ber_bf.h

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/* -*- c++ -*- */
/*
 * Copyright 2013-2014 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_FEC_BER_BF_H
#define INCLUDED_FEC_BER_BF_H

#include <gnuradio/block.h>
#include <gnuradio/fec/api.h>

namespace gr {
namespace fec {

/*!
 * \brief BER block in FECAPI
 * \ingroup error_coding_blk
 *
 * \details
 *
 * This block measures the bit error rate between two streams of
 * packed data. It compares the bits of each streams and counts
 * the number of incorrect bits between them. It outputs the log
 * of the bit error rate, so a value of -X is 10^{-X} bit errors.
 *
 * When the \p mode is set to false (default), it is in streaming
 * mode. This means that the output is constantly producing the
 * current value of the BER. In this mode, there is a single
 * output BER calculation per chunk of bytes passed to it, so
 * there is no exact timing between calculations of BER. In this
 * mode, the other two parameters to the constructor are ignored.
 *
 * When \p mode is true, the block is in test mode. This mode is
 * used in the ber_curve_gen example and for other offline
 * analysis of BER curves. Here, the block waits until at least \p
 * berminerrors are observed and then produces a BER
 * calculation. The parameter \p ber_limit helps make sure that
 * the simulation is controlled. If the BER calculation drops
 * below the \p ber_limit setting, the block will exit and simply
 * return the set limit; the real BER is therefore some amount
 * lower than this.
 *
 * Note that this block takes in data as packed bytes with 8-bits
 * per byte used. It outputs a stream of floats as the log-scale BER.
 */
class FEC_API ber_bf : virtual public block
{
public:
    // gr::fec::ber_bf::sptr
    typedef boost::shared_ptr<ber_bf> sptr;

    /*!
     * Get total number of errors counter value.
     */
    virtual long total_errors() = 0;

    /*!
     * Calculate the BER between two streams of data.
     *
     * \param test_mode false for normal streaming mode (default);
     *        true for test mode.
     * \param berminerrors the block needs to observe this many
     *        errors before outputting a result. Only valid when
     *        test_mode=true.
     * \param ber_limit if the BER calculation falls below this
     *        limit, produce this value and exit. Only valid when
     *        test_mode=true.
     */
    static sptr
    make(bool test_mode = false, int berminerrors = 100, float ber_limit = -7.0);
};

} /* namespace fec */
} /* namespace gr */

#endif /* INCLUDED_FEC_BER_BF_H */