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# Copyright 2004 Free Software Foundation, Inc.
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# This file is part of GNU Radio
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# GNU Radio is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 3, or (at your option)
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# GNU Radio is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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# You should have received a copy of the GNU General Public License
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# along with GNU Radio; see the file COPYING. If not, write to
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# the Free Software Foundation, Inc., 51 Franklin Street,
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# Boston, MA 02110-1301, USA.
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# Demodulate an AM signal from the TVRX or a recorded file.
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# The file format must be 256 ksps, complex data.
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from gnuradio import gr, gru, eng_notation
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from gnuradio import audio_oss as audio
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from gnuradio import usrp
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from gnuradio import tv_rx
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from gnuradio.eng_option import eng_option
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from optparse import OptionParser
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from gnuradio.wxgui import stdgui, fftsink, scopesink
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# return a gr.flow_graph
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class wfm_rx_graph (stdgui.gui_flow_graph):
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def __init__(self,frame,panel,vbox,argv):
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stdgui.gui_flow_graph.__init__ (self,frame,panel,vbox,argv)
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# Decimation rate from USRP ADC to IF.
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# Calculate the sampling rate of the USRP and capture file.
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# Decimate the IF sampling rate down by 4 to 64 ksps
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# This is a flow graph that has an input (capture file) and output (audio channel).
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#self = gr.flow_graph ()
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# Signal source is assumed to be 256 kspb / complex data stream.
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src = usrp.source_c (0, usrp_decim, 1, gru.hexint(0xf0f0f0f0), 0)
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src = usrp.source_c (0, usrp_decim, 1, gru.hexint(0xf0f0f0f2), 0)
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if_rate = 640e3 # src.adc_freq() / usrp_decim
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demod_rate = if_rate / if_decim
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audio_rate = demod_rate / audio_decimation
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dboard = tv_rx.tv_rx (src, which_side)
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(success, actual_freq) = dboard.set_freq(rf_freq)
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if_freq = rf_freq - actual_freq
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src.set_rx_freq (0, -if_freq)
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print "actual freq ", actual_freq
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print "IF freq ", if_freq
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#src = gr.file_source (gr.sizeof_gr_complex, "samples/atis_ffz_am_baseband_256k_complex.dat")
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#src = gr.file_source (gr.sizeof_gr_complex, "samples/garagedoor1.dat", True)
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#channel_coeffs = gr.firdes.band_pass (
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# 10, # center of low transition band
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# 10000, # center of hi transition band
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# 200, # width of transition band
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# gr.firdes.WIN_HAMMING)
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channel_coeffs = gr.firdes.low_pass (1.0, if_rate, 10e3, 4e3, gr.firdes.WIN_HANN)
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print "len(channel_coeffs) = ", len(channel_coeffs)
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# Tune to the desired frequency.
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ddc = gr.freq_xlating_fir_filter_ccf (if_decim, channel_coeffs, -20e3, if_rate)
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# Demodule with classic sqrt (I*I + Q*Q)
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magblock = gr.complex_to_mag()
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volumecontrol = gr.multiply_const_ff(.1)
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audio_coeffs = gr.firdes.band_pass (
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10, # center of low transition band
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6000, # center of hi transition band
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200, # width of transition band
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gr.firdes.WIN_HAMMING)
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# Low pass filter the demodulator output
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#audio_coeffs = gr.firdes.low_pass (1.0, demod_rate, 500, 200, gr.firdes.WIN_HANN)
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print "len(audio_coeffs) = ", len(audio_coeffs)
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# input: float; output: float
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audio_filter = gr.fir_filter_fff (audio_decimation, audio_coeffs)
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# sound card as final sink
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audio_sink = audio.sink (int (audio_rate))
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# now wire it all together
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self.connect (src, ddc)
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self.connect (ddc, magblock)
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self.connect (magblock, volumecontrol)
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self.connect (volumecontrol, audio_filter)
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self.connect (audio_filter, (audio_sink, 0))
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d_win = fftsink.fft_sink_c (self, panel, title="RF", fft_size=512, sample_rate=if_rate)
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self.connect (src,d_win)
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vbox.Add (d_win.win, 4, wx.EXPAND)
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p_win = fftsink.fft_sink_c (self, panel, title="IF", fft_size=512, sample_rate=demod_rate)
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self.connect (ddc,p_win)
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vbox.Add (p_win.win, 4, wx.EXPAND)
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r_win = fftsink.fft_sink_f (self, panel, title="Audio", fft_size=512, sample_rate=audio_rate)
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self.connect (audio_filter,r_win)
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vbox.Add (r_win.win, 4, wx.EXPAND)
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#audio_oscope = scopesink.scope_sink_f (self, panel, "Oscope Data", audio_rate)
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#self.connect (audio_filter, audio_oscope)
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#vbox.Add (audio_oscope.win, 4, wx.EXPAND)
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if __name__ == '__main__':
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app = stdgui.stdapp (wfm_rx_graph, "TVRX AM RX")