3 # Copyright 2005,2006 Free Software Foundation, Inc.
5 # This file is part of GNU Radio
7 # GNU Radio is free software; you can redistribute it and/or modify
8 # it under the terms of the GNU General Public License as published by
9 # the Free Software Foundation; either version 3, or (at your option)
12 # GNU Radio is distributed in the hope that it will be useful,
13 # but WITHOUT ANY WARRANTY; without even the implied warranty of
14 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 # GNU General Public License for more details.
17 # You should have received a copy of the GNU General Public License
18 # along with GNU Radio; see the file COPYING. If not, write to
19 # the Free Software Foundation, Inc., 51 Franklin Street,
20 # Boston, MA 02110-1301, USA.
23 from gnuradio import gr, gru, blks
24 from gnuradio import eng_notation
28 # /////////////////////////////////////////////////////////////////////////////
30 # /////////////////////////////////////////////////////////////////////////////
32 class receive_path(gr.hier_block):
33 def __init__(self, fg, demod_class, rx_callback, options):
35 options = copy.copy(options) # make a copy so we can destructively modify
37 self._verbose = options.verbose
38 self._bitrate = options.bitrate # desired bit rate
39 self._samples_per_symbol = options.samples_per_symbol # desired samples/symbol
41 self._rx_callback = rx_callback # this callback is fired when there's a packet available
42 self._demod_class = demod_class # the demodulator_class we're using
45 demod_kwargs = self._demod_class.extract_kwargs_from_options(options)
47 # Design filter to get actual channel we want
49 chan_coeffs = gr.firdes.low_pass (1.0, # gain
50 sw_decim * self._samples_per_symbol, # sampling rate
51 1.0, # midpoint of trans. band
52 0.5, # width of trans. band
53 gr.firdes.WIN_HANN) # filter type
54 self.channel_filter = gr.fft_filter_ccc(sw_decim, chan_coeffs)
57 self.packet_receiver = \
59 self._demod_class(fg, **demod_kwargs),
61 callback=self._rx_callback,
64 # Carrier Sensing Blocks
66 thresh = 30 # in dB, will have to adjust
67 self.probe = gr.probe_avg_mag_sqrd_c(thresh,alpha)
69 # Display some information about the setup
73 # connect the channel input filter to the carrier power detector
74 fg.connect(self.channel_filter, self.probe)
76 # connect channel filter to the packet receiver
77 fg.connect(self.channel_filter, self.packet_receiver)
79 gr.hier_block.__init__(self, fg, self.channel_filter, None)
84 def samples_per_symbol(self):
85 return self._samples_per_symbol
87 def carrier_sensed(self):
89 Return True if we think carrier is present.
91 #return self.probe.level() > X
92 return self.probe.unmuted()
94 def carrier_threshold(self):
96 Return current setting in dB.
98 return self.probe.threshold()
100 def set_carrier_threshold(self, threshold_in_db):
102 Set carrier threshold.
104 @param threshold_in_db: set detection threshold
105 @type threshold_in_db: float (dB)
107 self.probe.set_threshold(threshold_in_db)
110 def add_options(normal, expert):
112 Adds receiver-specific options to the Options Parser
114 if not normal.has_option("--bitrate"):
115 normal.add_option("-r", "--bitrate", type="eng_float", default=100e3,
116 help="specify bitrate [default=%default].")
117 normal.add_option("", "--show-rx-gain-range", action="store_true", default=False,
118 help="print min and max Rx gain available on selected daughterboard")
119 normal.add_option("-v", "--verbose", action="store_true", default=False)
120 expert.add_option("-S", "--samples-per-symbol", type="int", default=2,
121 help="set samples/symbol [default=%default]")
122 expert.add_option("", "--log", action="store_true", default=False,
123 help="Log all parts of flow graph to files (CAUTION: lots of data)")
125 # Make a static method to call before instantiation
126 add_options = staticmethod(add_options)
129 def _print_verbage(self):
131 Prints information about the receive path
133 print "\nReceive Path:"
134 print "modulation: %s" % (self._demod_class.__name__)
135 print "bitrate: %sb/s" % (eng_notation.num_to_str(self._bitrate))
136 print "samples/symbol: %3d" % (self._samples_per_symbol)