GNU Radio 3.5.3.2 C++ API
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00001 /* -*- c++ -*- */ 00002 /* 00003 * Copyright 2011 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 #ifndef INCLUDED_DIGITAL_PROBE_MPSK_SNR_EST_C_H 00023 #define INCLUDED_DIGITAL_PROBE_MPSK_SNR_EST_C_H 00024 00025 #include <digital_api.h> 00026 #include <gr_sync_block.h> 00027 #include <digital_impl_mpsk_snr_est.h> 00028 00029 class digital_probe_mpsk_snr_est_c; 00030 typedef boost::shared_ptr<digital_probe_mpsk_snr_est_c> digital_probe_mpsk_snr_est_c_sptr; 00031 00032 DIGITAL_API digital_probe_mpsk_snr_est_c_sptr 00033 digital_make_probe_mpsk_snr_est_c(snr_est_type_t type, 00034 int msg_nsamples=10000, 00035 double alpha=0.001); 00036 00037 //! \brief A probe for computing SNR of a signal. 00038 /*! \ingroup snr_blk 00039 * 00040 * This is a probe block (a sink) that can be used to monitor and 00041 * retrieve estimations of the signal SNR. This probe is designed for 00042 * use with M-PSK signals especially. The type of estimator is 00043 * specified as the \p type parameter in the constructor. The 00044 * estimators tend to trade off performance for accuracy, although 00045 * experimentation should be done to figure out the right approach 00046 * for a given implementation. Further, the current set of estimators 00047 * are designed and proven theoretically under AWGN conditions; some 00048 * amount of error should be assumed and/or estimated for real 00049 * channel conditions. 00050 */ 00051 class DIGITAL_API digital_probe_mpsk_snr_est_c : public gr_sync_block 00052 { 00053 private: 00054 snr_est_type_t d_type; 00055 int d_nsamples, d_count; 00056 double d_alpha; 00057 digital_impl_mpsk_snr_est *d_snr_est; 00058 00059 //d_key is the message name, 'snr' 00060 pmt::pmt_t d_key; 00061 00062 /*! Factory function returning shared pointer of this class 00063 * 00064 * Parameters: 00065 * 00066 * \param type: the type of estimator to use \ref ref_snr_est_types 00067 * "snr_est_type_t" for details about the available types. 00068 * \param msg_nsamples: [not implemented yet] after this many 00069 * samples, a message containing the SNR (key='snr') will be sent 00070 * \param alpha: the update rate of internal running average 00071 * calculations. 00072 */ 00073 friend DIGITAL_API digital_probe_mpsk_snr_est_c_sptr 00074 digital_make_probe_mpsk_snr_est_c(snr_est_type_t type, 00075 int msg_nsamples, 00076 double alpha); 00077 00078 //! Private constructor 00079 digital_probe_mpsk_snr_est_c(snr_est_type_t type, 00080 int msg_nsamples, 00081 double alpha); 00082 00083 public: 00084 00085 ~digital_probe_mpsk_snr_est_c(); 00086 00087 int work (int noutput_items, 00088 gr_vector_const_void_star &input_items, 00089 gr_vector_void_star &output_items); 00090 00091 //! Return the estimated signal-to-noise ratio in decibels 00092 double snr(); 00093 00094 //! Return the type of estimator in use 00095 snr_est_type_t type() const; 00096 00097 //! Return how many samples between SNR messages 00098 int msg_nsample() const; 00099 00100 //! Get the running-average coefficient 00101 double alpha() const; 00102 00103 //! Set type of estimator to use 00104 void set_type(snr_est_type_t t); 00105 00106 //! Set the number of samples between SNR messages 00107 void set_msg_nsample(int n); 00108 00109 //! Set the running-average coefficient 00110 void set_alpha(double alpha); 00111 }; 00112 00113 #endif /* INCLUDED_DIGITAL_PROBE_MPSK_SNR_EST_C_H */