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#!/usr/bin/env python
#
# Copyright 2005-2007,2011 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, optfir, audio, blks2, uhd
from gnuradio.eng_option import eng_option
from optparse import OptionParser
import sys
import math
class wfm_rx_block (gr.top_block):
def __init__(self):
gr.top_block.__init__(self)
parser=OptionParser(option_class=eng_option)
parser.add_option("-a", "--args", type="string", default="",
help="UHD device address args [default=%default]")
parser.add_option("", "--spec", type="string", default="A:0 A:0",
help="Subdevice of UHD device where appropriate")
parser.add_option("-A", "--antenna", type="string", default=None,
help="select Rx Antenna where appropriate")
parser.add_option("", "--f1", type="eng_float", default=100.7e6,
help="set 1st station frequency to FREQ", metavar="FREQ")
parser.add_option("", "--f2", type="eng_float", default=102.5e6,
help="set 2nd station freq to FREQ", metavar="FREQ")
parser.add_option("-g", "--gain", type="eng_float", default=40,
help="set gain in dB (default is midpoint)")
parser.add_option("-O", "--audio-output", type="string", default="",
help="pcm device name. E.g., hw:0,0 or surround51 or /dev/dsp")
parser.add_option("", "--freq-min", type="eng_float", default=87.9e6,
help="Set a minimum frequency [default=%default]")
parser.add_option("", "--freq-max", type="eng_float", default=108.1e6,
help="Set a maximum frequency [default=%default]")
(options, args) = parser.parse_args()
if len(args) != 0:
parser.print_help()
sys.exit(1)
if abs(options.f1 - options.f2) > 5.5e6:
print "Sorry, two stations must be within 5.5MHz of each other"
raise SystemExit
f = (options.f1, options.f2)
self.vol = .1
self.state = "FREQ"
self.fm_freq_min = options.freq_min
self.fm_freq_max = options.freq_max
# build graph
stream_args = uhd.stream_args('fc32', channels=range(2))
self.u = uhd.usrp_source(device_addr=options.args, stream_args=stream_args)
# Set front end channel mapping
self.u.set_subdev_spec(options.spec)
usrp_rate = 320e3
demod_rate = 320e3
audio_rate = 32e3
audio_decim = int(demod_rate / audio_rate)
self.u.set_samp_rate(usrp_rate)
dev_rate = self.u.get_samp_rate()
# Make sure dboard can suppor the required frequencies
frange = self.u.get_freq_range()
if(frange.start() > self.fm_freq_max or frange.stop() < self.fm_freq_min):
sys.stderr.write("Radio does not support required frequency range.\n")
sys.exit(1)
# sound card as final sink
self.audio_sink = audio.sink(int(audio_rate), options.audio_output)
# taps for channel filter
nfilts = 32
chan_coeffs = optfir.low_pass (nfilts, # gain
nfilts*usrp_rate, # sampling rate
80e3, # passband cutoff
115e3, # stopband cutoff
0.1, # passband ripple
60) # stopband attenuation
rrate = usrp_rate / dev_rate
# set front end PLL to middle frequency
mid_freq = (f[0] + f[1]) / 2.0
if options.gain is None:
# if no gain was specified, use the mid-point in dB
g = self.u.get_gain_range()
options.gain = float(g.start()+g.stop())/2.0
for n in range(2):
chan_filt = blks2.pfb_arb_resampler_ccf(rrate, chan_coeffs, nfilts)
guts = blks2.wfm_rcv (demod_rate, audio_decim)
volume_control = gr.multiply_const_ff(self.vol)
#self.connect((self.di, n), chan_filt)
self.connect((self.u, n), chan_filt)
self.connect(chan_filt, guts, volume_control)
self.connect(volume_control, (self.audio_sink, n))
# Test the the requested frequencies are in range
if(f[n] < self.fm_freq_min or f[n] > self.fm_freq_max):
sys.stderr.write("Requested frequency is outside of required frequency range.\n")
sys.exit(1)
# Tune each channel by setting the RF freq to mid_freq and the
# DDC freq to f[n].
tr = uhd.tune_request(f[n], rf_freq=mid_freq,
rf_freq_policy=uhd.tune_request.POLICY_MANUAL)
self.u.set_center_freq(tr, n)
# Set gain for each channel
self.set_gain(options.gain, n)
# Set the antenna
if(options.antenna):
self.u.set_antenna(options.antenna, n)
def set_vol (self, vol):
self.vol = vol
self.volume_control.set_k(self.vol)
def set_gain(self, gain, n):
self.u.set_gain(gain, n)
if __name__ == '__main__':
tb = wfm_rx_block()
try:
tb.run()
except KeyboardInterrupt:
pass
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