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#!/usr/bin/env python
#
# Copyright 2008 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.
#
from gnuradio import gr, eng_notation, usrp
from optparse import OptionParser
from gnuradio.eng_option import eng_option
from receive_path import receive_path
import gnuradio.gr.gr_threading as _threading
import sys, time
n2s = eng_notation.num_to_str
class status_thread(_threading.Thread):
def __init__(self, tb):
_threading.Thread.__init__(self)
self.setDaemon(1)
self.tb = tb
self.done = False
self.start()
def run(self):
while not self.done:
print "Magnitude: %5.3f Variance: %5.3f Estimated SNR: %4.1f dB BER: %g" % (
tb.mag(), tb.var(), tb.snr(), tb.ber())
try:
time.sleep(1.0)
except KeyboardInterrupt:
self.done = True
class rx_bpsk_block(gr.top_block):
def __init__(self, options):
gr.top_block.__init__(self, "rx_mpsk")
print "USRP decimation rate", options.decim_rate
# Create a USRP source at desired board, sample rate, frequency, and gain
self._setup_usrp(options.which,
options.decim_rate,
options.rx_subdev_spec,
options.freq,
options.gain)
# Create the BERT receiver
if_rate = self._usrp.adc_rate()/options.decim_rate
self._receiver = receive_path(if_rate,
options.rate,
options.excess_bw,
options.costas_alpha,
options.costas_beta,
options.costas_max,
options.mm_gain_mu,
options.mm_gain_omega,
options.mm_omega_limit)
self.connect(self._usrp, self._receiver)
def _setup_usrp(self, which, decim, subdev_spec, freq, gain):
self._usrp = usrp.source_c(which=which, decim_rate=decim)
if subdev_spec is None:
subdev_spec = usrp.pick_rx_subdevice(self._usrp)
self._subdev = usrp.selected_subdev(self._usrp, subdev_spec)
mux = usrp.determine_rx_mux_value(self._usrp, subdev_spec)
self._usrp.set_mux(mux)
tr = self._usrp.tune(0, self._subdev, freq)
if not (tr):
print "Failed to tune to center frequency!"
else:
print "Center frequency:", n2s(freq)
if gain is None:
g = self._subdev.gain_range();
gain = float(g[0]+g[1])/2.0
self._subdev.set_gain(gain)
print "RX d'board:", self._subdev.side_and_name()
def snr(self):
return self._receiver.snr()
def mag(self):
return self._receiver.signal_mean()
def var(self):
return self._receiver.noise_variance()
def ber(self):
return self._receiver.ber()
def get_options():
parser = OptionParser(option_class=eng_option)
parser.add_option("-w", "--which", type="int", default=0,
help="select which USRP (0, 1, ...) (default is %default)",
metavar="NUM")
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("-f", "--freq", type="eng_float", default=None,
help="set frequency to FREQ", metavar="FREQ")
parser.add_option("-g", "--gain", type="eng_float", default=None,
help="set Rx gain (default is mid-point)")
parser.add_option("-r", "--rate", type="eng_float", default=250e3,
help="Select modulation symbol rate (default=%default)")
parser.add_option("-d", "--decim-rate", type="int", default=8,
help="Select USRP decimation rate (default=%default)")
parser.add_option("", "--excess-bw", type="eng_float", default=0.35,
help="Select RRC excess bandwidth (default=%default)")
parser.add_option("", "--costas-alpha", type="eng_float", default=0.2,
help="set Costas loop 1st order gain, (default=%default)")
parser.add_option("", "--costas-beta", type="eng_float", default=0.01,
help="set Costas loop 2nd order gain, (default=%default)")
parser.add_option("", "--costas-max", type="eng_float", default=0.005,
help="set Costas loop max freq (rad/sample) (default=%default)")
parser.add_option("", "--mm-gain-mu", type="eng_float", default=0.2,
help="set M&M loop 1st order gain, (default=%default)")
parser.add_option("", "--mm-gain-omega", type="eng_float", default=0.01,
help="set M&M loop 2nd order gain, (default=%default)")
parser.add_option("", "--mm-omega-limit", type="eng_float", default=0.005,
help="set M&M max timing error, (default=%default)")
(options, args) = parser.parse_args()
if len(args) != 0:
parser.print_help()
sys.exit(1)
if options.freq == None:
print "You must supply a frequency with -f or --freq"
sys.exit(1)
return (options, args)
if __name__ == "__main__":
(options, args) = get_options()
tb = rx_bpsk_block(options)
print "\n*** SNR estimator is inaccurate below about 7dB"
print "*** BER estimator is inaccurate above about 10%\n"
updater = status_thread(tb)
try:
tb.run()
except KeyboardInterrupt:
updater.done = True
updater = None
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