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#!/usr/bin/env python
from gnuradio import gr, gru, eng_notation, optfir
from gnuradio import audio
from gnuradio import usrp
from gnuradio import blks
from gnuradio.eng_option import eng_option
from optparse import OptionParser
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.BASIC_RX))
class wfm_rx_graph (gr.flow_graph):
def __init__(self):
gr.flow_graph.__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("", "--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")
(options, args) = parser.parse_args()
if len(args) != 0:
parser.print_help()
sys.exit(1)
if abs(options.f1) < 1e6:
options.f1 *= 1e6
if abs(options.f2) < 1e6:
options.f2 *= 1e6
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"
# build graph
self.u = usrp.source_c(0, nchan=2) # 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)
mv = usrp.determine_rx_mux_value(self.u, options.rx_subdev_spec)
mv |= (mv << 8) & 0xff00 # both DDC inputs setup same way
self.u.set_mux(mv)
self.subdev = usrp.selected_subdev(self.u, options.rx_subdev_spec)
print "Using RX d'board %s" % (self.subdev.side_and_name(),)
# deinterleave two channels from FPGA
di = gr.deinterleave(gr.sizeof_gr_complex)
# wire up the head of the chain
self.connect(self.u, di)
# sound card as final sink
audio_sink = audio.sink(int(audio_rate), options.audio_output)
# taps for channel filter
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)
mid_freq = (f[0] + f[1]) / 2
# set front end PLL to middle frequency
ok, baseband_freq = self.subdev.set_freq(mid_freq)
for n in range(2):
chan_filt = gr.fir_filter_ccf (chanfilt_decim, chan_filt_coeffs)
guts = blks.wfm_rcv (self, demod_rate, audio_decimation)
volume_control = gr.multiply_const_ff(self.vol)
self.connect((di, n), chan_filt)
self.connect(chan_filt, guts, volume_control)
self.connect(volume_control, (audio_sink, n))
dxc_freq, inverted = usrp.calc_dxc_freq(f[n], baseband_freq,
self.u.converter_rate())
self.u.set_rx_freq(n, dxc_freq)
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
# set initial values
self.set_gain(options.gain)
def set_vol (self, vol):
self.vol = vol
self.volume_control.set_k(self.vol)
def set_gain(self, gain):
self.subdev.set_gain(gain)
if __name__ == '__main__':
fg = wfm_rx_graph()
try:
fg.run()
except KeyboardInterrupt:
pass
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