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#!/usr/bin/env python
#this file isn't ready to use now - gsm-receiver lacks realtime processing capability
#there are many underruns of buffer from usrp's samples, many blocks of samples get lost and
#receiver isn't prepared for this situation too well
from gnuradio import gr, gru, blks2
#, gsm
from gnuradio import usrp
from gnuradio.eng_option import eng_option
from optparse import OptionParser
from os import sys
for extdir in ['../../debug/src/lib','../../debug/src/lib/.libs']:
if extdir not in sys.path:
sys.path.append(extdir)
import gsm
def pick_subdevice(u):
if u.db[0][0].dbid() >= 0:
return (0, 0)
if u.db[1][0].dbid() >= 0:
return (1, 0)
return (0, 0)
class tune(gr.feval_dd):
def __init__(self, top_block):
gr.feval_dd.__init__(self)
self.top_block = top_block
# self.center_freq = 0
def eval(self, freq_offet):
# self.center_freq = self.center_freq - freq_offet
self.top_block.set_frequency(freq_offet)
return freq_offet
class gsm_receiver_first_blood(gr.top_block):
def __init__(self):
gr.top_block.__init__(self)
(options, args) = self._process_options()
self.tune_callback = tune(self)
self.options = options
self.args = args
self._set_rates()
self.source = self._set_source()
self.filtr = self._set_filter()
self.interpolator = self._set_interpolator()
self.receiver = self._set_receiver()
self.converter = self._set_converter()
self.sink = self._set_sink()
self.connect(self.source, self.filtr, self.interpolator, self.receiver, self.converter, self.sink)
def _set_sink(self):
nazwa_pliku_wy = self.options.outputfile
ujscie = gr.file_sink(gr.sizeof_float, nazwa_pliku_wy)
return ujscie
def _set_source(self):
options = self.options
fusb_block_size = gr.prefs().get_long('fusb', 'block_size', 4096)
fusb_nblocks = gr.prefs().get_long('fusb', 'nblocks', 16)
self.usrp = usrp.source_c(decim_rate=options.decim, fusb_block_size=fusb_block_size, fusb_nblocks=fusb_nblocks)
if options.rx_subdev_spec is None:
options.rx_subdev_spec = pick_subdevice(self.usrp)
self.usrp.set_mux(usrp.determine_rx_mux_value(self.usrp, options.rx_subdev_spec))
# determine the daughterboard subdevice
self.subdev = usrp.selected_subdev(self.usrp, options.rx_subdev_spec)
input_rate = self.usrp.adc_freq() / self.usrp.decim_rate()
# set initial values
if options.gain is None:
# if no gain was specified, use the mid-point in dB
g = self.subdev.gain_range()
options.gain = float(g[0]+g[1])/2
r = self.usrp.tune(0, self.subdev, options.freq)
self.subdev.set_gain(options.gain)
return self.usrp
def _set_rates(self):
options = self.options
clock_rate = 64e6
self.clock_rate = clock_rate
self.input_rate = clock_rate / options.decim
self.gsm_symb_rate = 1625000.0 / 6.0
self.sps = self.input_rate / self.gsm_symb_rate / self.options.osr
def _set_filter(self):
filter_cutoff = 145e3
filter_t_width = 10e3
offset = 0
# print "input_rate:", self.input_rate, "sample rate:", self.sps, " filter_cutoff:", filter_cutoff, " filter_t_width:", filter_t_width
filter_taps = gr.firdes.low_pass(1.0, self.input_rate, filter_cutoff, filter_t_width, gr.firdes.WIN_HAMMING)
filtr = gr.freq_xlating_fir_filter_ccf(1, filter_taps, offset, self.input_rate)
return filtr
def _set_converter(self):
v2s = gr.vector_to_stream(gr.sizeof_float, 142)
return v2s
def _set_interpolator(self):
interpolator = gr.fractional_interpolator_cc(0, self.sps)
return interpolator
def _set_receiver(self):
receiver = gsm.receiver_cf(self.tune_callback, self.options.osr)
return receiver
def _process_options(self):
parser = OptionParser(option_class=eng_option)
parser.add_option("-d", "--decim", type="int", default=128,
help="Set USRP decimation rate to DECIM [default=%default]")
parser.add_option("-I", "--inputfile", type="string", default="cfile",
help="Input filename")
parser.add_option("-O", "--outputfile", type="string", default="cfile2.out",
help="Output filename")
parser.add_option("-R", "--rx-subdev-spec", type="subdev", default=None,
help="Select USRP Rx side A or B (default=first one with a daughterboard)")
parser.add_option("-r", "--osr", type="int", default=4,
help="Oversampling ratio [default=%default]")
parser.add_option("-f", "--freq", type="eng_float", default="950.4M",
help="set frequency to FREQ", metavar="FREQ")
parser.add_option("-g", "--gain", type="eng_float", default=None,
help="Set gain in dB (default is midpoint)")
(options, args) = parser.parse_args ()
return (options, args)
def set_frequency(self, center_freq):
self.filtr.set_center_freq(center_freq)
def main():
try:
gsm_receiver_first_blood().run()
except KeyboardInterrupt:
pass
if __name__ == '__main__':
main()
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