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#!/usr/bin/env python
#
# Copyright 2005,2006,2007 Free Software Foundation, Inc.
#
# This file is part of GNU Radio
#
# SPDX-License-Identifier: GPL-3.0-or-later
#
#
from gnuradio import gr, eng_notation, filter
from gnuradio import audio
from gnuradio import analog
from gnuradio import blocks
from gnuradio.eng_arg import eng_float, intx
from argparse import ArgumentParser
import sys
import math
class wfm_rx_block (gr.top_block):
def __init__(self):
gr.top_block.__init__(self)
parser = ArgumentParser(description="Decode WFM signal into WAV file.")
parser.add_argument("-V", "--volume", type=eng_float,
help="Volume (dB) <%r, %r> (default is midpoint)" %
self.volume_range()[:2])
parser.add_argument("input_file", help="Input file (complex samples)")
parser.add_argument("output_file", help="Output WAV file")
args = parser.parse_args()
self.vol = 0
# build graph
self.src = blocks.file_source(
gr.sizeof_gr_complex, args.input_file, False)
adc_rate = 64e6 # 64 MS/s
usrp_decim = 200
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
chan_filt_coeffs = filter.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 = filter.fir_filter_ccf(chanfilt_decim, chan_filt_coeffs)
#self.guts = analog.wfm_rcv (demod_rate, audio_decimation)
self.guts = analog.wfm_rcv_pll(demod_rate, audio_decimation)
# FIXME rework {add,multiply}_const_* to handle multiple streams
self.volume_control_l = blocks.multiply_const_ff(self.vol)
self.volume_control_r = blocks.multiply_const_ff(self.vol)
# wave file as final sink
if 1:
sink = blocks.wavfile_sink(args.output_file, 2, int(audio_rate),
blocks.FORMAT_WAV, blocks.FORMAT_PCM_16)
else:
sink = audio.sink(int(audio_rate),
args.audio_output,
False) # ok_to_block
# now wire it all together
self.connect(self.src, chan_filt, self.guts)
self.connect((self.guts, 0), self.volume_control_l, (sink, 0))
self.connect((self.guts, 1), self.volume_control_r, (sink, 1))
if args.volume is None:
g = self.volume_range()
args.volume = float(g[0] + g[1]) / 2
# set initial values
self.set_vol(args.volume)
def set_vol(self, vol):
g = self.volume_range()
self.vol = max(g[0], min(g[1], vol))
self.volume_control_l.set_k(10**(self.vol / 10))
self.volume_control_r.set_k(10**(self.vol / 10))
def volume_range(self):
return (-20.0, 0.0, 0.5)
if __name__ == '__main__':
tb = wfm_rx_block()
try:
tb.run()
except KeyboardInterrupt:
pass
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