This file is indexed.

/usr/bin/osmocom_spectrum_sense is in gr-osmosdr 0.1.4-12+b1.

This file is owned by root:root, with mode 0o755.

The actual contents of the file can be viewed below.

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
#! /usr/bin/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.
#

import osmosdr
from gnuradio import gr, eng_notation
from gnuradio import blocks
from gnuradio import audio
from gnuradio import filter
from gnuradio import fft
from gnuradio.eng_option import eng_option
from optparse import OptionParser
import sys
import math
import struct
import threading
from datetime import datetime

sys.stderr.write("Warning: this may have issues on some machines+Python version combinations to seg fault due to the callback in bin_statitics.\n\n")

class ThreadClass(threading.Thread):
    def run(self):
        return

class tune(gr.feval_dd):
    """
    This class allows C++ code to callback into python.
    """
    def __init__(self, tb):
        gr.feval_dd.__init__(self)
        self.tb = tb

    def eval(self, ignore):
        """
        This method is called from blocks.bin_statistics_f when it wants
        to change the center frequency.  This method tunes the front
        end to the new center frequency, and returns the new frequency
        as its result.
        """

        try:
            # We use this try block so that if something goes wrong
            # from here down, at least we'll have a prayer of knowing
            # what went wrong.  Without this, you get a very
            # mysterious:
            #
            #   terminate called after throwing an instance of
            #   'Swig::DirectorMethodException' Aborted
            #
            # message on stderr.  Not exactly helpful ;)

            new_freq = self.tb.set_next_freq()
            
            # wait until msgq is empty before continuing
            while(self.tb.msgq.full_p()):
                #print "msgq full, holding.."
                time.sleep(0.1)
            
            return new_freq

        except Exception, e:
            print "tune: Exception: ", e


class parse_msg(object):
    def __init__(self, msg):
        self.center_freq = msg.arg1()
        self.vlen = int(msg.arg2())
        assert(msg.length() == self.vlen * gr.sizeof_float)

        # FIXME consider using NumPy array
        t = msg.to_string()
        self.raw_data = t
        self.data = struct.unpack('%df' % (self.vlen,), t)


class my_top_block(gr.top_block):

    def __init__(self):
        gr.top_block.__init__(self)

        usage = "usage: %prog [options] min_freq max_freq"
        parser = OptionParser(option_class=eng_option, usage=usage)
        parser.add_option("-a", "--args", type="string", default="",
                          help="Device args [default=%default]")
        parser.add_option("-A", "--antenna", type="string", default=None,
                          help="Select antenna where appropriate")
        parser.add_option("-s", "--samp-rate", type="eng_float", default=None,
                          help="Set sample rate (bandwidth), minimum by default")
        parser.add_option("-g", "--gain", type="eng_float", default=None,
                          help="Set gain in dB (default is midpoint)")
        parser.add_option("", "--tune-delay", type="eng_float",
                          default=0.25, metavar="SECS",
                          help="Time to delay (in seconds) after changing frequency [default=%default]")
        parser.add_option("", "--dwell-delay", type="eng_float",
                          default=0.25, metavar="SECS",
                          help="Time to dwell (in seconds) at a given frequency [default=%default]")
        parser.add_option("-b", "--channel-bandwidth", type="eng_float",
                          default=6.25e3, metavar="Hz",
                          help="Channel bandwidth of fft bins in Hz [default=%default]")
        parser.add_option("-q", "--squelch-threshold", type="eng_float",
                          default=None, metavar="dB",
                          help="Squelch threshold in dB [default=%default]")
        parser.add_option("-F", "--fft-size", type="int", default=None,
                          help="Specify number of FFT bins [default=samp_rate/channel_bw]")
        parser.add_option("", "--real-time", action="store_true", default=False,
                          help="Attempt to enable real-time scheduling")

        (options, args) = parser.parse_args()
        if len(args) != 2:
            parser.print_help()
            sys.exit(1)

        self.channel_bandwidth = options.channel_bandwidth

        self.min_freq = eng_notation.str_to_num(args[0])
        self.max_freq = eng_notation.str_to_num(args[1])

        if self.min_freq > self.max_freq:
            # swap them
            self.min_freq, self.max_freq = self.max_freq, self.min_freq

        if not options.real_time:
            realtime = False
        else:
            # Attempt to enable realtime scheduling
            r = gr.enable_realtime_scheduling()
            if r == gr.RT_OK:
                realtime = True
            else:
                realtime = False
                print "Note: failed to enable realtime scheduling"

        # build graph
        self.u = osmosdr.source(options.args)

        try:
            self.u.get_sample_rates().start()
        except RuntimeError:
            print "Source has no sample rates (wrong device arguments?)."
            sys.exit(1)

        # Set the antenna
        if(options.antenna):
            self.u.set_antenna(options.antenna, 0)
        
        if options.samp_rate is None:
            options.samp_rate = self.u.get_sample_rates().start()

        self.u.set_sample_rate(options.samp_rate)
        self.usrp_rate = usrp_rate = self.u.get_sample_rate()

        if options.fft_size is None:
            self.fft_size = int(self.usrp_rate/self.channel_bandwidth)
        else:
            self.fft_size = options.fft_size
        
        self.squelch_threshold = options.squelch_threshold
        
        s2v = blocks.stream_to_vector(gr.sizeof_gr_complex, self.fft_size)

        mywindow = filter.window.blackmanharris(self.fft_size)
        ffter = fft.fft_vcc(self.fft_size, True, mywindow, True)
        power = 0
        for tap in mywindow:
            power += tap*tap

        c2mag = blocks.complex_to_mag_squared(self.fft_size)

        # FIXME the log10 primitive is dog slow
        #log = blocks.nlog10_ff(10, self.fft_size,
        #                       -20*math.log10(self.fft_size)-10*math.log10(power/self.fft_size))

        # Set the freq_step to 75% of the actual data throughput.
        # This allows us to discard the bins on both ends of the spectrum.

        self.freq_step = self.nearest_freq((0.75 * self.usrp_rate), self.channel_bandwidth)
        self.min_center_freq = self.min_freq + (self.freq_step/2) 
        nsteps = math.ceil((self.max_freq - self.min_freq) / self.freq_step)
        self.max_center_freq = self.min_center_freq + (nsteps * self.freq_step)

        self.next_freq = self.min_center_freq

        tune_delay  = max(0, int(round(options.tune_delay * usrp_rate / self.fft_size)))  # in fft_frames
        dwell_delay = max(1, int(round(options.dwell_delay * usrp_rate / self.fft_size))) # in fft_frames

        self.msgq = gr.msg_queue(1)
        self._tune_callback = tune(self)        # hang on to this to keep it from being GC'd
        stats = blocks.bin_statistics_f(self.fft_size, self.msgq,
                                        self._tune_callback, tune_delay,
                                        dwell_delay)

        # FIXME leave out the log10 until we speed it up
        #self.connect(self.u, s2v, ffter, c2mag, log, stats)
        self.connect(self.u, s2v, ffter, c2mag, stats)

        if options.gain is None:
            # if no gain was specified, use the mid-point in dB
            g = self.u.get_gain_range()
            options.gain = float(g.start()+g.stop())/2.0

        self.set_gain(options.gain)
        print "gain =", options.gain

    def set_next_freq(self):
        target_freq = self.next_freq
        self.next_freq = self.next_freq + self.freq_step
        if self.next_freq >= self.max_center_freq:
            self.next_freq = self.min_center_freq

        if not self.set_freq(target_freq):
            print "Failed to set frequency to", target_freq
            sys.exit(1)

        return target_freq


    def set_freq(self, target_freq):
        """
        Set the center frequency we're interested in.

        @param target_freq: frequency in Hz
        @rypte: bool
        """
        
        r = self.u.set_center_freq(target_freq)
        if r:
            return True

        return False

    def set_gain(self, gain):
        self.u.set_gain(gain)
    
    def nearest_freq(self, freq, channel_bandwidth):
        freq = round(freq / channel_bandwidth, 0) * channel_bandwidth
        return freq

def main_loop(tb):
    
    def bin_freq(i_bin, center_freq):
        #hz_per_bin = tb.usrp_rate / tb.fft_size
        freq = center_freq - (tb.usrp_rate / 2) + (tb.channel_bandwidth * i_bin)
        #print "freq original:",freq
        #freq = nearest_freq(freq, tb.channel_bandwidth)
        #print "freq rounded:",freq
        return freq
    
    bin_start = int(tb.fft_size * ((1 - 0.75) / 2))
    bin_stop = int(tb.fft_size - bin_start)

    while 1:

        # Get the next message sent from the C++ code (blocking call).
        # It contains the center frequency and the mag squared of the fft
        m = parse_msg(tb.msgq.delete_head())

        # m.center_freq is the center frequency at the time of capture
        # m.data are the mag_squared of the fft output
        # m.raw_data is a string that contains the binary floats.
        # You could write this as binary to a file.

        for i_bin in range(bin_start, bin_stop):

            center_freq = m.center_freq
            freq = bin_freq(i_bin, center_freq)
            #noise_floor_db = -174 + 10*math.log10(tb.channel_bandwidth)
            noise_floor_db = 10*math.log10(min(m.data)/tb.usrp_rate)
            power_db = 10*math.log10(m.data[i_bin]/tb.usrp_rate) - noise_floor_db

            if (power_db > tb.squelch_threshold) and (freq >= tb.min_freq) and (freq <= tb.max_freq):
                print datetime.now(), "center_freq", center_freq, "freq", freq, "power_db", power_db, "noise_floor_db", noise_floor_db

if __name__ == '__main__':
    t = ThreadClass()
    t.start()

    tb = my_top_block()
    try:
        tb.start()
        main_loop(tb)

    except KeyboardInterrupt:
        pass