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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28 | |
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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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123 | adc_rate = self.u.adc_rate() |
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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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128 | self._samples_per_symbol, self._decim, adc_rate) |
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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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