1 files changed, 102 insertions, 0 deletions
diff --git a/gr-digital/lib/simple_correlator_impl.h b/gr-digital/lib/simple_correlator_impl.h
new file mode 100644
index 0000000000..fe324131fd
--- /dev/null
+++ b/gr-digital/lib/simple_correlator_impl.h
@@ -0,0 +1,102 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2004,2013 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.
+ */
+
+#ifndef INCLUDED_GR_SIMPLE_CORRELATOR_IMPL_H
+#define INCLUDED_GR_SIMPLE_CORRELATOR_IMPL_H
+
+#include <digital/simple_correlator.h>
+
+//#define	DEBUG_SIMPLE_CORRELATOR
+
+namespace gr {
+  namespace digital {
+    
+    class simple_correlator_impl : public simple_correlator
+    {
+    private:
+      static const int OVERSAMPLE = 8;
+      enum state_t { ST_LOOKING, ST_UNDER_THRESHOLD, ST_LOCKED };
+
+      int            d_payload_bytesize;
+      state_t        d_state;
+      unsigned int   d_osi;			// over sample index [0,OVERSAMPLE-1]
+      unsigned int   d_transition_osi;		// first index where Hamming dist < thresh
+      unsigned int   d_center_osi;		// center of bit
+      unsigned long long int d_shift_reg[OVERSAMPLE];
+      int            d_bblen;			// length of bitbuf
+      unsigned char *d_bitbuf;			// demodulated bits
+      unsigned char *d_pktbuf;			// temp packet buf
+      int            d_bbi;			// bitbuf index
+
+      static const int AVG_PERIOD = 512;	// must be power of 2 (for freq offset correction)
+      int   d_avbi;
+      float d_avgbuf[AVG_PERIOD];
+      float d_avg;
+      float d_accum;
+
+#ifdef DEBUG_SIMPLE_CORRELATOR
+      FILE *d_debug_fp;    // binary log file
+#endif
+
+      inline int slice (float x)
+      {
+        return x >= d_avg ? 1 : 0;
+      }
+
+      void update_avg(float x);
+
+      void enter_locked ();
+      void enter_under_threshold ();
+      void enter_looking ();
+
+      static int add_index (int a, int b)
+      {
+        int t = a + b;
+        if(t >= OVERSAMPLE)
+          t -= OVERSAMPLE;
+        assert(t >= 0 && t < OVERSAMPLE);
+        return t;
+      }
+
+      static int sub_index (int a, int b)
+      {
+        int t = a - b;
+        if(t < 0)
+          t += OVERSAMPLE;
+        assert(t >= 0 && t < OVERSAMPLE);
+        return t;
+      }
+
+    public:
+      simple_correlator_impl(int payload_bytesize);
+      ~simple_correlator_impl();
+
+      int general_work(int noutput_items,
+                       gr_vector_int &ninput_items,
+                       gr_vector_const_void_star &input_items,
+                       gr_vector_void_star &output_items);
+    };
+
+  } /* namespace digital */
+} /* namespace gr */
+
+#endif /* INCLUDED_GR_SIMPLE_CORRELATOR_IMPL_H */