connect(self.pre_scaler, self.agc, self.costas_loop, + self.rrc_filter, self.clock_recovery, self.diffdec, + self.slicer, self.symbol_mapper, self.unpack) + + gr.hier_block.__init__(self, self._fg, self.pre_scaler, self.unpack) + + 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 1 + bits_per_symbol = staticmethod(bits_per_symbol) # make it a static method. RTFM + + def _print_verbage(self): + 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 = %.5f" % self._costas_alpha + print "M&M symbol sync gain = %.5f" % self._gain_mu + print "M&M symbol sync mu = %.5f" % self._mu + print "M&M omega relative limit = %.5f" % self._omega_relative_limit + + def _setup_logging(self): + print "Modulation logging turned on." + self._fg.connect(self.pre_scaler, + gr.file_sink(gr.sizeof_gr_complex, "prescaler.dat")) + self._fg.connect(self.agc, + gr.file_sink(gr.sizeof_gr_complex, "agc.dat")) + self._fg.connect(self.costas_loop, + gr.file_sink(gr.sizeof_gr_complex, "costas_loop.dat")) + self._fg.connect((self.costas_loop,1), + gr.file_sink(gr.sizeof_gr_complex, "costas_error.dat")) + self._fg.connect(self.rrc_filter, + gr.file_sink(gr.sizeof_gr_complex, "rrc_filter.dat")) + self._fg.connect(self.clock_recovery, + gr.file_sink(gr.sizeof_gr_complex, "clock_recovery.dat")) + self._fg.connect((self.clock_recovery,1), + gr.file_sink(gr.sizeof_gr_complex, "clock_recovery_error.dat")) + self._fg.connect(self.diffdec, + gr.file_sink(gr.sizeof_gr_complex, "diffdec.dat")) + self._fg.connect(self.slicer, + gr.file_sink(gr.sizeof_char, "slicer.dat")) + self._fg.connect(self.gray_decoder, + gr.file_sink(gr.sizeof_char, "gray_decoder.dat")) + self._fg.connect(self.unpack, + gr.file_sink(gr.sizeof_char, "unpack.dat")) + + def add_options(parser): + """ + Adds DBPSK demodulation-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=None, + help="set Costas loop alpha value [default=%default] (PSK)") + parser.add_option("", "--gain-mu", type="float", default=_def_gain_mu, + help="set M&M symbol sync loop gain mu value [default=%default] (GMSK/PSK)") + parser.add_option("", "--mu", type="float", default=_def_mu, + help="set M&M symbol sync loop mu value [default=%default] (GMSK/PSK)") + parser.add_option("", "--omega-relative-limit", type="float", default=_def_omega_relative_limit, + help="M&M clock recovery omega relative limit [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( + dbpsk_demod.__init__, ('self', 'fg'), options) + extract_kwargs_from_options=staticmethod(extract_kwargs_from_options) + +# +# Add these to the mod/demod registry +# +modulation_utils.add_type_1_mod('dbpsk', dbpsk_mod) +modulation_utils.add_type_1_demod('dbpsk', dbpsk_demod) |