/* * Copyright (C) 2015 Jared Boone, ShareBrained Technology, Inc. * * This file is part of PortaPack. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2, or (at your option) * any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; see the file COPYING. If not, write to * the Free Software Foundation, Inc., 51 Franklin Street, * Boston, MA 02110-1301, USA. */ #ifndef __DSP_SQUELCH_H__ #define __DSP_SQUELCH_H__ #include "buffer.hpp" #include "dsp_iir.hpp" #include "dsp_iir_config.hpp" #include #include class FMSquelch { public: /* Check if noise level is lower than threshold. * Returns true if noise is below threshold. */ bool execute(const buffer_f32_t& audio); void set_threshold(const float new_value); bool enabled() const; private: static constexpr size_t N = 32; float threshold_squared{0.0f}; IIRBiquadFilter non_audio_hpf{non_audio_hpf_config}; }; #endif /*__DSP_SQUELCH_H__*/