mirror of https://github.com/g4klx/MMDVM.git
147 lines
4.4 KiB
C++
147 lines
4.4 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.
|
|
*
|
|
* 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;
|
|
|
|
q15_t FILTER_COEFFS[] = {
|
|
0, 5, 12, 18, 21, 19, 11, -2, -15,
|
|
-25, -27, -21, -11, -3, -5, -19, -43, -69,
|
|
-83, -73, -35, 27, 98, 155, 180, 163, 109,
|
|
39, -20, -45, -26, 23, 74, 89, 39, -81,
|
|
-247, -407, -501, -480, -334, -92, 175, 388, 479,
|
|
429, 275, 99, 5, 68, 298, 626, 913, 994,
|
|
740, 115, -791, -1770, -2544, -2847, -2509, -1527, -76,
|
|
1518, 2875, 3653, 3653, 2875, 1518, -76, -1527, -2509,
|
|
-2847, -2544, -1770, -791, 115, 740, 994, 913, 626,
|
|
298, 68, 5, 99, 275, 429, 479, 388, 175,
|
|
-92, -334, -480, -501, -407, -247, -81, 39, 89,
|
|
74, 23, -26, -45, -20, 39, 109, 163, 180,
|
|
155, 98, 27, -35, -73, -83, -69, -43, -19,
|
|
-5, -3, -11, -21, -27, -25, -15, -2, 11,
|
|
19, 21, 18, 12, 5, 0};
|
|
|
|
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 && frame.m_length > 10U) {
|
|
if (m_lastFCS != frame.m_fcs) {
|
|
DEBUG1("Decoder 1 reported");
|
|
m_lastFCS = frame.m_fcs;
|
|
serial.writeAX25Data(frame.m_data, frame.m_length - 2U);
|
|
}
|
|
}
|
|
|
|
ret = m_demod2.process(output, length, frame);
|
|
if (ret && frame.m_length > 10U) {
|
|
if (m_lastFCS != frame.m_fcs) {
|
|
DEBUG1("Decoder 2 reported");
|
|
m_lastFCS = frame.m_fcs;
|
|
serial.writeAX25Data(frame.m_data, frame.m_length - 2U);
|
|
}
|
|
}
|
|
|
|
ret = m_demod3.process(output, length, frame);
|
|
if (ret && frame.m_length > 10U) {
|
|
if (m_lastFCS != frame.m_fcs) {
|
|
DEBUG1("Decoder 3 reported");
|
|
m_lastFCS = frame.m_fcs;
|
|
serial.writeAX25Data(frame.m_data, frame.m_length - 2U);
|
|
}
|
|
}
|
|
}
|
|
|