1 files changed, 125 insertions, 0 deletions
diff --git a/gr-atsc/lib/atsc_bit_timing_loop.cc b/gr-atsc/lib/atsc_bit_timing_loop.cc
new file mode 100644
index 0000000000..7287eee19f
--- /dev/null
+++ b/gr-atsc/lib/atsc_bit_timing_loop.cc
@@ -0,0 +1,125 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2006,2010 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 3, 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., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <atsc/bit_timing_loop.h>
+#include <gr_io_signature.h>
+#include <atsc/consts.h>
+#include <string.h>
+
+// Input rate changed from 20MHz to 19.2 to support usrp at 3 * 6.4MHz
+float input_rate = 19.2e6;
+double ratio_of_rx_clock_to_symbol_freq = input_rate / ATSC_SYMBOL_RATE;
+
+
+atsc_bit_timing_loop_sptr
+atsc_make_bit_timing_loop()
+{
+  return gnuradio::get_initial_sptr(new atsc_bit_timing_loop());
+}
+
+
+atsc_bit_timing_loop::atsc_bit_timing_loop()
+  : gr_block("atsc_bit_timing_loop",
+		  gr_make_io_signature(1, 1, sizeof(float)),
+             gr_make_io_signature3(2, 3, sizeof(float), sizeof(float), sizeof(float))),
+		  d_interp(ratio_of_rx_clock_to_symbol_freq), d_next_input(0),
+		  d_rx_clock_to_symbol_freq (ratio_of_rx_clock_to_symbol_freq),
+		  d_si(0)
+{
+  reset();
+}
+
+void
+atsc_bit_timing_loop::forecast (int noutput_items, gr_vector_int &ninput_items_required)
+{
+  unsigned ninputs = ninput_items_required.size();
+  for (unsigned i = 0; i < ninputs; i++)
+    ninput_items_required[i] = static_cast<int>(noutput_items * d_rx_clock_to_symbol_freq) + 1500 - 1;
+
+}
+
+int
+atsc_bit_timing_loop::general_work (int noutput_items,
+                                 gr_vector_int &ninput_items,
+                                 gr_vector_const_void_star &input_items,
+                                 gr_vector_void_star &output_items)
+{
+  int   r = work (noutput_items, input_items, output_items);
+  if (r > 0)
+    consume_each (d_si);
+  return r;
+}
+
+
+int
+atsc_bit_timing_loop::work (int noutput_items,
+		       gr_vector_const_void_star &input_items,
+		       gr_vector_void_star &output_items)
+{
+  const float *in = (const float *) input_items[0];
+  float *out_sample = (float *) output_items[0];
+  atsc::syminfo *out_tag = (atsc::syminfo *) output_items[1];
+  float *out_timing_error = (float *) output_items[2];
+
+  assert(sizeof(float) == sizeof(atsc::syminfo));
+
+  // We are tasked with producing output.size output samples.
+  // We will consume approximately 2 * output.size input samples.
+
+  int  k;              // output index
+
+  float         interp_sample;
+  int           symbol_index;
+  double        timing_adjustment = 0;
+  bool          seg_locked;
+  atsc::syminfo    tag;
+  // ammount requested in forecast
+  unsigned long input_size = noutput_items * d_rx_clock_to_symbol_freq + 1500 -1;
+
+  memset (&tag, 0, sizeof (tag));
+
+  // ammount actually consumed
+  d_si = 0;
+
+  for (k = 0; k < noutput_items; k++){
+    if (!d_interp.update (in, input_size, &d_si, timing_adjustment, &interp_sample)){
+      fprintf (stderr, "GrAtscBitTimingLoop3: ran short on data...\n");
+      break;
+    }
+
+    d_sssr.update (interp_sample, &seg_locked, &symbol_index, &timing_adjustment);
+    if (output_items.size() == 3) {
+      out_timing_error[k] = timing_adjustment;
+    }
+    out_sample[k] = interp_sample;
+    tag.valid = seg_locked;
+    tag.symbol_num = symbol_index;
+    out_tag[k] = tag;
+
+  }
+  
+  return k;
+}