57 lines
1.5 KiB
C++
57 lines
1.5 KiB
C++
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/*
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* Copyright (C) 2014 Jared Boone, ShareBrained Technology, Inc.
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* Copyright (C) 2018 Furrtek
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*
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* This file is part of PortaPack.
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*
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* This program 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 2, or (at your option)
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* any later version.
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*
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* This program 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 this program; 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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#include "dsp_goertzel.hpp"
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#include "complex.hpp"
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#include "sine_table.hpp"
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namespace dsp {
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GoertzelDetector::GoertzelDetector(
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const float frequency,
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const uint32_t sample_rate
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) {
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coefficient = 2.0 * sin_f32((2.0 * pi * frequency / sample_rate) - pi / 2.0);
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}
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float GoertzelDetector::execute(
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const buffer_s16_t& src
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) {
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const size_t count = src.count;
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for (size_t i = 0; i < count; i++) {
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s[2] = s[1];
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s[1] = s[0];
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s[0] = src.p[i] + coefficient * s[1] - s[2];
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}
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const uint32_t sq0 = s[0] * s[0];
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const uint32_t sq1 = s[1] * s[1];
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float magnitude = __builtin_sqrtf(sq0 + sq1 - s[0] * s[1] * coefficient);
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return magnitude;
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}
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} /* namespace dsp */
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