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authorTom Rondeau <trondeau@vt.edu>2013-03-18 17:41:12 -0400
committerTom Rondeau <trondeau@vt.edu>2013-03-18 17:41:12 -0400
commit644459b0c55987792df3a7b884ace1d0250231f1 (patch)
treeded5c662890dbccd28b8400aecfa5933600f9520 /gr-blocks/include
parent04682315bf151fb2c7c24673676cd8e07ab5fe2e (diff)
parente0236f2bf8eb4a069736d69808432348140e576f (diff)
Merge branch 'master' into next
Conflicts: gr-blocks/include/blocks/CMakeLists.txt gr-blocks/lib/CMakeLists.txt gr-blocks/swig/blocks_swig.i gr-digital/lib/digital_ofdm_sync_sc_cfb.cc
Diffstat (limited to 'gr-blocks/include')
-rw-r--r--gr-blocks/include/blocks/CMakeLists.txt1
-rw-r--r--gr-blocks/include/blocks/plateau_detector_fb.h71
2 files changed, 72 insertions, 0 deletions
diff --git a/gr-blocks/include/blocks/CMakeLists.txt b/gr-blocks/include/blocks/CMakeLists.txt
index a88eaeeb26..edad5ef526 100644
--- a/gr-blocks/include/blocks/CMakeLists.txt
+++ b/gr-blocks/include/blocks/CMakeLists.txt
@@ -165,6 +165,7 @@ install(FILES
pdu_to_tagged_stream.h
peak_detector2_fb.h
random_pdu.h
+ plateau_detector_fb.h
probe_rate.h
regenerate_bb.h
repack_bits_bb.h
diff --git a/gr-blocks/include/blocks/plateau_detector_fb.h b/gr-blocks/include/blocks/plateau_detector_fb.h
new file mode 100644
index 0000000000..041f9c1baf
--- /dev/null
+++ b/gr-blocks/include/blocks/plateau_detector_fb.h
@@ -0,0 +1,71 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2012-2013 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_BLOCKS_PLATEAU_DETECTOR_FB_H
+#define INCLUDED_BLOCKS_PLATEAU_DETECTOR_FB_H
+
+#include <blocks/api.h>
+#include <gr_sync_block.h>
+
+namespace gr {
+ namespace blocks {
+
+ /*!
+ * \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 level_blk
+ *
+ */
+ class BLOCKS_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 blocks
+} // namespace gr
+
+#endif /* INCLUDED_BLOCKS_PLATEAU_DETECTOR_FB_H */
+