mirror of https://github.com/g4klx/MMDVM.git
150 lines
2.9 KiB
C++
150 lines
2.9 KiB
C++
/*
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* Copyright (C) 2020 by Jonathan Naylor G4KLX
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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 of the License, or
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* (at your option) 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; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include "Config.h"
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#include "Globals.h"
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#include "FMCTCSSRX.h"
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const struct CTCSS_TABLE {
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uint8_t frequency;
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long coeff;
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} CTCSS_TABLE_DATA[] = {
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{67, 65527},
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{69, 65526},
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{71, 65525},
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{74, 65524},
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{77, 65523},
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{79, 65522},
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{82, 65521},
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{85, 65520},
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{88, 65519},
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{91, 65518},
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{94, 65517},
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{97, 65516},
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{100, 65514},
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{103, 65513},
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{107, 65511},
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{110, 65509},
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{114, 65507},
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{123, 65503},
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{127, 65501},
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{131, 65498},
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{136, 65495},
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{141, 65492},
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{146, 65489},
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{150, 65487},
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{151, 65486},
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{156, 65482},
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{159, 65480},
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{162, 65478},
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{165, 65476},
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{167, 65474},
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{171, 65472},
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{173, 65470},
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{177, 65467},
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{179, 65465},
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{183, 65462},
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{186, 65460},
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{188, 65458},
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{189, 65457},
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{192, 65454},
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{196, 65451},
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{199, 65448},
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{203, 65445},
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{206, 65442},
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{210, 65438},
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{213, 65435},
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{218, 65431},
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{221, 65428},
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{225, 65424},
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{229, 65420},
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{233, 65416},
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{237, 65412},
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{241, 65407},
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{245, 65403},
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{250, 65398},
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{254, 65393}
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};
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const uint8_t CTCSS_TABLE_DATA_LEN = 55U;
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// 4Hz bandwidth
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const uint16_t N = 24000U / 4U;
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CFMCTCSSRX::CFMCTCSSRX() :
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m_coeff(0),
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m_thresholdSquared(0U),
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m_count(0U),
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m_q0(0),
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m_q1(0),
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m_result(false)
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{
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}
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uint8_t CFMCTCSSRX::setParams(uint8_t frequency, uint8_t threshold)
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{
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for (uint8_t i = 0U; i < CTCSS_TABLE_DATA_LEN; i++) {
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if (CTCSS_TABLE_DATA[i].frequency == frequency) {
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m_coeff = CTCSS_TABLE_DATA[i].coeff;
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break;
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}
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}
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if (m_coeff == 0)
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return 4U;
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m_thresholdSquared = (long)(threshold * threshold);
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return 0U;
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}
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bool CFMCTCSSRX::process(const q15_t* samples, uint8_t length)
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{
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for (unsigned int i = 0U; i < length; i++) {
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long sampleLong = (long)samples[i];
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long q2 = m_q1;
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m_q1 = m_q0;
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m_q0 = m_coeff * m_q1 - q2 + sampleLong;
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m_count++;
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if(m_count == N) {
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m_count = 0;
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if(!m_result) {
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long magnitudeSquared = m_q0 * m_q0 + m_q1 * m_q1 - m_q0 * m_q1 * m_coeff;
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if(magnitudeSquared >= m_thresholdSquared) {
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m_result = magnitudeSquared >= m_thresholdSquared;
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m_q0 = 0;
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m_q1 = 0;
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}
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}
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}
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}
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return m_result;
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}
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void CFMCTCSSRX::reset()
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{
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m_q0 = 0;
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m_q1 = 0;
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m_result = false;
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m_count = 0U;
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}
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