3 * Copyright 2008 Free Software Foundation, Inc.
5 * This file is part of GNU Radio
7 * GNU Radio is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 3, or (at your option)
12 * GNU Radio is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with GNU Radio; see the file COPYING. If not, write to
19 * the Free Software Foundation, Inc., 51 Franklin Street,
20 * Boston, MA 02110-1301, USA.
27 #include <gr_probe_mpsk_snr_c.h>
28 #include <gr_io_signature.h>
30 gr_probe_mpsk_snr_c_sptr
31 gr_make_probe_mpsk_snr_c(double alpha)
33 return gr_probe_mpsk_snr_c_sptr(new gr_probe_mpsk_snr_c(alpha));
36 gr_probe_mpsk_snr_c::gr_probe_mpsk_snr_c(double alpha)
37 : gr_sync_block ("probe_mpsk_snr_c",
38 gr_make_io_signature(1, 1, sizeof(gr_complex)),
39 gr_make_io_signature(0, 0, 0)),
46 gr_probe_mpsk_snr_c::~gr_probe_mpsk_snr_c()
51 gr_probe_mpsk_snr_c::work(int noutput_items,
52 gr_vector_const_void_star &input_items,
53 gr_vector_void_star &output_items)
55 const gr_complex *in = (const gr_complex *) input_items[0];
57 for (int i = 0; i < noutput_items; i++){
58 // Update of signal mean estimate
59 double mag = abs(in[i]);
60 d_signal_mean = d_alpha*abs(in[i]) + d_beta*d_signal_mean;
62 // Update noise variance estimate
63 double noise = mag-d_signal_mean;
64 double var = noise*noise;
65 d_noise_variance = d_alpha*var + d_beta*d_noise_variance;
72 gr_probe_mpsk_snr_c::snr() const
74 if (d_noise_variance == 0.0)
77 return 10*log10(d_signal_mean*d_signal_mean/d_noise_variance);
81 gr_probe_mpsk_snr_c::set_alpha(double alpha)