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Diffstat (limited to 'gr-digital/examples/narrowband/receive_path.py')
| -rw-r--r-- | gr-digital/examples/narrowband/receive_path.py | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/gr-digital/examples/narrowband/receive_path.py b/gr-digital/examples/narrowband/receive_path.py new file mode 100644 index 000000000..1c5e58963 --- /dev/null +++ b/gr-digital/examples/narrowband/receive_path.py @@ -0,0 +1,145 @@ +#!/usr/bin/env python +# +# Copyright 2005-2007,2011 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, gru +from gnuradio import eng_notation +from gnuradio import digital + +import copy +import sys + +# ///////////////////////////////////////////////////////////////////////////// +# receive path +# ///////////////////////////////////////////////////////////////////////////// + +class receive_path(gr.hier_block2): + def __init__(self, demod_class, rx_callback, options): + gr.hier_block2.__init__(self, "receive_path", + gr.io_signature(1, 1, gr.sizeof_gr_complex), + gr.io_signature(0, 0, 0)) + + options = copy.copy(options) # make a copy so we can destructively modify + + self._verbose = options.verbose + self._bitrate = options.bitrate # desired bit rate + + self._rx_callback = rx_callback # this callback is fired when a packet arrives + self._demod_class = demod_class # the demodulator_class we're using + + # Get demod_kwargs + demod_kwargs = self._demod_class.extract_kwargs_from_options(options) + + # Build the demodulator + self.demodulator = self._demod_class(**demod_kwargs) + + # Design filter to get actual channel we want + sw_decim = 1 + chan_coeffs = gr.firdes.low_pass (1.0, # gain + sw_decim * self.samples_per_symbol(), # sampling rate + 1.0, # midpoint of trans. band + 0.5, # width of trans. band + gr.firdes.WIN_HANN) # filter type + self.channel_filter = gr.fft_filter_ccc(sw_decim, chan_coeffs) + + # receiver + self.packet_receiver = \ + digital.demod_pkts(self.demodulator, + access_code=None, + callback=self._rx_callback, + threshold=-1) + + # Carrier Sensing Blocks + alpha = 0.001 + thresh = 30 # in dB, will have to adjust + self.probe = gr.probe_avg_mag_sqrd_c(thresh,alpha) + + # Display some information about the setup + if self._verbose: + self._print_verbage() + + # connect block input to channel filter + self.connect(self, self.channel_filter) + + # connect the channel input filter to the carrier power detector + self.connect(self.channel_filter, self.probe) + + # connect channel filter to the packet receiver + self.connect(self.channel_filter, self.packet_receiver) + + def bitrate(self): + return self._bitrate + + def samples_per_symbol(self): + return self.demodulator._samples_per_symbol + + def differential(self): + return self.demodulator._differential + + def carrier_sensed(self): + """ + Return True if we think carrier is present. + """ + #return self.probe.level() > X + return self.probe.unmuted() + + def carrier_threshold(self): + """ + Return current setting in dB. + """ + return self.probe.threshold() + + def set_carrier_threshold(self, threshold_in_db): + """ + Set carrier threshold. + + @param threshold_in_db: set detection threshold + @type threshold_in_db: float (dB) + """ + self.probe.set_threshold(threshold_in_db) + + + def add_options(normal, expert): + """ + Adds receiver-specific options to the Options Parser + """ + if not normal.has_option("--bitrate"): + normal.add_option("-r", "--bitrate", type="eng_float", default=100e3, + help="specify bitrate [default=%default].") + normal.add_option("-v", "--verbose", action="store_true", default=False) + expert.add_option("-S", "--samples-per-symbol", type="float", default=2, + help="set samples/symbol [default=%default]") + expert.add_option("", "--log", action="store_true", default=False, + help="Log all parts of flow graph to files (CAUTION: lots of data)") + + # Make a static method to call before instantiation + add_options = staticmethod(add_options) + + + def _print_verbage(self): + """ + Prints information about the receive path + """ + print "\nReceive Path:" + print "modulation: %s" % (self._demod_class.__name__) + print "bitrate: %sb/s" % (eng_notation.num_to_str(self._bitrate)) + print "samples/symbol: %.4f" % (self.samples_per_symbol()) + print "Differential: %s" % (self.differential()) |