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#!/usr/bin/env python
#
# Copyright 2005,2006 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, gru, blks
from gnuradio import usrp
from gnuradio import eng_notation
import copy
import sys
# from current dir
from pick_bitrate import pick_rx_bitrate
import ofdm
# /////////////////////////////////////////////////////////////////////////////
# receive path
# /////////////////////////////////////////////////////////////////////////////
class receive_path(gr.hier_block):
def __init__(self, fg, rx_callback, options):
options = copy.copy(options) # make a copy so we can destructively modify
self._verbose = options.verbose
self._log = options.log
self._rx_callback = rx_callback # this callback is fired when there's a packet available
if 0:
chan_coeffs = gr.firdes.low_pass (1.0, # gain
2.0, # sampling rate
bw, # midpoint of trans. band
1*bw, # width of trans. band
gr.firdes.WIN_KAISER) # filter type
else:
chan_coeffs = [ 1.0, 0.0, 0 ]
self.chan_filt = gr.fft_filter_ccc(1, chan_coeffs)
self.ofdm_demod = ofdm.ofdm_demod(fg, options)
# receiver
self.packet_receiver = \
blks.demod_ofdm_pkts(fg,
self.ofdm_demod,
access_code=None,
callback=self._rx_callback,
threshold=-1)
# Carrier Sensing Blocks
alpha = 0.001
thresh = 30 # in dB, will have to adjust
self.probe = gr.probe_avg_mag_sqrd_c(thresh,alpha)
fg.connect(self.chan_filt, self.probe)
# Display some information about the setup
if self._verbose:
self._print_verbage()
fg.connect(self.chan_filt, self.packet_receiver)
#fg.connect(self.chan_filt, gr.file_sink(gr.sizeof_gr_complex, "ofdmrx_chflt.dat"))
gr.hier_block.__init__(self, fg, self.chan_filt, None)
def carrier_sensed(self):
"""
Return True if we think carrier is present.
"""
#return self.probe.level() > X
return self.probe.unmuted()
def carrier_threshold(self):
"""
Return current setting in dB.
"""
return self.probe.threshold()
def set_carrier_threshold(self, threshold_in_db):
"""
Set carrier threshold.
@param threshold_in_db: set detection threshold
@type threshold_in_db: float (dB)
"""
self.probe.set_threshold(threshold_in_db)
def add_options(normal, expert):
"""
Adds receiver-specific options to the Options Parser
"""
normal.add_option("-v", "--verbose", action="store_true", default=False)
expert.add_option("", "--log", action="store_true", default=False,
help="Log all parts of flow graph to files (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 receive path
"""
print "Using RX d'board %s" % (self.subdev.side_and_name(),)
print "Rx gain: %g" % (self.gain,)
print "modulation: %s" % (self._demod_class.__name__)
print "bitrate: %sb/s" % (eng_notation.num_to_str(self._bitrate))
print "samples/symbol: %3d" % (self._samples_per_symbol)
print "decim: %3d" % (self._decim)
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