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#!/usr/bin/env python
#
# Copyright 2011-2013 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, digital, filter
from gnuradio import blocks
from gnuradio import channels
from gnuradio import eng_notation
from gnuradio.eng_arg import eng_float, intx
from argparse import ArgumentParser
import sys
try:
import scipy
except ImportError:
print "Error: could not import scipy (http://www.scipy.org/)"
sys.exit(1)
try:
import pylab
except ImportError:
print "Error: could not import pylab (http://matplotlib.sourceforge.net/)"
sys.exit(1)
class example_fll(gr.top_block):
def __init__(self, N, sps, rolloff, ntaps, bw, noise, foffset, toffset, poffset):
gr.top_block.__init__(self)
rrc_taps = filter.firdes.root_raised_cosine(
sps, sps, 1.0, rolloff, ntaps)
data = 2.0*scipy.random.randint(0, 2, N) - 1.0
data = scipy.exp(1j*poffset) * data
self.src = blocks.vector_source_c(data.tolist(), False)
self.rrc = filter.interp_fir_filter_ccf(sps, rrc_taps)
self.chn = channels.channel_model(noise, foffset, toffset)
self.fll = digital.fll_band_edge_cc(sps, rolloff, ntaps, bw)
self.vsnk_src = blocks.vector_sink_c()
self.vsnk_fll = blocks.vector_sink_c()
self.vsnk_frq = blocks.vector_sink_f()
self.vsnk_phs = blocks.vector_sink_f()
self.vsnk_err = blocks.vector_sink_f()
self.connect(self.src, self.rrc, self.chn, self.fll, self.vsnk_fll)
self.connect(self.rrc, self.vsnk_src)
self.connect((self.fll,1), self.vsnk_frq)
self.connect((self.fll,2), self.vsnk_phs)
self.connect((self.fll,3), self.vsnk_err)
def main():
parser = ArgumentParser(conflict_handler="resolve")
parser.add_argument("-N", "--nsamples", type=int, default=2000,
help="Set the number of samples to process [default=%(default)r]")
parser.add_argument("-S", "--sps", type=int, default=4,
help="Set the samples per symbol [default=%(default)r]")
parser.add_argument("-r", "--rolloff", type=eng_float, default=0.35,
help="Set the rolloff factor [default=%(default)r]")
parser.add_argument("-W", "--bandwidth", type=eng_float, default=2*scipy.pi/100.0,
help="Set the loop bandwidth [default=%(default)r]")
parser.add_argument("-n", "--ntaps", type=int, default=45,
help="Set the number of taps in the filters [default=%(default)r]")
parser.add_argument("--noise", type=eng_float, default=0.0,
help="Set the simulation noise voltage [default=%(default)r]")
parser.add_argument("-f", "--foffset", type=eng_float, default=0.2,
help="Set the simulation's normalized frequency offset (in Hz) [default=%(default)r]")
parser.add_argument("-t", "--toffset", type=eng_float, default=1.0,
help="Set the simulation's timing offset [default=%(default)r]")
parser.add_argument("-p", "--poffset", type=eng_float, default=0.0,
help="Set the simulation's phase offset [default=%(default)r]")
args = parser.parse_args()
# Adjust N for the interpolation by sps
args.nsamples = args.nsamples // args.sps
# Set up the program-under-test
put = example_fll(args.nsamples, args.sps, args.rolloff,
args.ntaps, args.bandwidth, args.noise,
args.foffset, args.toffset, args.poffset)
put.run()
data_src = scipy.array(put.vsnk_src.data())
data_err = scipy.array(put.vsnk_err.data())
# Convert the FLL's LO frequency from rads/sec to Hz
data_frq = scipy.array(put.vsnk_frq.data()) / (2.0*scipy.pi)
# adjust this to align with the data. There are 2 filters of
# ntaps long and the channel introduces another 4 sample delay.
data_fll = scipy.array(put.vsnk_fll.data()[2*args.ntaps-4:])
# Plot the FLL's LO frequency
f1 = pylab.figure(1, figsize=(12,10))
s1 = f1.add_subplot(2,2,1)
s1.plot(data_frq)
s1.set_title("FLL LO")
s1.set_xlabel("Samples")
s1.set_ylabel("Frequency (normalized Hz)")
# Plot the FLL's error
s2 = f1.add_subplot(2,2,2)
s2.plot(data_err)
s2.set_title("FLL Error")
s2.set_xlabel("Samples")
s2.set_ylabel("FLL Loop error")
# Plot the IQ symbols
s3 = f1.add_subplot(2,2,3)
s3.plot(data_src.real, data_src.imag, "o")
s3.plot(data_fll.real, data_fll.imag, "rx")
s3.set_title("IQ")
s3.set_xlabel("Real part")
s3.set_ylabel("Imag part")
# Plot the symbols in time
s4 = f1.add_subplot(2,2,4)
s4.plot(data_src.real, "o-")
s4.plot(data_fll.real, "rx-")
s4.set_title("Symbols")
s4.set_xlabel("Samples")
s4.set_ylabel("Real Part of Signals")
pylab.show()
if __name__ == "__main__":
try:
main()
except KeyboardInterrupt:
pass
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