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#!/usr/bin/env python
#
# Copyright 2007 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 2, 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, usrp, eng_notation
from usrp_sink import usrp_sink_c
import math
n2s = eng_notation.num_to_str
class sounder_tx(gr.hier_block2):
"""
Creates a top-level channel sounder block with the given parameters.
"""
def __init__(self, subdev_spec, freq, cal, verbose, max_delay, chip_rate, amplitude):
# Call hierarchical block constructor
# Top-level blocks have no inputs or outputs
gr.hier_block2.__init__(self,
"sounder_tx", # Block typename
gr.io_signature(0,0,0), # Input signature
gr.io_signature(0,0,0)) # Output signature
self._freq = freq
self._cal = cal
self._verbose = verbose
self._max_delay = max_delay
self._u = usrp_sink_c(0, subdev_spec, chip_rate, self._freq, self._cal, verbose)
self._chip_rate = self._u._if_rate
self._resolution = 1.0/self._chip_rate
min_chips = int(math.ceil(2.0*self._max_delay * self._chip_rate))
degree = int(math.ceil(math.log(min_chips)/math.log(2)))
self._length = 2**degree-1
self._glfsr = gr.glfsr_source_b(degree)
self._mapper = gr.chunks_to_symbols_bc((-amplitude+0j, amplitude+0j), 1)
if self._verbose:
print "Actual chip rate is", n2s(self._chip_rate), "chips/sec"
print "Resolution is", n2s(self._resolution), "sec"
print "Using specified maximum delay spread of", self._max_delay, "sec"
print "Mininum sequence length needed is", n2s(min_chips), "chips"
print "Using PN sequence of degree", degree, "length", self._length
print "Output amplitude is", amplitude
self.define_component("glfsr", self._glfsr)
self.define_component("mapper", self._mapper)
self.define_component("usrp", self._u)
self.connect("glfsr", 0, "mapper", 0)
self.connect("mapper", 0, "usrp", 0)
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