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Diffstat (limited to 'gr-digital/examples/narrowband/digital_bert_rx.py')
| -rwxr-xr-x | gr-digital/examples/narrowband/digital_bert_rx.py | 209 |
1 files changed, 209 insertions, 0 deletions
diff --git a/gr-digital/examples/narrowband/digital_bert_rx.py b/gr-digital/examples/narrowband/digital_bert_rx.py new file mode 100755 index 000000000..9878f55e1 --- /dev/null +++ b/gr-digital/examples/narrowband/digital_bert_rx.py @@ -0,0 +1,209 @@ +#!/usr/bin/env python +# +# Copyright 2008,2011 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. +# + +from gnuradio import gr, eng_notation +from optparse import OptionParser +from gnuradio.eng_option import eng_option +import gnuradio.gr.gr_threading as _threading +import sys, time, math + +from gnuradio import digital + +# from current dir +from uhd_interface import uhd_receiver + +n2s = eng_notation.num_to_str + +class status_thread(_threading.Thread): + def __init__(self, tb): + _threading.Thread.__init__(self) + self.setDaemon(1) + self.tb = tb + self.done = False + self.start() + + def run(self): + while not self.done: + print "Freq. Offset: {0:5.0f} Hz Timing Offset: {1:10.1f} ppm Estimated SNR: {2:4.1f} dB BER: {3:g}".format( + tb.frequency_offset(), tb.timing_offset()*1e6, tb.snr(), tb.ber()) + try: + time.sleep(1.0) + except KeyboardInterrupt: + self.done = True + + + +class bert_receiver(gr.hier_block2): + def __init__(self, bitrate, + constellation, samples_per_symbol, + differential, excess_bw, gray_coded, + freq_bw, timing_bw, phase_bw, + verbose, log): + + gr.hier_block2.__init__(self, "bert_receive", + gr.io_signature(1, 1, gr.sizeof_gr_complex), # Input signature + gr.io_signature(0, 0, 0)) # Output signature + + self._bitrate = bitrate + + self._demod = digital.generic_demod(constellation, samples_per_symbol, + differential, excess_bw, gray_coded, + freq_bw, timing_bw, phase_bw, + verbose, log) + + self._symbol_rate = self._bitrate * self._demod.bits_per_symbol() + self._sample_rate = self._symbol_rate * samples_per_symbol + + # Add an SNR probe on the demodulated constellation + self._snr_probe = gr.probe_mpsk_snr_c(10.0/self._symbol_rate) + self.connect(self._demod.time_recov, self._snr_probe) + + # Descramble BERT sequence. A channel error will create 3 incorrect bits + self._descrambler = gr.descrambler_bb(0x8A, 0x7F, 7) # CCSDS 7-bit descrambler + + # Measure BER by the density of 0s in the stream + self._ber = gr.probe_density_b(1.0/self._symbol_rate) + + self.connect(self, self._demod, self._descrambler, self._ber) + + def frequency_offset(self): + return self._demod.freq_recov.get_frequency()*self._sample_rate/(2*math.pi) + + def timing_offset(self): + return self._demod.time_recov.get_clock_rate() + + def snr(self): + return self._snr_probe.snr() + + def ber(self): + return (1.0-self._ber.density())/3.0 + + + +class rx_psk_block(gr.top_block): + def __init__(self, demod, options): + + gr.top_block.__init__(self, "rx_mpsk") + + self._demodulator_class = demod + + # Get demod_kwargs + demod_kwargs = self._demodulator_class.extract_kwargs_from_options(options) + + # demodulator + self._demodulator = self._demodulator_class(**demod_kwargs) + + if(options.rx_freq is not None): + self._source = uhd_receiver(options.address, options.bitrate, + options.samples_per_symbol, + options.rx_freq, options.rx_gain, + options.antenna, options.verbose) + options.samples_per_symbol = self._source._sps + + elif(options.from_file is not None): + self._source = gr.file_source(gr.sizeof_gr_complex, options.from_file) + else: + self._source = gr.null_source(gr.sizeof_gr_complex) + + # Create the BERT receiver + self._receiver = bert_receiver(options.bitrate, + self._demodulator._constellation, + options.samples_per_symbol, + options.differential, + options.excess_bw, + gray_coded=True, + freq_bw=options.freq_bw, + timing_bw=options.timing_bw, + phase_bw=options.phase_bw, + verbose=options.verbose, + log=options.log) + + self.connect(self._source, self._receiver) + + def snr(self): + return self._receiver.snr() + + def mag(self): + return self._receiver.signal_mean() + + def var(self): + return self._receiver.noise_variance() + + def ber(self): + return self._receiver.ber() + + def frequency_offset(self): + return self._receiver.frequency_offset() + + def timing_offset(self): + return self._receiver.timing_offset() + + +def get_options(demods): + parser = OptionParser(option_class=eng_option, conflict_handler="resolve") + parser.add_option("","--from-file", default=None, + help="input file of samples to demod") + parser.add_option("-m", "--modulation", type="choice", choices=demods.keys(), + default='psk', + help="Select modulation from: %s [default=%%default]" + % (', '.join(demods.keys()),)) + parser.add_option("-r", "--bitrate", type="eng_float", default=250e3, + help="Select modulation bit rate (default=%default)") + parser.add_option("-S", "--samples-per-symbol", type="float", default=2, + help="set samples/symbol [default=%default]") + if not parser.has_option("--verbose"): + parser.add_option("-v", "--verbose", action="store_true", default=False) + if not parser.has_option("--log"): + parser.add_option("", "--log", action="store_true", default=False, + help="Log all parts of flow graph to files (CAUTION: lots of data)") + + uhd_receiver.add_options(parser) + + demods = digital.modulation_utils.type_1_demods() + for mod in demods.values(): + mod.add_options(parser) + + (options, args) = parser.parse_args() + if len(args) != 0: + parser.print_help() + sys.exit(1) + + return (options, args) + + +if __name__ == "__main__": + demods = digital.modulation_utils.type_1_demods() + + (options, args) = get_options(demods) + + demod = demods[options.modulation] + tb = rx_psk_block(demod, options) + + print "\n*** SNR estimator is inaccurate below about 7dB" + print "*** BER estimator is inaccurate above about 10%\n" + updater = status_thread(tb) + + try: + tb.run() + except KeyboardInterrupt: + updater.done = True + updater = None |