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#!/usr/bin/env python
#
# 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, eng_notation, optfir
from gnuradio import audio
from gnuradio import usrp
from gnuradio import blks2
from gnuradio.eng_option import eng_option
from optparse import OptionParser
from usrpm import usrp_dbid
import sys
import math
def pick_subdevice(u):
"""
The user didn't specify a subdevice on the command line.
Try for one of these, in order: TV_RX, BASIC_RX, whatever is on side A.
@return a subdev_spec
"""
return usrp.pick_subdev(u, (usrp_dbid.TV_RX,
usrp_dbid.TV_RX_REV_2,
usrp_dbid.TV_RX_REV_3,
usrp_dbid.BASIC_RX))
class wfm_rx_block (gr.top_block):
def __init__(self):
gr.top_block.__init__(self)
parser=OptionParser(option_class=eng_option)
parser.add_option("-R", "--rx-subdev-spec", type="subdev", default=None,
help="select USRP Rx side A or B (default=A)")
parser.add_option("-f", "--freq", type="eng_float", default=100.1e6,
help="set frequency to FREQ", metavar="FREQ")
parser.add_option("-g", "--gain", type="eng_float", default=None,
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")
(options, args) = parser.parse_args()
if len(args) != 0:
parser.print_help()
sys.exit(1)
self.vol = .1
self.state = "FREQ"
self.freq = 0
# build graph
self.u = usrp.source_c() # usrp is data source
adc_rate = self.u.adc_rate() # 64 MS/s
usrp_decim = 200
self.u.set_decim_rate(usrp_decim)
usrp_rate = adc_rate / usrp_decim # 320 kS/s
chanfilt_decim = 1
demod_rate = usrp_rate / chanfilt_decim
audio_decimation = 10
audio_rate = demod_rate / audio_decimation # 32 kHz
if options.rx_subdev_spec is None:
options.rx_subdev_spec = pick_subdevice(self.u)
self.u.set_mux(usrp.determine_rx_mux_value(self.u, options.rx_subdev_spec))
self.subdev = usrp.selected_subdev(self.u, options.rx_subdev_spec)
print "Using RX d'board %s" % (self.subdev.side_and_name(),)
chan_filt_coeffs = optfir.low_pass (1, # gain
usrp_rate, # sampling rate
80e3, # passband cutoff
115e3, # stopband cutoff
0.1, # passband ripple
60) # stopband attenuation
#print len(chan_filt_coeffs)
chan_filt = gr.fir_filter_ccf (chanfilt_decim, chan_filt_coeffs)
self.guts = blks2.wfm_rcv (demod_rate, audio_decimation)
self.volume_control = gr.multiply_const_ff(self.vol)
# sound card as final sink
audio_sink = audio.sink(int(audio_rate),
options.audio_output,
False) # ok_to_block
# now wire it all together
self.connect (self.u, chan_filt, self.guts, self.volume_control, audio_sink)
if options.gain is None:
# if no gain was specified, use the mid-point in dB
g = self.subdev.gain_range()
options.gain = float(g[0]+g[1])/2
if abs(options.freq) < 1e6:
options.freq *= 1e6
# set initial values
self.set_gain(options.gain)
if not(self.set_freq(options.freq)):
self._set_status_msg("Failed to set initial frequency")
def set_vol (self, vol):
self.vol = vol
self.volume_control.set_k(self.vol)
self.update_status_bar ()
def set_freq(self, target_freq):
"""
Set the center frequency we're interested in.
@param target_freq: frequency in Hz
@rypte: bool
Tuning is a two step process. First we ask the front-end to
tune as close to the desired frequency as it can. Then we use
the result of that operation and our target_frequency to
determine the value for the digital down converter.
"""
r = self.u.tune(0, self.subdev, target_freq)
if r:
self.freq = target_freq
self.update_status_bar()
self._set_status_msg("OK", 0)
return True
self._set_status_msg("Failed", 0)
return False
def set_gain(self, gain):
self.subdev.set_gain(gain)
def update_status_bar (self):
msg = "Freq: %s Volume:%f Setting:%s" % (
eng_notation.num_to_str(self.freq), self.vol, self.state)
self._set_status_msg(msg, 1)
def _set_status_msg(self, msg, which=0):
print msg
if __name__ == '__main__':
tb = wfm_rx_block()
try:
tb.run()
except KeyboardInterrupt:
pass
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