mpsk_snr_est_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_MPSK_SNR_EST_CC_H
#define INCLUDED_DIGITAL_MPSK_SNR_EST_CC_H

#include <gnuradio/digital/api.h>
#include <gnuradio/digital/mpsk_snr_est.h>
#include <gnuradio/sync_block.h>

namespace gr {
  namespace digital {

    /*!
     * \brief A block for computing SNR of a signal.
     * \ingroup measurement_tools_blk
     *
     * \details
     * This block can be used to monitor and retrieve estimations of
     * the signal SNR. It is designed to work in a flowgraph and
     * passes all incoming data along to its output.
     *
     * The block is designed for use with M-PSK signals
     * especially. The type of estimator is specified as the \p type
     * parameter in the constructor. The estimators tend to trade off
     * performance for accuracy, although experimentation should be
     * done to figure out the right approach for a given
     * implementation. Further, the current set of estimators are
     * designed and proven theoretically under AWGN conditions; some
     * amount of error should be assumed and/or estimated for real
     * channel conditions.
     */
    class DIGITAL_API mpsk_snr_est_cc : virtual public sync_block
    {
    public:
      // gr::digital::mpsk_snr_est_cc::sptr
      typedef boost::shared_ptr<mpsk_snr_est_cc> sptr;

      /*! Factory function returning shared pointer of this class
       *
       *  \param type: the type of estimator to use gr::digital::snr_est_type_t
       *  "snr_est_type_t" for details about the available types
       *  \param tag_nsamples: after this many samples, a tag containing
       *  the SNR (key='snr') will be sent
       *  \param alpha: the update rate of internal running average
       *  calculations
       */
      static sptr make(snr_est_type_t type,
                       int tag_nsamples=10000,
                       double alpha=0.001);

      //! Return the estimated signal-to-noise ratio in decibels
      virtual double snr() = 0;

      //! Return the type of estimator in use
      virtual snr_est_type_t type() const = 0;

      //! Return how many samples between SNR tags
      virtual int tag_nsample() const = 0;

      //! Get the running-average coefficient
      virtual double alpha() const = 0;

      //! Set type of estimator to use
      virtual void set_type(snr_est_type_t t) = 0;

      //! Set the number of samples between SNR tags
      virtual void set_tag_nsample(int n) = 0;

      //! Set the running-average coefficient
      virtual void set_alpha(double alpha) = 0;
    };

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

#endif /* INCLUDED_DIGITAL_MPSK_SNR_EST_CC_H */