2 files changed, 72 insertions, 2 deletions
diff --git a/gr-analog/include/analog/CMakeLists.txt b/gr-analog/include/analog/CMakeLists.txt
index b113dacc44..a44f119d36 100644
--- a/gr-analog/include/analog/CMakeLists.txt
+++ b/gr-analog/include/analog/CMakeLists.txt
@@ -105,8 +105,7 @@ install(FILES
     rail_ff.h
     rotator.h
     sig_source_waveform.h
-    simple_squelch_cc.h
-    DESTINATION ${GR_INCLUDE_DIR}/gnuradio/analog
+    simple_squelch_cc.h plateau_detector_fb.h DESTINATION ${GR_INCLUDE_DIR}/gnuradio/analog
     COMPONENT "analog_devel"
 )
 
diff --git a/gr-analog/include/analog/plateau_detector_fb.h b/gr-analog/include/analog/plateau_detector_fb.h
new file mode 100644
index 0000000000..33629bd18b
--- /dev/null
+++ b/gr-analog/include/analog/plateau_detector_fb.h
@@ -0,0 +1,71 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2012 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_ANALOG_PLATEAU_DETECTOR_FB_H
+#define INCLUDED_ANALOG_PLATEAU_DETECTOR_FB_H
+
+#include <analog/api.h>
+#include <gr_sync_block.h>
+
+namespace gr {
+  namespace analog {
+
+    /*!
+     * \brief Detects a plateau and marks the middle.
+     *
+     * Detect a plateau of a-priori known height. Input is a stream of floats,
+     * the output is a stream of bytes. Whenever a plateau is detected, the
+     * middle of that plateau is marked with a '1' on the output stream (all
+     * other samples are left at zero).
+     *
+     * You can use this in a Schmidl & Cox synchronisation algorithm to interpret
+     * the output of the normalized correlator. Just pass the length of the cyclic
+     * prefix (in samples) as the max_len parameter).
+     *
+     * Unlike the peak detectors, you must the now the absolute height of the plateau.
+     * Whenever the amplitude exceeds the given threshold, it starts assuming the
+     * presence of a plateau.
+     *
+     * An implicit hysteresis is provided by the fact that after detecting one plateau,
+     * it waits at least max_len samples before the next plateau can be detected.
+     *
+     * \ingroup analog
+     *
+     */
+    class ANALOG_API plateau_detector_fb : virtual public gr_sync_block
+    {
+    public:
+       typedef boost::shared_ptr<plateau_detector_fb> sptr;
+
+       /*!
+	* \param max_len Maximum length of the plateau
+	* \param threshold Anything above this value is considered a plateau
+	*/
+       static sptr make(int max_len, float threshold=0.9);
+    };
+
+  } // namespace analog
+} // namespace gr
+
+#endif /* INCLUDED_ANALOG_PLATEAU_DETECTOR_FB_H */
+