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#
# Copyright 2005, 2006, 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 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, gru, blks2
from gnuradio import eng_notation
import copy
import sys
# /////////////////////////////////////////////////////////////////////////////
# transmit path
# /////////////////////////////////////////////////////////////////////////////
class transmit_path(gr.hier_block2):
def __init__(self, modulator_class, options):
'''
See below for what options should hold
'''
gr.hier_block2.__init__(self, "transmit_path",
gr.io_signature(0, 0, 0), # Input signature
gr.io_signature(1, 1, gr.sizeof_gr_complex)) # Output signature
options = copy.copy(options) # make a copy so we can destructively modify
self._verbose = options.verbose
self._tx_amplitude = options.tx_amplitude # digital amplitude sent to USRP
self._bitrate = options.bitrate # desired bit rate
self._samples_per_symbol = options.samples_per_symbol # desired samples/baud
self._modulator_class = modulator_class # the modulator_class we are using
# Get mod_kwargs
mod_kwargs = self._modulator_class.extract_kwargs_from_options(options)
# transmitter
modulator = self._modulator_class(**mod_kwargs)
self.packet_transmitter = \
blks2.mod_pkts(modulator,
access_code=None,
msgq_limit=4,
pad_for_usrp=True)
self.amp = gr.multiply_const_cc(1)
self.set_tx_amplitude(self._tx_amplitude)
# Display some information about the setup
if self._verbose:
self._print_verbage()
# Connect components in the flowgraph
self.connect(self.packet_transmitter, self.amp, self)
def set_tx_amplitude(self, ampl):
"""
Sets the transmit amplitude sent to the USRP in volts
@param: ampl 0 <= ampl < 1.
"""
self._tx_amplitude = max(0.0, min(ampl, 1))
self.amp.set_k(self._tx_amplitude)
def send_pkt(self, payload='', eof=False):
"""
Calls the transmitter method to send a packet
"""
return self.packet_transmitter.send_pkt(payload, eof)
def bitrate(self):
return self._bitrate
def samples_per_symbol(self):
return self._samples_per_symbol
def add_options(normal, expert):
"""
Adds transmitter-specific options to the Options Parser
"""
if not normal.has_option('--bitrate'):
normal.add_option("-r", "--bitrate", type="eng_float", default=100e3,
help="specify bitrate [default=%default].")
normal.add_option("", "--tx-amplitude", type="eng_float", default=0.250, metavar="AMPL",
help="set transmitter digital amplitude: 0 <= AMPL < 1 [default=%default]")
normal.add_option("-v", "--verbose", action="store_true", default=False)
expert.add_option("-S", "--samples-per-symbol", type="int", default=2,
help="set samples/symbol [default=%default]")
expert.add_option("", "--log", action="store_true", default=False,
help="Log all parts of flow graph to file (CAUTION: lots of data)")
# Make a static method to call before instantiation
add_options = staticmethod(add_options)
def _print_verbage(self):
"""
Prints information about the transmit path
"""
print "Tx amplitude %s" % (self._tx_amplitude)
print "modulation: %s" % (self._modulator_class.__name__)
print "bitrate: %sb/s" % (eng_notation.num_to_str(self._bitrate))
print "samples/symbol: %.4f" % (self._samples_per_symbol)
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