1 #!/usr/bin/env /usr/bin/python
3 # Copyright 2004 Free Software Foundation, Inc.
5 # This file is part of GNU Radio
7 # GNU Radio is free software; you can redistribute it and/or modify
8 # it under the terms of the GNU General Public License as published by
9 # the Free Software Foundation; either version 3, or (at your option)
12 # GNU Radio is distributed in the hope that it will be useful,
13 # but WITHOUT ANY WARRANTY; without even the implied warranty of
14 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 # GNU General Public License for more details.
17 # You should have received a copy of the GNU General Public License
18 # along with GNU Radio; see the file COPYING. If not, write to
19 # the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
20 # Boston, MA 02111-1307, USA.
22 # This module upconverts the 19.2e6 sample rate signal from a center
23 # of 0 to 5.75e6 and converts to float, to prepare the signal for
24 # the old gnuradio 0.9 block (bit timing loop, field sync checker,
25 # equalizer and field sync demux), effectively simulating an
26 # mc4020 card, except the sample rate is 19.2e6 instead of 20e6.
28 # The signal is then centered on 5.75e6 with edges at 5.75 + 3.2 = 8.95MHz
29 # and 5.75 - 3.2 = 2.55Mhz, low pass filtered with cutoff at 9Mhz and a
30 # transition band width of 1Mhz.
32 # Input complex -3.2 to 3.2Mhz, output float 2.55 to 8.95Mhz.
34 from gnuradio import gr
37 sampling_freq = 19200000
41 src0 = gr.file_source (gr.sizeof_gr_complex,"/tmp/atsc_pipe_1")
43 duc_coeffs = gr.firdes.low_pass ( 1, 19.2e6, 9e6, 1e6, gr.firdes.WIN_HAMMING )
44 duc = gr.freq_xlating_fir_filter_ccf ( 1, duc_coeffs, 5.75e6, 19.2e6 )
46 c2f = gr.complex_to_float()
47 file = gr.file_sink(gr.sizeof_float,"/tmp/atsc_pipe_2")
49 fg.connect( src0, duc, c2f, file )
53 if __name__ == '__main__':