mirror of https://github.com/g4klx/MMDVM.git
144 lines
4.3 KiB
C++
144 lines
4.3 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 "AX25RX.h"
|
|
|
|
// XXX There are for the wrong sample rate
|
|
|
|
// 1200Hz = -9dB, 2200Hz = 0dB; 3252Hz cutoff, 3.7 gain; cosine.
|
|
float32_t dB9[] = {
|
|
-0.00232554104135,
|
|
-0.142858725752,
|
|
-0.449053780255,
|
|
-0.770264863826,
|
|
2.77651146344,
|
|
-0.770264863826,
|
|
-0.449053780255,
|
|
-0.142858725752,
|
|
-0.00232554104135};
|
|
|
|
// 1200Hz = -6dB, 2200Hz = 0dB; 2640Hz cutoff, 2.59 gain; cosine.
|
|
float32_t dB6[] = {
|
|
-0.0209448226653,
|
|
-0.130107651829,
|
|
-0.299004731072,
|
|
-0.45336946386,
|
|
2.0629448761,
|
|
-0.45336946386,
|
|
-0.299004731072,
|
|
-0.130107651829,
|
|
-0.0209448226653};
|
|
|
|
// 1200Hz = -3dB, 2200Hz = 0dB; 1700Hz cutoff, 1.68 gain; cosine.
|
|
float32_t dB3[] = {
|
|
-0.0231416146776,
|
|
-0.0833375337803,
|
|
-0.147937602401,
|
|
-0.197411259519,
|
|
1.46066084756,
|
|
-0.197411259519,
|
|
-0.147937602401,
|
|
-0.0833375337803,
|
|
-0.0231416146776};
|
|
|
|
/*
|
|
* Generated with Scipy Filter, 152 coefficients, 1100-2300Hz bandpass,
|
|
* Hann window, starting and ending 0 value coefficients removed.
|
|
*
|
|
* np.array(
|
|
* firwin2(152,
|
|
* [
|
|
* 0.0,
|
|
* 1000.0/(sample_rate/2),
|
|
* 1100.0/(sample_rate/2),
|
|
* 2350.0/(sample_rate/2),
|
|
* 2500.0/(sample_rate/2),
|
|
* 1.0
|
|
* ],
|
|
* [0,0,1,1,0,0],
|
|
* antisymmetric = False,
|
|
* window='hann') * 32768,
|
|
* dtype=int)[10:-10]
|
|
*/
|
|
const uint32_t FILTER_LEN = 132U;
|
|
|
|
// XXX This is for the wrong sample rate
|
|
q15_t FILTER_COEFFS[] = {
|
|
4, 0, -5, -10, -13, -12, -9, -4, -2, -4, -12, -26,
|
|
-41, -52, -51, -35, -3, 39, 83, 117, 131, 118, 83, 36,
|
|
-6, -32, -30, -3, 36, 67, 66, 19, -74, -199, -323, -408,
|
|
-421, -344, -187, 17, 218, 364, 417, 369, 247, 106, 14, 26,
|
|
166, 407, 676, 865, 866, 605, 68, -675, -1484, -2171, -2547, -2471,
|
|
-1895, -882, 394, 1692, 2747, 3337, 3337, 2747, 1692, 394, -882, -1895,
|
|
-2471, -2547, -2171, -1484, -675, 68, 605, 866, 865, 676, 407, 166,
|
|
26, 14, 106, 247, 369, 417, 364, 218, 17, -187, -344, -421,
|
|
-408, -323, -199, -74, 19, 66, 67, 36, -3, -30, -32, -6,
|
|
36, 83, 118, 131, 117, 83, 39, -3, -35, -51, -52, -41,
|
|
-26, -12, -4, -2, -4, -9, -12, -13, -10, -5, 0, 4};
|
|
|
|
CAX25RX::CAX25RX() :
|
|
m_filter(),
|
|
m_state(),
|
|
m_demod1(dB3, 9U),
|
|
m_demod2(dB6, 9U),
|
|
m_demod3(dB9, 9U),
|
|
m_lastFCS(0U)
|
|
{
|
|
m_filter.numTaps = FILTER_LEN;
|
|
m_filter.pState = m_state;
|
|
m_filter.pCoeffs = FILTER_COEFFS;
|
|
}
|
|
|
|
void CAX25RX::samples(q15_t* samples, uint8_t length)
|
|
{
|
|
q15_t output[RX_BLOCK_SIZE];
|
|
::arm_fir_fast_q15(&m_filter, samples, output, RX_BLOCK_SIZE);
|
|
|
|
CAX25Frame frame;
|
|
|
|
bool ret = m_demod1.process(output, length, frame);
|
|
if (ret) {
|
|
if (m_lastFCS != frame.m_fcs) {
|
|
DEBUG1("Decoder 1 reported");
|
|
m_lastFCS = frame.m_fcs;
|
|
serial.writeAX25Data(frame.m_data, frame.m_length);
|
|
}
|
|
}
|
|
|
|
ret = m_demod2.process(output, length, frame);
|
|
if (ret) {
|
|
if (m_lastFCS != frame.m_fcs) {
|
|
DEBUG1("Decoder 2 reported");
|
|
m_lastFCS = frame.m_fcs;
|
|
serial.writeAX25Data(frame.m_data, frame.m_length);
|
|
}
|
|
}
|
|
|
|
ret = m_demod3.process(output, length, frame);
|
|
if (ret) {
|
|
if (m_lastFCS != frame.m_fcs) {
|
|
DEBUG1("Decoder 3 reported");
|
|
m_lastFCS = frame.m_fcs;
|
|
serial.writeAX25Data(frame.m_data, frame.m_length);
|
|
}
|
|
}
|
|
}
|
|
|