MMDVM/FMCTCSSRX.cpp

141 lines
3.2 KiB
C++

/*
* Copyright (C) 2020 by Jonathan Naylor G4KLX
*
* 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 of the License, 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; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include "Config.h"
#include "Globals.h"
#include "FMCTCSSRX.h"
const struct CTCSS_TABLE {
uint8_t frequency;
float32_t coeff;
} CTCSS_TABLE_DATA[] = {
{ 67U, 1.999692F},
{ 69U, 1.999671F},
{ 71U, 1.999646F},
{ 74U, 1.999621F},
{ 77U, 1.999594F},
{ 79U, 1.999565F},
{ 82U, 1.999534F},
{ 85U, 1.999500F},
{ 88U, 1.999463F},
{ 91U, 1.999426F},
{ 94U, 1.999384F},
{ 97U, 1.999350F},
{100U, 1.999315F},
{103U, 1.999266F},
{107U, 1.999212F},
{110U, 1.999157F},
{114U, 1.999097F},
{118U, 1.999033F},
{123U, 1.998963F},
{127U, 1.998889F},
{131U, 1.998810F},
{136U, 1.998723F},
{141U, 1.998632F},
{146U, 1.998535F},
{151U, 1.998429F},
{156U, 1.998317F},
{159U, 1.998250F},
{162U, 1.998197F},
{165U, 1.998123F},
{167U, 1.998068F},
{171U, 1.997989F},
{173U, 1.997930F},
{177U, 1.997846F},
{179U, 1.997782F},
{183U, 1.997693F},
{186U, 1.997624F},
{189U, 1.997529F},
{192U, 1.997453F},
{196U, 1.997351F},
{199U, 1.997273F},
{203U, 1.997162F},
{206U, 1.997078F},
{210U, 1.996958F},
{218U, 1.996741F},
{225U, 1.996510F},
{229U, 1.996404F},
{233U, 1.996261F},
{241U, 1.995994F},
{250U, 1.995708F},
{254U, 1.995576F}};
const uint8_t CTCSS_TABLE_DATA_LEN = 50U;
// 4Hz bandwidth
const uint16_t N = 24000U / 4U;
CFMCTCSSRX::CFMCTCSSRX() :
m_coeff(0.0F),
m_threshold(0.0F),
m_count(0U),
m_q0(0.0F),
m_q1(0.0F),
m_result(false)
{
}
uint8_t CFMCTCSSRX::setParams(uint8_t frequency, uint8_t threshold)
{
for (uint8_t i = 0U; i < CTCSS_TABLE_DATA_LEN; i++) {
if (CTCSS_TABLE_DATA[i].frequency == frequency) {
m_coeff = CTCSS_TABLE_DATA[i].coeff;
break;
}
}
if (m_coeff == 0.0F)
return 4U;
m_threshold = float32_t(threshold);
return 0U;
}
bool CFMCTCSSRX::process(q15_t* samples, uint8_t length)
{
//float32_t data[RX_BLOCK_SIZE];
//::arm_q15_to_float(samples, data, length);
for (unsigned int i = 0U; i < length; i++) {
float32_t q2 = m_q1;
m_q1 = m_q0;
m_q0 = m_coeff * m_q1 - q2 + float32_t(samples[i]) / 32768.0F;
m_count++;
if (m_count == N) {
float32_t value = m_q0 * m_q0 + m_q1 * m_q1 - m_q0 * m_q1 * m_coeff;
m_result = value >= m_threshold;
DEBUG4("CTCSS value / threshold / result", value, m_threshold, m_result);
m_count = 0U;
m_q0 = 0.0F;
m_q1 = 0.0F;
}
}
return m_result;
}
void CFMCTCSSRX::reset()
{
m_q0 = 0.0F;
m_q1 = 0.0F;
m_result = false;
m_count = 0U;
}