1 files changed, 163 insertions, 0 deletions
diff --git a/gr-dtv/lib/dvbt/dvbt_map_impl.cc b/gr-dtv/lib/dvbt/dvbt_map_impl.cc
new file mode 100644
index 0000000000..05f6e7f69b
--- /dev/null
+++ b/gr-dtv/lib/dvbt/dvbt_map_impl.cc
@@ -0,0 +1,163 @@
+/* -*- c++ -*- */
+/* 
+ * Copyright 2015 Free Software Foundation, Inc.
+ * 
+ * This 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.
+ * 
+ * This software 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 this software; 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 <gnuradio/io_signature.h>
+#include <complex>
+#include "dvbt_map_impl.h"
+#include <stdio.h>
+#include <math.h>
+
+namespace gr {
+  namespace dtv {
+
+    dvbt_map::sptr
+    dvbt_map::make(int nsize, dvb_constellation_t constellation, dvbt_hierarchy_t hierarchy, dvbt_transmission_mode_t transmission, float gain)
+    {
+      return gnuradio::get_initial_sptr
+        (new dvbt_map_impl(nsize, constellation, hierarchy, transmission, gain));
+    }
+
+    /*
+     * The private constructor
+     */
+    dvbt_map_impl::dvbt_map_impl(int nsize, dvb_constellation_t constellation, dvbt_hierarchy_t hierarchy, dvbt_transmission_mode_t transmission, float gain)
+      : block("dvbt_map",
+          io_signature::make(1, 1, sizeof (unsigned char) * nsize),
+          io_signature::make(1, 1, sizeof (gr_complex) * nsize)),
+      config(constellation, hierarchy, gr::dtv::C1_2, gr::dtv::C1_2, gr::dtv::GI_1_32, transmission),
+      d_nsize(nsize),
+      d_constellation_size(0),
+      d_step(0),
+      d_alpha(0),
+      d_gain(0.0)
+    {
+      //Get parameters from config object
+      d_constellation_size = config.d_constellation_size;
+      d_transmission_mode = config.d_transmission_mode;
+      d_step = config.d_step;
+      d_alpha = config.d_alpha;
+      d_gain = gain * config.d_norm;
+
+      d_constellation_points = new gr_complex[d_constellation_size];
+      if (d_constellation_points == NULL) {
+        std::cout << "Cannot allocate memory for d_constellation_points" << std::endl;
+        exit(1);
+      }
+
+      make_constellation_points(d_constellation_size, d_step, d_alpha);
+    }
+
+    /*
+     * Our virtual destructor.
+     */
+    dvbt_map_impl::~dvbt_map_impl()
+    {
+      delete [] d_constellation_points;
+    }
+
+    unsigned int
+    dvbt_map_impl::bin_to_gray(unsigned int val)
+    {
+      return (val >> 1) ^ val;
+    }
+
+    void
+    dvbt_map_impl::make_constellation_points(int size, int step, int alpha)
+    {
+      // The symmetry of the constellation is used to calculate
+      // 16-QAM from QPSK and 64-QAM form 16-QAM
+
+      int bits_per_axis = log2(size) / 2;
+      int steps_per_axis = sqrt(size) / 2 - 1;
+
+      for (int i = 0; i < size; i++) {
+        // This is the quadrant made of the first two bits starting from MSB
+        int q = i >> (2 * (bits_per_axis - 1)) & 3;
+        // Sign for correctly calculate I and Q in each quadrant
+        int sign0 = (q >> 1) ? -1 : 1; int sign1 = (q & 1) ? -1 : 1;
+
+        int x = (i >> (bits_per_axis - 1)) & ((1 << (bits_per_axis - 1)) - 1);
+        int y = i & ((1 << (bits_per_axis - 1)) - 1);
+
+        int xval = alpha + (steps_per_axis - x) * step;
+        int yval = alpha + (steps_per_axis - y) * step;
+
+        int val = (bin_to_gray(x) << (bits_per_axis - 1)) + bin_to_gray(y);
+
+        // ETSI EN 300 744 Clause 4.3.5
+        // Actually the constellation is gray coded
+        // but the bits on each axis are not taken in consecutive order
+        // So we need to convert from b0b2b4b1b3b5->b0b1b2b3b4b5(QAM64)
+
+        x = 0; y = 0;
+
+        for (int j = 0; j < (bits_per_axis - 1); j++) {
+          x += ((val >> (1 + 2 * j)) & 1) << j;
+          y += ((val >> (2 * j)) & 1) << j;
+        }
+
+        val = (q << 2 * (bits_per_axis - 1)) + (x << (bits_per_axis - 1)) + y;
+
+        // Keep corresponding symbol bits->complex symbol in one vector
+        // Normalize the signal using gain
+        d_constellation_points[val] = d_gain * gr_complex(sign0 * xval, sign1 * yval);
+      }
+    }
+
+    gr_complex
+    dvbt_map_impl::find_constellation_point(int val)
+    {
+      return d_constellation_points[val];
+    }
+
+    void
+    dvbt_map_impl::forecast (int noutput_items, gr_vector_int &ninput_items_required)
+    {
+      ninput_items_required[0] = noutput_items;
+    }
+
+    int
+    dvbt_map_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 unsigned char *in = (const unsigned char *) input_items[0];
+      gr_complex *out = (gr_complex *) output_items[0];
+
+      for (int i = 0; i < (noutput_items * d_nsize); i++) {
+        out[i] = find_constellation_point(in[i]);
+      }
+
+      // Tell runtime system how many input items we consumed on
+      // each input stream.
+      consume_each (noutput_items);
+
+      // Tell runtime system how many output items we produced.
+      return noutput_items;
+    }
+
+  } /* namespace dtv */
+} /* namespace gr */
+