/* * Copyright (C) 2014 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_DEMODULATE_H__ #define __DSP_DEMODULATE_H__ #include "dsp_types.hpp" namespace dsp { namespace demodulate { class AM { public: buffer_s16_t execute( buffer_c16_t src, buffer_s16_t dst ); }; class FM { public: /* * angle: -pi to pi. output range: -32768 to 32767. * Maximum delta-theta (output of atan2) at maximum deviation frequency: * delta_theta_max = 2 * pi * deviation / sampling_rate */ constexpr FM( const float sampling_rate, const float deviation_hz ) : z_ { 0 }, k { static_cast<float>(32767.0f / (2.0 * pi * deviation_hz / sampling_rate)) } { } buffer_s16_t execute( buffer_c16_t src, buffer_s16_t dst ); void configure(const float sampling_rate, const float deviation_hz) { k = static_cast<float>(32767.0f / (2.0 * pi * deviation_hz / sampling_rate)); } private: complex16_t::rep_type z_; float k; }; } /* namespace demodulate */ } /* namespace dsp */ #endif/*__DSP_DEMODULATE_H__*/