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#!/usr/bin/env python
#
# Copyright 2006,2007,2009 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, usrp, optfir, eng_notation, pager
from gnuradio.eng_option import eng_option
from optparse import OptionParser
import time, os, sys
"""
This example application demonstrates receiving and demodulating the
FLEX pager protocol.
The following are required command line parameters:
-f FREQ USRP receive frequency
The following are optional command line parameters:
-R SUBDEV Daughter board specification, defaults to first found
-F FILE Read samples from a file instead of USRP.
-c FREQ Calibration offset. Gets added to receive frequency.
Defaults to 0.0 Hz.
-g GAIN Daughterboard gain setting. Defaults to mid-range.
-l Log flow graph to files (LOTS of data)
-v Verbose output
Once the program is running, ctrl-break (Ctrl-C) stops operation.
"""
class app_top_block(gr.top_block):
def __init__(self, options, queue):
gr.top_block.__init__(self, "usrp_flex")
self.options = options
self.offset = 0.0
self.adj_time = time.time()
self.verbose = options.verbose
if options.from_file is None:
# Set up USRP source with specified RX daughterboard
self.src = usrp.source_c()
if options.rx_subdev_spec == None:
options.rx_subdev_spec = usrp.pick_rx_subdevice(self.src)
self.subdev = usrp.selected_subdev(self.src, options.rx_subdev_spec)
self.src.set_mux(usrp.determine_rx_mux_value(self.src, options.rx_subdev_spec))
# Grab 250 KHz of spectrum (sample rate becomes 250 ksps complex)
self.src.set_decim_rate(256)
# If no gain specified, set to midrange
if options.gain is None:
g = self.subdev.gain_range()
options.gain = (g[0]+g[1])/2.0
self.subdev.set_gain(options.gain)
# Tune daughterboard
actual_frequency = options.frequency+options.calibration
tune_result = usrp.tune(self.src, 0, self.subdev, actual_frequency)
if not tune_result:
sys.stderr.write("Failed to set center frequency to "+`actual_frequency`+"\n")
sys.exit(1)
if options.verbose:
print "Using RX daughterboard", self.subdev.side_and_name()
print "USRP gain is", options.gain
print "USRP tuned to", actual_frequency
else:
# Use supplied file as source of samples
self.src = gr.file_source(gr.sizeof_gr_complex, options.from_file)
if options.verbose:
print "Reading samples from", options.from_file
if options.log and not options.from_file:
usrp_sink = gr.file_sink(gr.sizeof_gr_complex, 'usrp.dat')
self.connect(self.src, usrp_sink)
# Set up 22KHz-wide bandpass about center frequency. Decimate by 10
# to get channel rate of 25Ksps
taps = optfir.low_pass(1.0, # Filter gain
250e3, # Sample rate
11000, # One-sided modulation bandwidth
12500, # One-sided channel bandwidth
0.1, # Passband ripple
60) # Stopband attenuation
if options.verbose:
print "Channel filter has", len(taps), "taps."
self.chan = gr.freq_xlating_fir_filter_ccf(10, # Decimation rate
taps, # Filter taps
0.0, # Offset frequency
250e3) # Sample rate
if options.log:
chan_sink = gr.file_sink(gr.sizeof_gr_complex, 'chan.dat')
self.connect(self.chan, chan_sink)
# FLEX protocol demodulator
self.flex = pager.flex_demod(queue, options.frequency, options.verbose, options.log)
self.connect(self.src, self.chan, self.flex)
def freq_offset(self):
return self.flex.dc_offset()*1600
def adjust_freq(self):
if time.time() - self.adj_time > 1.6: # Only do it once per FLEX frame
self.adj_time = time.time()
self.offset -= self.freq_offset()
self.chan.set_center_freq(self.offset)
if self.verbose:
print "Channel frequency offset (Hz):", int(self.offset)
def main():
parser = OptionParser(option_class=eng_option)
parser.add_option("-f", "--frequency", type="eng_float", default=None,
help="set receive frequency to Hz", metavar="Hz")
parser.add_option("-R", "--rx-subdev-spec", type="subdev",
help="select USRP Rx side A or B", metavar="SUBDEV")
parser.add_option("-c", "--calibration", type="eng_float", default=0.0,
help="set frequency offset to Hz", metavar="Hz")
parser.add_option("-g", "--gain", type="int", default=None,
help="set RF gain", metavar="dB")
parser.add_option("-l", "--log", action="store_true", default=False,
help="log flowgraph to files (LOTS of data)")
parser.add_option("-v", "--verbose", action="store_true", default=False,
help="display debug output")
parser.add_option("-F", "--from-file", default=None,
help="read samples from file instead of USRP")
(options, args) = parser.parse_args()
if len(args) > 0 or (options.frequency == None and options.from_file == None):
print "Run 'usrp_flex.py -h' for options."
sys.exit(1)
if options.frequency == None:
options.frequency = 0.0
# Flow graph emits pages into message queue
queue = gr.msg_queue()
tb = app_top_block(options, queue)
runner = pager.queue_runner(queue)
try:
tb.run()
except KeyboardInterrupt:
pass
runner.end()
if __name__ == "__main__":
main()
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