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   1 #
   2 # Copyright 2009 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 3, 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 from gnuradio import gr
  23 from gnuradio import usrp_options
  24 import receive_path
  25 from pick_bitrate2 import pick_rx_bitrate
  26 from gnuradio import eng_notation
  27
  28 def add_freq_option(parser):
  29     """
  30     Hackery that has the -f / --freq option set both tx_freq and rx_freq
  31     """
  32     def freq_callback(option, opt_str, value, parser):
  33         parser.values.rx_freq = value
  34         parser.values.tx_freq = value
  35
  36     if not parser.has_option('--freq'):
  37         parser.add_option('-f', '--freq', type="eng_float",
  38                           action="callback", callback=freq_callback,
  39                           help="set Tx and/or Rx frequency to FREQ [default=%default]",
  40                           metavar="FREQ")
  41
  42 def add_options(parser, expert):
  43     add_freq_option(parser)
  44     usrp_options.add_rx_options(parser)
  45     receive_path.receive_path.add_options(parser, expert)
  46     expert.add_option("", "--rx-freq", type="eng_float", default=None,
  47                           help="set Rx frequency to FREQ [default=%default]", metavar="FREQ")
  48     parser.add_option("-v", "--verbose", action="store_true", default=False)
  49
  50 class usrp_receive_path(gr.hier_block2):
  51
  52     def __init__(self, demod_class, rx_callback, options):
  53         '''
  54         See below for what options should hold
  55         '''
  56         gr.hier_block2.__init__(self, "usrp_receive_path",
  57                 gr.io_signature(0, 0, 0),                    # Input signature
  58                 gr.io_signature(0, 0, 0)) # Output signature
  59         if options.rx_freq is None:
  60             sys.stderr.write("-f FREQ or --freq FREQ or --rx-freq FREQ must be specified\n")
  61             raise SystemExit
  62         rx_path = receive_path.receive_path(demod_class, rx_callback, options)
  63         for attr in dir(rx_path): #forward the methods
  64             if not attr.startswith('_') and not hasattr(self, attr):
  65                 setattr(self, attr, getattr(rx_path, attr))
  66
  67         #setup usrp
  68         self._demod_class = demod_class
  69         self._setup_usrp_source(options)
  70
  71         # Set up resampler based on rate determined by _setup_usrp_source
  72         rs_taps = gr.firdes.low_pass_2(32, 32, 0.45, 0.1, 60)
  73         self.resampler = gr.pfb_arb_resampler_ccf(self.rs_rate, rs_taps)
  74
  75         #connect
  76         self.connect(self.u, self.resampler, rx_path)
  77
  78     def _setup_usrp_source(self, options):
  79         self.u = usrp_options.create_usrp_source(options)
  80         adc_rate = self.u.adc_rate()
  81         self.rs_rate = options.bitrate
  82         if options.verbose:
  83             print 'USRP Source:', self.u
  84
  85
  86         #(self._bitrate, self._samples_per_symbol, self._decim) = \
  87         #                pick_rx_bitrate(options.bitrate, self._demod_class.bits_per_symbol(), \
  88         #                                options.samples_per_symbol, options.decim, adc_rate,  \
  89         #                                self.u.get_decim_rates())
  90         (self._bitrate, self._samples_per_symbol, self._decim) = \
  91                         pick_rx_bitrate(options.bitrate, self._demod_class.bits_per_symbol(), \
  92                                         adc_rate, self.u.get_decim_rates())
  93
  94         print "USRP Decimation: ", self._decim
  95         print "Samples Per Symbol: ", self._samples_per_symbol
  96
  97         self.u.set_decim(self._decim)
  98
  99         if not self.u.set_center_freq(options.rx_freq):
 100             print "Failed to set Rx frequency to %s" % (eng_notation.num_to_str(options.rx_freq))
 101             raise ValueError, eng_notation.num_to_str(options.rx_freq)