From 3d38e82e7d87dfc01132b199e33b53add8a706fa Mon Sep 17 00:00:00 2001
From: Tom Rondeau <trondeau@vt.edu>
Date: Fri, 15 Mar 2013 20:49:05 -0400
Subject: atsc: adjustments to atsc to start to conform to v3.7 structure.
Not going to comply completely with the new structure; just wanted to get it so that it looked more consistent once installed.
---
gr-atsc/python/all_atsc.py | 142 +++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 142 insertions(+)
create mode 100644 gr-atsc/python/all_atsc.py
(limited to 'gr-atsc/python/all_atsc.py')
diff --git a/gr-atsc/python/all_atsc.py b/gr-atsc/python/all_atsc.py
new file mode 100644
index 0000000000..7cac785149
--- /dev/null
+++ b/gr-atsc/python/all_atsc.py
@@ -0,0 +1,142 @@
+#!/usr/bin/env /usr/bin/python
+#
+# Copyright 2004 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 2, 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., 59 Temple Place - Suite 330,
+# Boston, MA 02111-1307, USA.
+#
+# This module starts the atsc processing chain taking the captured
+# off-air signal created with:
+#
+# uhd_rx_cfile.py --samp-rate=6.4e6
+# -f <center of tv signal channel freq>
+# -g <appropriate gain for best signal / noise>
+# -s output shorts
+#
+# All this module does is multiply the sample rate by 3, from 6.4e6 to
+# 19.2e6 complex samples / sec, then lowpass filter with a cutoff of 3.2MHz
+# and a transition band width of .5MHz. Center of the tv channels is
+# then at 0 with edges at -3.2MHz and 3.2MHz.
+
+from gnuradio import gr, atsc
+from gnuradio import filter
+from gnuradio import blocks
+import sys, os, math
+
+def graph (args):
+
+ nargs = len(args)
+ if nargs == 2:
+ infile = args[0]
+ outfile = args[1]
+ else:
+ raise ValueError('usage: interp.py input_file output_file\n')
+
+ tb = gr.top_block ()
+
+ # Convert to a from shorts to a stream of complex numbers.
+ srcf = blocks.file_source (gr.sizeof_short,infile)
+ s2ss = blocks.stream_to_streams(gr.sizeof_short,2)
+ s2f1 = blocks.short_to_float()
+ s2f2 = blocks.short_to_float()
+ src0 = blocks.float_to_complex()
+ tb.connect(srcf, s2ss)
+ tb.connect((s2ss, 0), s2f1, (src0, 0))
+ tb.connect((s2ss, 1), s2f2, (src0, 1))
+
+ # Low pass filter it and increase sample rate by a factor of 3.
+ lp_coeffs = filter.firdes.low_pass ( 3, 19.2e6, 3.2e6, .5e6, filter.firdes.WIN_HAMMING )
+ lp = filter.interp_fir_filter_ccf ( 3, lp_coeffs )
+ tb.connect(src0, lp)
+
+ # Upconvert it.
+ duc_coeffs = filter.firdes.low_pass ( 1, 19.2e6, 9e6, 1e6, filter.firdes.WIN_HAMMING )
+ duc = filter.freq_xlating_fir_filter_ccf ( 1, duc_coeffs, 5.75e6, 19.2e6 )
+ # Discard the imaginary component.
+ c2f = blocks.complex_to_float()
+ tb.connect(lp, duc, c2f)
+
+ # Frequency Phase Lock Loop
+ input_rate = 19.2e6
+ IF_freq = 5.75e6
+ # 1/2 as wide because we're designing lp filter
+ symbol_rate = atsc.ATSC_SYMBOL_RATE/2.
+ NTAPS = 279
+ tt = filter.firdes.root_raised_cosine (1.0, input_rate, symbol_rate, .115, NTAPS)
+ # heterodyne the low pass coefficients up to the specified bandpass
+ # center frequency. Note that when we do this, the filter bandwidth
+ # is effectively twice the low pass (2.69 * 2 = 5.38) and hence
+ # matches the diagram in the ATSC spec.
+ arg = 2. * math.pi * IF_freq / input_rate
+ t=[]
+ for i in range(len(tt)):
+ t += [tt[i] * 2. * math.cos(arg * i)]
+ rrc = filter.fir_filter_fff(1, t)
+
+ fpll = atsc.fpll()
+
+ pilot_freq = IF_freq - 3e6 + 0.31e6
+ lower_edge = 6e6 - 0.31e6
+ upper_edge = IF_freq - 3e6 + pilot_freq
+ transition_width = upper_edge - lower_edge
+ lp_coeffs = filter.firdes.low_pass(1.0,
+ input_rate,
+ (lower_edge + upper_edge) * 0.5,
+ transition_width,
+ filter.firdes.WIN_HAMMING);
+
+ lp_filter = filter.fir_filter_fff(1,lp_coeffs)
+
+ alpha = 1e-5
+ iir = filter.single_pole_iir_filter_ff(alpha)
+ remove_dc = blocks.sub_ff()
+
+ tb.connect(c2f, fpll, lp_filter)
+ tb.connect(lp_filter, iir)
+ tb.connect(lp_filter, (remove_dc,0))
+ tb.connect(iir, (remove_dc,1))
+
+ # Bit Timing Loop, Field Sync Checker and Equalizer
+
+ btl = atsc.bit_timing_loop()
+ fsc = atsc.fs_checker()
+ eq = atsc.equalizer()
+ fsd = atsc.field_sync_demux()
+
+ tb.connect(remove_dc, btl)
+ tb.connect((btl, 0),(fsc, 0),(eq, 0),(fsd, 0))
+ tb.connect((btl, 1),(fsc, 1),(eq, 1),(fsd, 1))
+
+ # Viterbi
+
+ viterbi = atsc.viterbi_decoder()
+ deinter = atsc.deinterleaver()
+ rs_dec = atsc.rs_decoder()
+ derand = atsc.derandomizer()
+ depad = atsc.depad()
+ dst = blocks.file_sink(gr.sizeof_char, outfile)
+ tb.connect(fsd, viterbi, deinter, rs_dec, derand, depad, dst)
+
+ dst2 = blocks.file_sink(gr.sizeof_gr_complex, "atsc_complex.data")
+ tb.connect(src0, dst2)
+
+ tb.run ()
+
+if __name__ == '__main__':
+ graph (sys.argv[1:])
+
+
--
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