[319] | 1 | #!/usr/bin/env python |
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| 2 | # |
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| 3 | # Copyright 2005,2006,2007,2009 Free Software Foundation, Inc. |
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| 4 | # |
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| 5 | # This file is part of GNU Radio |
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| 6 | # |
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| 7 | # GNU Radio is free software; you can redistribute it and/or modify |
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| 8 | # it under the terms of the GNU General Public License as published by |
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| 9 | # the Free Software Foundation; either version 3, or (at your option) |
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| 10 | # any later version. |
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| 11 | # |
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| 12 | # GNU Radio is distributed in the hope that it will be useful, |
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| 13 | # but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 14 | # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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| 15 | # GNU General Public License for more details. |
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| 16 | # |
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| 17 | # You should have received a copy of the GNU General Public License |
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| 18 | # along with GNU Radio; see the file COPYING. If not, write to |
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| 19 | # the Free Software Foundation, Inc., 51 Franklin Street, |
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| 20 | # Boston, MA 02110-1301, USA. |
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| 21 | # |
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| 22 | |
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| 23 | from gnuradio import gr, gru, blks2 |
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| 24 | from gnuradio import usrp |
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| 25 | from gnuradio import eng_notation |
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| 26 | import copy |
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| 27 | import sys |
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[368] | 28 | |
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[319] | 29 | # from current dir |
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| 30 | from pick_bitrate import pick_rx_bitrate |
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| 31 | import usrp_options |
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| 32 | |
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| 33 | # ///////////////////////////////////////////////////////////////////////////// |
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| 34 | # receive path |
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| 35 | # ///////////////////////////////////////////////////////////////////////////// |
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| 36 | |
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| 37 | class receive_path(gr.hier_block2): |
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| 38 | def __init__(self, demod_class, rx_callback, options): |
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| 39 | |
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| 40 | gr.hier_block2.__init__(self, "receive_path", |
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| 41 | gr.io_signature(0, 0, 0), # Input signature |
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| 42 | gr.io_signature(0, 0, 0)) # Output signature |
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| 43 | |
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| 44 | options = copy.copy(options) # make a copy so we can destructively modify |
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| 45 | |
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| 46 | self._verbose = options.verbose |
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| 47 | self._rx_freq = options.rx_freq # receiver's center frequency |
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| 48 | self._rx_gain = options.rx_gain # receiver's gain |
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| 49 | self._bitrate = options.bitrate # desired bit rate |
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| 50 | self._decim = options.decim # Decimating rate for the USRP (prelim) |
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| 51 | self._samples_per_symbol = options.samples_per_symbol # desired samples/symbol |
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| 52 | |
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| 53 | self._rx_callback = rx_callback # this callback is fired when there's a packet available |
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| 54 | self._demod_class = demod_class # the demodulator_class we're using |
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| 55 | |
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| 56 | if self._rx_freq is None: |
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| 57 | sys.stderr.write("-f FREQ or --freq FREQ or --rx-freq FREQ must be specified\n") |
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| 58 | raise SystemExit |
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| 59 | |
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| 60 | # Set up USRP source; also adjusts decim, samples_per_symbol, and bitrate |
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| 61 | self._setup_usrp_source(options) |
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| 62 | |
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| 63 | if options.show_rx_gain_range: |
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| 64 | print "Rx Gain Range: minimum = %g, maximum = %g, step size = %g"%tuple(self.u.gain_range()) |
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| 65 | |
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| 66 | self.set_gain(options.rx_gain) |
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| 67 | |
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| 68 | # Set RF frequency |
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| 69 | ok = self.set_freq(self._rx_freq) |
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| 70 | if not ok: |
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| 71 | print "Failed to set Rx frequency to %s" % (eng_notation.num_to_str(self._rx_freq)) |
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| 72 | raise ValueError, eng_notation.num_to_str(self._rx_freq) |
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| 73 | |
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| 74 | # copy the final answers back into options for use by demodulator |
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| 75 | options.samples_per_symbol = self._samples_per_symbol |
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| 76 | options.bitrate = self._bitrate |
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| 77 | options.decim = self._decim |
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| 78 | |
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| 79 | # Get demod_kwargs |
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| 80 | demod_kwargs = self._demod_class.extract_kwargs_from_options(options) |
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| 81 | |
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| 82 | # Design filter to get actual channel we want |
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| 83 | sw_decim = 1 |
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| 84 | chan_coeffs = gr.firdes.low_pass (1.0, # gain |
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| 85 | sw_decim * self._samples_per_symbol, # sampling rate |
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| 86 | 1.0, # midpoint of trans. band |
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| 87 | 0.5, # width of trans. band |
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| 88 | gr.firdes.WIN_HANN) # filter type |
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| 89 | |
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| 90 | # Decimating channel filter |
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| 91 | # complex in and out, float taps |
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| 92 | self.chan_filt = gr.fft_filter_ccc(sw_decim, chan_coeffs) |
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| 93 | #self.chan_filt = gr.fir_filter_ccf(sw_decim, chan_coeffs) |
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| 94 | |
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| 95 | # receiver |
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| 96 | self.packet_receiver = \ |
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| 97 | blks2.demod_pkts(self._demod_class(**demod_kwargs), |
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| 98 | access_code=None, |
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| 99 | callback=self._rx_callback, |
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| 100 | threshold=-1) |
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| 101 | |
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| 102 | # Carrier Sensing Blocks |
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| 103 | alpha = 0.001 |
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| 104 | thresh = 30 # in dB, will have to adjust |
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| 105 | |
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| 106 | if options.log_rx_power == True: |
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| 107 | self.probe = gr.probe_avg_mag_sqrd_cf(thresh,alpha) |
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| 108 | self.power_sink = gr.file_sink(gr.sizeof_float, "rxpower.dat") |
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| 109 | self.connect(self.chan_filt, self.probe, self.power_sink) |
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| 110 | else: |
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| 111 | self.probe = gr.probe_avg_mag_sqrd_c(thresh,alpha) |
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| 112 | self.connect(self.chan_filt, self.probe) |
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| 113 | |
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| 114 | # Display some information about the setup |
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| 115 | if self._verbose: |
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| 116 | self._print_verbage() |
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| 117 | |
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| 118 | self.connect(self.u, self.chan_filt, self.packet_receiver) |
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| 119 | |
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| 120 | def _setup_usrp_source(self, options): |
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| 121 | |
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| 122 | self.u = usrp_options.create_usrp_source(options) |
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[368] | 123 | adc_rate = self.u.adc_rate() |
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[319] | 124 | |
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| 125 | # derive values of bitrate, samples_per_symbol, and decim from desired info |
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| 126 | (self._bitrate, self._samples_per_symbol, self._decim) = \ |
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| 127 | pick_rx_bitrate(self._bitrate, self._demod_class.bits_per_symbol(), \ |
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[368] | 128 | self._samples_per_symbol, self._decim, adc_rate) |
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[319] | 129 | |
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| 130 | self.u.set_decim(self._decim) |
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| 131 | |
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| 132 | def set_freq(self, target_freq): |
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| 133 | """ |
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| 134 | Set the center frequency we're interested in. |
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| 135 | |
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| 136 | @param target_freq: frequency in Hz |
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| 137 | @rypte: bool |
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| 138 | |
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| 139 | Tuning is a two step process. First we ask the front-end to |
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| 140 | tune as close to the desired frequency as it can. Then we use |
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| 141 | the result of that operation and our target_frequency to |
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| 142 | determine the value for the digital up converter. |
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| 143 | """ |
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| 144 | return self.u.set_center_freq(target_freq) |
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| 145 | |
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| 146 | def set_gain(self, gain): |
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| 147 | """ |
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| 148 | Sets the analog gain in the USRP |
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| 149 | """ |
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| 150 | return self.u.set_gain(gain) |
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| 151 | |
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| 152 | def bitrate(self): |
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| 153 | return self._bitrate |
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| 154 | |
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| 155 | def samples_per_symbol(self): |
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| 156 | return self._samples_per_symbol |
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| 157 | |
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| 158 | def decim(self): |
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| 159 | return self._decim |
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| 160 | |
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| 161 | def carrier_sensed(self): |
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| 162 | """ |
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| 163 | Return True if we think carrier is present. |
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| 164 | """ |
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| 165 | #return self.probe.level() > X |
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| 166 | return self.probe.unmuted() |
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| 167 | |
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| 168 | def carrier_threshold(self): |
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| 169 | """ |
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| 170 | Return current setting in dB. |
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| 171 | """ |
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| 172 | return self.probe.threshold() |
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| 173 | |
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| 174 | def set_carrier_threshold(self, threshold_in_db): |
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| 175 | """ |
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| 176 | Set carrier threshold. |
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| 177 | |
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| 178 | @param threshold_in_db: set detection threshold |
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| 179 | @type threshold_in_db: float (dB) |
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| 180 | """ |
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| 181 | self.probe.set_threshold(threshold_in_db) |
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| 182 | |
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| 183 | @staticmethod |
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| 184 | def add_options(normal, expert): |
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| 185 | """ |
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| 186 | Adds receiver-specific options to the Options Parser |
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| 187 | """ |
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| 188 | add_freq_option(normal) |
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| 189 | if not normal.has_option("--bitrate"): |
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| 190 | normal.add_option("-r", "--bitrate", type="eng_float", default=None, |
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| 191 | help="specify bitrate. samples-per-symbol and interp/decim will be derived.") |
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| 192 | usrp_options.add_rx_options(normal, expert) |
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| 193 | normal.add_option("-v", "--verbose", action="store_true", default=False) |
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| 194 | expert.add_option("-S", "--samples-per-symbol", type="int", default=None, |
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| 195 | help="set samples/symbol [default=%default]") |
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| 196 | expert.add_option("", "--rx-freq", type="eng_float", default=None, |
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| 197 | help="set Rx frequency to FREQ [default=%default]", metavar="FREQ") |
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| 198 | expert.add_option("", "--log", action="store_true", default=False, |
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| 199 | help="Log all parts of flow graph to files (CAUTION: lots of data)") |
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| 200 | expert.add_option("", "--log-rx-power", action="store_true", default=False, |
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| 201 | help="Log receive signal power to file (CAUTION: lots of data)") |
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| 202 | |
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| 203 | def _print_verbage(self): |
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| 204 | """ |
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| 205 | Prints information about the receive path |
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| 206 | """ |
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| 207 | print "\nReceive Path:" |
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| 208 | print "USRP %s" % (self.u,) |
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| 209 | print "Rx gain: %g" % (self.u.gain(),) |
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| 210 | print "modulation: %s" % (self._demod_class.__name__) |
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| 211 | print "bitrate: %sb/s" % (eng_notation.num_to_str(self._bitrate)) |
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| 212 | print "samples/symbol: %3d" % (self._samples_per_symbol) |
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| 213 | print "decim: %3d" % (self._decim) |
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| 214 | print "Rx Frequency: %s" % (eng_notation.num_to_str(self._rx_freq)) |
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| 215 | |
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| 216 | def add_freq_option(parser): |
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| 217 | """ |
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| 218 | Hackery that has the -f / --freq option set both tx_freq and rx_freq |
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| 219 | """ |
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| 220 | def freq_callback(option, opt_str, value, parser): |
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| 221 | parser.values.rx_freq = value |
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| 222 | parser.values.tx_freq = value |
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| 223 | |
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| 224 | if not parser.has_option('--freq'): |
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| 225 | parser.add_option('-f', '--freq', type="eng_float", |
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| 226 | action="callback", callback=freq_callback, |
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| 227 | help="set Tx and/or Rx frequency to FREQ [default=%default]", |
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| 228 | metavar="FREQ") |
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