cma_equalizer_cc.h

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/* -*- c++ -*- */
/*
 * Copyright 2011,2012 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_DIGITAL_CMA_EQUALIZER_CC_H
#define INCLUDED_DIGITAL_CMA_EQUALIZER_CC_H

#include <gnuradio/digital/api.h>
#include <gnuradio/sync_decimator.h>

namespace gr {
namespace digital {

/*!
 * \brief Implements constant modulus adaptive filter on complex stream.
 * \ingroup equalizers_blk
 *
 * \details
 * The error value and tap update equations (for p=2) can be found in:
 *
 * D. Godard, "Self-Recovering Equalization and Carrier Tracking
 * in Two-Dimensional Data Communication Systems," IEEE
 * Transactions on Communications, Vol. 28, No. 11, pp. 1867 -
 * 1875, 1980.
 */
class DIGITAL_API cma_equalizer_cc : virtual public sync_decimator
{
protected:
    virtual gr_complex error(const gr_complex& out) = 0;
    virtual void update_tap(gr_complex& tap, const gr_complex& in) = 0;

public:
    // gr::digital::cma_equalizer_cc::sptr
    typedef boost::shared_ptr<cma_equalizer_cc> sptr;

    /*!
     * Make a CMA Equalizer block
     *
     * \param num_taps Numer of taps in the equalizer (channel size)
     * \param modulus Modulus of the modulated signals
     * \param mu Gain of the update loop
     * \param sps Number of samples per symbol of the input signal
     */
    static sptr make(int num_taps, float modulus, float mu, int sps);

    virtual void set_taps(const std::vector<gr_complex>& taps) = 0;
    virtual std::vector<gr_complex> taps() const = 0;
    virtual float gain() const = 0;
    virtual void set_gain(float mu) = 0;
    virtual float modulus() const = 0;
    virtual void set_modulus(float mod) = 0;
};

} /* namespace digital */
} /* namespace gr */

#endif /* INCLUDED_DIGITAL_CMA_EQUALIZER_CC_H */