1 files changed, 183 insertions, 0 deletions
diff --git a/gr-dtv/lib/atsc/atsc_equalizer_impl.cc b/gr-dtv/lib/atsc/atsc_equalizer_impl.cc
new file mode 100644
index 0000000000..c804be6dc7
--- /dev/null
+++ b/gr-dtv/lib/atsc/atsc_equalizer_impl.cc
@@ -0,0 +1,183 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2014 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_equalizer_impl.h"
+#include "atsc_types.h"
+#include "atsc_pnXXX_impl.h"
+#include <gnuradio/io_signature.h>
+
+namespace gr {
+  namespace dtv {
+
+    atsc_equalizer::sptr
+    atsc_equalizer::make()
+    {
+      return gnuradio::get_initial_sptr
+	(new atsc_equalizer_impl());
+    }
+
+    static float
+    bin_map (int bit)
+    {
+      return bit ? +5 : -5;
+    }
+
+    static void
+    init_field_sync_common (float *p, int mask)
+    {
+      int i = 0;
+
+      p[i++] = bin_map (1);			// data segment sync pulse
+      p[i++] = bin_map (0);
+      p[i++] = bin_map (0);
+      p[i++] = bin_map (1);
+
+      for (int j = 0; j < 511; j++)		// PN511
+        p[i++] = bin_map (atsc_pn511[j]);
+
+      for (int j = 0; j < 63; j++)		// PN63
+        p[i++] = bin_map (atsc_pn63[j]);
+
+      for (int j = 0; j < 63; j++)		// PN63, toggled on field 2
+        p[i++] = bin_map (atsc_pn63[j] ^ mask);
+
+      for (int j = 0; j < 63; j++)		// PN63
+        p[i++] = bin_map (atsc_pn63[j]);
+    }
+
+    atsc_equalizer_impl::atsc_equalizer_impl()
+      : gr::block("dtv_atsc_equalizer",
+                  io_signature::make(1, 1, sizeof(atsc_soft_data_segment)),
+                  io_signature::make(1, 1, sizeof(atsc_soft_data_segment)))
+    {
+      init_field_sync_common(training_sequence1, 0);
+      init_field_sync_common(training_sequence2, 1);
+
+      for (int i = 0; i < NTAPS; i++)
+        d_taps[i] = 0.0;
+
+      d_buff_not_filled = true;
+    }
+
+    atsc_equalizer_impl::~atsc_equalizer_impl()
+    {
+    }
+
+    void
+    atsc_equalizer_impl::filterN(const float *input_samples, float *output_samples, int nsamples)
+    {
+      for (int j = 0; j < nsamples; j++) {
+        output_samples[j] = 0;
+        for(int i = 0; i < NTAPS; i++)
+          output_samples[j] += d_taps[i] * input_samples[j + i];
+      }
+    }
+
+    void
+    atsc_equalizer_impl::adaptN(const float *input_samples,
+                                const float *training_pattern,
+                                float *output_samples,
+                                int    nsamples)
+    {
+      static const double BETA = 0.00005;	// FIXME figure out what this ought to be
+	                                        // FIXME add gear-shifting
+
+      for(int j = 0; j < nsamples; j++) {
+        output_samples[j] = 0;
+        for( int i = 0; i < NTAPS; i++ )
+          output_samples[j] += d_taps[i] * input_samples[j + i];
+
+        double e = output_samples[j] - training_pattern[j];
+
+        // update taps...
+        for( int i = 0; i < NTAPS; i++ )
+          d_taps[i] -= BETA * e * (double)(input_samples[j + i]);
+      }
+    }
+
+    int
+    atsc_equalizer_impl::general_work(int noutput_items,
+                                      gr_vector_int &ninput_items,
+                                      gr_vector_const_void_star &input_items,
+                                      gr_vector_void_star &output_items)
+    {
+      const atsc_soft_data_segment *in = (const atsc_soft_data_segment *) input_items[0];
+      atsc_soft_data_segment *out = (atsc_soft_data_segment *) output_items[0];
+
+      int output_produced = 0;
+      int i = 0;
+
+      if(d_buff_not_filled) {
+        for(int j = 0; j < ATSC_DATA_SEGMENT_LENGTH; j++)
+          data_mem[NPRETAPS + j] = in[i].data[j];
+        d_flags = in[i].pli._flags;
+        d_segno = in[i].pli._segno;
+        d_buff_not_filled = false;
+        i++;
+      }
+
+      for (; i < noutput_items; i++) {
+
+        for(int j = 0; j < NTAPS - NPRETAPS; j++)
+          data_mem[ATSC_DATA_SEGMENT_LENGTH + NPRETAPS + j] = in[i].data[j];
+
+        if(d_segno == -1) {
+          if(d_flags & 0x0010) {
+            adaptN(data_mem, training_sequence2, data_mem2, KNOWN_FIELD_SYNC_LENGTH);
+            //filterN(&data_mem[KNOWN_FIELD_SYNC_LENGTH], data_mem2, ATSC_DATA_SEGMENT_LENGTH - KNOWN_FIELD_SYNC_LENGTH);
+          }
+          else if( !(d_flags & 0x0010) ) {
+            adaptN( data_mem, training_sequence1, data_mem2, KNOWN_FIELD_SYNC_LENGTH );
+            //filterN(&data_mem[KNOWN_FIELD_SYNC_LENGTH], data_mem2, ATSC_DATA_SEGMENT_LENGTH - KNOWN_FIELD_SYNC_LENGTH);
+          }
+        }
+        else {
+          filterN(data_mem, data_mem2, ATSC_DATA_SEGMENT_LENGTH);
+
+          for(int j = 0; j < ATSC_DATA_SEGMENT_LENGTH; j++)
+            out[output_produced].data[j] = data_mem2[j];
+
+          out[output_produced].pli._flags = d_flags;
+          out[output_produced].pli._segno = d_segno;
+          output_produced++;
+        }
+
+        for( int j = 0; j < NPRETAPS; j++ )
+          data_mem[j] = data_mem[ATSC_DATA_SEGMENT_LENGTH + j];
+
+        for(int j = 0; j < ATSC_DATA_SEGMENT_LENGTH; j++)
+          data_mem[NPRETAPS + j] = in[i].data[j];
+
+        d_flags = in[i].pli._flags;
+        d_segno = in[i].pli._segno;
+      }
+
+      consume_each(noutput_items);
+      return output_produced;
+    }
+
+  } /* namespace dtv */
+} /* namespace gr */