GNU Radio C++ API
gr_probe_mpsk_snr_c.h
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/* -*- c++ -*- */
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/*
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* Copyright 2008 Free Software Foundation, Inc.
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*
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* This file is part of GNU Radio
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*
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* GNU Radio is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 3, or (at your option)
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* any later version.
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*
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* GNU Radio is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GNU Radio; see the file COPYING. If not, write to
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* the Free Software Foundation, Inc., 51 Franklin Street,
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* Boston, MA 02110-1301, USA.
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*/
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#ifndef INCLUDED_GR_PROBE_MPSK_SNR_C_H
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#define INCLUDED_GR_PROBE_MPSK_SNR_C_H
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#include <
gr_core_api.h
>
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#include <
gr_sync_block.h
>
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class
gr_probe_mpsk_snr_c
;
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typedef
boost::shared_ptr<gr_probe_mpsk_snr_c>
gr_probe_mpsk_snr_c_sptr
;
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GR_CORE_API
gr_probe_mpsk_snr_c_sptr
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gr_make_probe_mpsk_snr_c
(
double
alpha = 0.0001);
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/*!
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* Compute the estimate SNR of an MPSK signal using the Squared Signal
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* to Noise Variance (SNV) technique.
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*
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* This technique assumes an AWGN channel.
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*
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* \param alpha Mean and variance smoothing filter constant
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* \ingroup sink_blk
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*
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* Compute the running average of the signal mean and noise variance.
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* The estimated signal mean, noise variance, and SNR are available
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* via accessors.
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*
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* This SNR estimator is inaccurate below about 7dB SNR.
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*
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*/
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class
GR_CORE_API
gr_probe_mpsk_snr_c
:
public
gr_sync_block
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{
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double
d_alpha;
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double
d_beta;
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double
d_signal_mean;
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double
d_noise_variance;
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// Factory function returning shared pointer of this class
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friend
GR_CORE_API
gr_probe_mpsk_snr_c_sptr
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gr_make_probe_mpsk_snr_c
(
double
alpha);
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// Private constructor
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gr_probe_mpsk_snr_c
(
double
alpha);
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public
:
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~
gr_probe_mpsk_snr_c
();
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int
work
(
int
noutput_items,
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gr_vector_const_void_star
&input_items,
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gr_vector_void_star
&output_items);
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// Return the estimated signal mean
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double
signal_mean
()
const
{
return
d_signal_mean; }
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// Return the estimated noise variance
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double
noise_variance
()
const
{
return
d_noise_variance; }
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// Return the estimated signal-to-noise ratio in decibels
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double
snr()
const
;
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void
set_alpha(
double
alpha);
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};
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#endif
/* INCLUDED_GR_PROBE_MPSK_SNR_C_H */
gnuradio-core
src
lib
general
gr_probe_mpsk_snr_c.h
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