GNU Radio 3.7.1 C++ API
mpsk_snr_est_cc.h
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00001 /* -*- c++ -*- */
00002 /*
00003  * Copyright 2011,2012 Free Software Foundation, Inc.
00004  * 
00005  * This file is part of GNU Radio
00006  * 
00007  * GNU Radio is free software; you can redistribute it and/or modify
00008  * it under the terms of the GNU General Public License as published by
00009  * the Free Software Foundation; either version 3, or (at your option)
00010  * any later version.
00011  * 
00012  * GNU Radio is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00015  * GNU General Public License for more details.
00016  * 
00017  * You should have received a copy of the GNU General Public License
00018  * along with GNU Radio; see the file COPYING.  If not, write to
00019  * the Free Software Foundation, Inc., 51 Franklin Street,
00020  * Boston, MA 02110-1301, USA.
00021  */
00022 
00023 #ifndef INCLUDED_DIGITAL_MPSK_SNR_EST_CC_H
00024 #define INCLUDED_DIGITAL_MPSK_SNR_EST_CC_H
00025 
00026 #include <gnuradio/digital/api.h>
00027 #include <gnuradio/digital/mpsk_snr_est.h>
00028 #include <gnuradio/sync_block.h>
00029 
00030 namespace gr {
00031   namespace digital {
00032 
00033     /*!
00034      * \brief A block for computing SNR of a signal.
00035      * \ingroup measurement_tools_blk
00036      *
00037      * \details
00038      * This block can be used to monitor and retrieve estimations of
00039      * the signal SNR. It is designed to work in a flowgraph and
00040      * passes all incoming data along to its output.
00041      *
00042      * The block is designed for use with M-PSK signals
00043      * especially. The type of estimator is specified as the \p type
00044      * parameter in the constructor. The estimators tend to trade off
00045      * performance for accuracy, although experimentation should be
00046      * done to figure out the right approach for a given
00047      * implementation. Further, the current set of estimators are
00048      * designed and proven theoretically under AWGN conditions; some
00049      * amount of error should be assumed and/or estimated for real
00050      * channel conditions.
00051      */
00052     class DIGITAL_API mpsk_snr_est_cc : virtual public sync_block
00053     {
00054     public:
00055       // gr::digital::mpsk_snr_est_cc::sptr
00056       typedef boost::shared_ptr<mpsk_snr_est_cc> sptr;
00057 
00058       /*! Factory function returning shared pointer of this class
00059        *
00060        *  \param type: the type of estimator to use gr::digital::snr_est_type_t
00061        *  "snr_est_type_t" for details about the available types
00062        *  \param tag_nsamples: after this many samples, a tag containing
00063        *  the SNR (key='snr') will be sent
00064        *  \param alpha: the update rate of internal running average
00065        *  calculations
00066        */
00067       static sptr make(snr_est_type_t type,
00068                        int tag_nsamples=10000,
00069                        double alpha=0.001);
00070 
00071       //! Return the estimated signal-to-noise ratio in decibels
00072       virtual double snr() = 0;
00073 
00074       //! Return the type of estimator in use
00075       virtual snr_est_type_t type() const = 0;
00076 
00077       //! Return how many samples between SNR tags
00078       virtual int tag_nsample() const = 0;
00079 
00080       //! Get the running-average coefficient
00081       virtual double alpha() const = 0;
00082 
00083       //! Set type of estimator to use
00084       virtual void set_type(snr_est_type_t t) = 0;
00085 
00086       //! Set the number of samples between SNR tags
00087       virtual void set_tag_nsample(int n) = 0;
00088 
00089       //! Set the running-average coefficient
00090       virtual void set_alpha(double alpha) = 0;
00091     };
00092 
00093   } /* namespace digital */
00094 } /* namespace gr */
00095 
00096 #endif /* INCLUDED_DIGITAL_MPSK_SNR_EST_CC_H */