1 files changed, 128 insertions, 0 deletions
diff --git a/gr-blocks/lib/peak_detector_impl.cc b/gr-blocks/lib/peak_detector_impl.cc
new file mode 100644
index 0000000000..cda1f6007b
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+++ b/gr-blocks/lib/peak_detector_impl.cc
@@ -0,0 +1,128 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2007,2010,2013,2018 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 "peak_detector_impl.h"
+#include <gnuradio/io_signature.h>
+#include <string.h>
+#include <limits>
+
+namespace gr {
+  namespace blocks {
+
+    template <class T>
+    typename peak_detector<T>::sptr
+    peak_detector<T>::make(float threshold_factor_rise,
+                 float threshold_factor_fall,
+                 int look_ahead, float alpha)
+    {
+      return gnuradio::get_initial_sptr
+        (new peak_detector_impl<T>(threshold_factor_rise,
+                         threshold_factor_fall,
+                         look_ahead, alpha));
+    }
+
+    template <class T>
+    peak_detector_impl<T>::peak_detector_impl(float threshold_factor_rise,
+                             float threshold_factor_fall,
+                             int look_ahead, float alpha)
+    : sync_block("peak_detector",
+                    io_signature::make(1, 1, sizeof(T)),
+                    io_signature::make(1, 1, sizeof(char))),
+      d_threshold_factor_rise(threshold_factor_rise),
+      d_threshold_factor_fall(threshold_factor_fall),
+      d_look_ahead(look_ahead), d_avg_alpha(alpha), d_avg(0)
+    {
+    }
+
+    template <class T>
+    peak_detector_impl<T>::~peak_detector_impl()
+    {
+    }
+
+    template <class T>
+    int
+    peak_detector_impl<T>::work(int noutput_items,
+                      gr_vector_const_void_star &input_items,
+                      gr_vector_void_star &output_items)
+    {
+      T *iptr = (T*)input_items[0];
+      char *optr = (char*)output_items[0];
+
+      memset(optr, 0, noutput_items*sizeof(char));
+
+      T peak_val = std::numeric_limits<T>::min();
+      int peak_ind = 0;
+      unsigned char state = 0;
+      int i = 0;
+
+      //printf("noutput_items %d\n",noutput_items);
+      while(i < noutput_items) {
+        if(state == 0) {  // below threshold
+          if(iptr[i] > d_avg*d_threshold_factor_rise) {
+            state = 1;
+          }
+          else {
+            d_avg = (d_avg_alpha)*iptr[i] + (1-d_avg_alpha)*d_avg;
+            i++;
+          }
+        }
+        else if(state == 1) {  // above threshold, have not found peak
+          //printf("Entered State 1: %f  i: %d  noutput_items: %d\n", iptr[i], i, noutput_items);
+          if(iptr[i] > peak_val) {
+            peak_val = iptr[i];
+            peak_ind = i;
+            d_avg = (d_avg_alpha)*iptr[i] + (1-d_avg_alpha)*d_avg;
+            i++;
+          }
+          else if(iptr[i] > d_avg*d_threshold_factor_fall) {
+            d_avg = (d_avg_alpha)*iptr[i] + (1-d_avg_alpha)*d_avg;
+            i++;
+          }
+          else {
+            optr[peak_ind] = 1;
+            state = 0;
+            peak_val = -(T)INFINITY;
+            //printf("Leaving  State 1: Peak: %f  Peak Ind: %d   i: %d  noutput_items: %d\n",
+            //peak_val, peak_ind, i, noutput_items);
+          }
+        }
+      }
+
+      if(state == 0) {
+        //printf("Leave in State 0, produced %d\n",noutput_items);
+        return noutput_items;
+      }
+      else {   // only return up to passing the threshold
+        //printf("Leave in State 1, only produced %d of %d\n",peak_ind,noutput_items);
+        return peak_ind+1;
+      }
+    }
+
+    template class peak_detector<float>;
+    template class peak_detector<std::int16_t>;
+    template class peak_detector<std::int32_t>;
+  } /* namespace blocks */
+} /* namespace gr */