3 * Copyright 2005 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 2, 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.
26 #include <gr_probe_avg_mag_sqrd_f.h>
27 #include <gr_io_signature.h>
30 gr_probe_avg_mag_sqrd_f_sptr
31 gr_make_probe_avg_mag_sqrd_f(double threshold_db, double alpha)
33 return gr_probe_avg_mag_sqrd_f_sptr(new gr_probe_avg_mag_sqrd_f(threshold_db, alpha));
36 gr_probe_avg_mag_sqrd_f::gr_probe_avg_mag_sqrd_f (double threshold_db, double alpha)
37 : gr_sync_block ("probe_avg_mag_sqrd_f",
38 gr_make_io_signature(1, 1, sizeof(float)),
39 gr_make_io_signature(0, 0, 0)),
40 d_iir(alpha), d_unmuted(false), d_level(0)
42 set_threshold (threshold_db);
45 gr_probe_avg_mag_sqrd_f::~gr_probe_avg_mag_sqrd_f()
51 gr_probe_avg_mag_sqrd_f::work(int noutput_items,
52 gr_vector_const_void_star &input_items,
53 gr_vector_void_star &output_items)
55 const float *in = (const float *) input_items[0];
57 for (int i = 0; i < noutput_items; i++){
58 double mag_sqrd = in[i]*in[i];
59 d_iir.filter(mag_sqrd); // computed for side effect: prev_output()
62 d_unmuted = d_iir.prev_output() >= d_threshold;
63 d_level = d_iir.prev_output();
68 gr_probe_avg_mag_sqrd_f::threshold() const
70 return 10 * std::log10(d_threshold);
74 gr_probe_avg_mag_sqrd_f::set_threshold(double decibels)
76 // convert to absolute threshold (mag sqrd)
77 d_threshold = std::pow(10.0, decibels/10);
81 gr_probe_avg_mag_sqrd_f::set_alpha(double alpha)
83 d_iir.set_taps(alpha);