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Merge NXDN RRC filter + SINC filter (TX)

This commit is contained in:
Andy CA6JAU 2018-06-04 00:36:44 -04:00
parent e1e9b2682f
commit 9f9abe496d
2 changed files with 14 additions and 26 deletions
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38
NXDNTX.cpp
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@ -23,21 +23,21 @@
#include "NXDNDefines.h"
// Generated using rcosdesign(0.2, 8, 20, 'sqrt') in MATLAB
static q15_t RRC_0_2_FILTER[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 201, 174, 140, 99, 52, 0, -55, -112, -170, -226, -278, -325, -365, -397, -417, -427, -424, -407, -377, -333, -277, -208,
-128, -40, 56, 156, 258, 358, 455, 544, 622, 687, 736, 766, 775, 762, 725, 664, 579, 471, 342, 193, 27, -151, -338, -528,
-718, -901, -1072, -1225, -1354, -1454, -1520, -1547, -1530, -1466, -1353, -1189, -972, -704, -385, -18, 394, 846, 1333,
1850, 2388, 2940, 3498, 4053, 4598, 5122, 5619, 6079, 6494, 6859, 7166, 7410, 7588, 7696, 7732, 7696, 7588, 7410, 7166,
6859, 6494, 6079, 5619, 5122, 4598, 4053, 3498, 2940, 2388, 1850, 1333, 846, 394, -18, -385, -704, -972, -1189, -1353,
-1466, -1530, -1547, -1520, -1454, -1354, -1225, -1072, -901, -718, -528, -338, -151, 27, 193, 342, 471, 579, 664, 725,
762, 775, 766, 736, 687, 622, 544, 455, 358, 258, 156, 56, -40, -128, -208, -277, -333, -377, -407, -424, -427, -417, -397,
-365, -325, -278, -226, -170, -112, -55, 0, 52, 99, 140, 174, 201}; // numTaps = 180, L = 20
// NXDN RRC filter + SINC filter
static q15_t RRC_0_2_FILTER[] = {51, 71, 92, 112, 129, 141, 144, 138, 120, 87, 39, -26, -107, -204, -314, -437, -567, -702, -835,
-932,-1066, -1176, -1257, -1304, -1314, -1284, -1213, -1099, -944, -749, -519, -257, 30, 335, 651,
968, 1277, 1569, 1832, 2058, 2237, 2360, 2420, 2412, 2329, 2170, 1935, 1623, 1239, 790, 283, -271,
-858, -1466, -2076, -2671, -3233, -3742, -4178, -4521, -4754, -4857, -4815, -4614, -4242, -3690,
-2952, -2025, -912, 385, 1855, 3488, 5266, 7172, 9183, 11274, 13418, 15585, 17746, 19869, 21923,
23876, 25700, 27364, 28844, 30116, 31159, 31956, 32495, 32767, 32767, 32495, 31956, 31159, 30116,
28844, 27364, 25700, 23876, 21923, 19869, 17746, 15585, 13418, 11274, 9183, 7172, 5266, 3488, 1855,
385, -912, -2025, -2952, -3690, -4242, -4614, -4815, -4857, -4754, -4521, -4178, -3742, -3233, -2671,
-2076, -1466, -858, -271, 283, 790, 1239, 1623, 1935, 2170, 2329, 2412, 2420, 2360, 2237, 2058, 1832,
1569, 1277, 968, 651, 335, 30, -257, -519, -749, -944, -1099, -1213, -1284, -1314, -1304, -1257,
-1176, -1066, -932, -835, -702, -567, -437, -314, -204, -107, -26, 39, 87, 120, 138, 144, 141, 129,
112, 92, 71, 51}; // numTaps = 180, L = 20
const uint16_t RRC_0_2_FILTER_PHASE_LEN = 9U; // phaseLength = numTaps/L
static q15_t NXDN_SINC_FILTER[] = {572, -1003, -253, 254, 740, 1290, 1902, 2527, 3090, 3517, 3747, 3747, 3517, 3090, 2527, 1902,
1290, 740, 254, -253, -1003, 572};
const uint16_t NXDN_SINC_FILTER_LEN = 22U;
const q15_t NXDN_LEVELA = 735;
const q15_t NXDN_LEVELB = 245;
const q15_t NXDN_LEVELC = -245;
@ -49,25 +49,18 @@ const uint8_t NXDN_SYNC = 0x5FU;
CNXDNTX::CNXDNTX() :
m_buffer(4000U),
m_modFilter(),
m_sincFilter(),
m_modState(),
m_sincState(),
m_poBuffer(),
m_poLen(0U),
m_poPtr(0U),
m_txDelay(240U) // 200ms
{
::memset(m_modState, 0x00U, 16U * sizeof(q15_t));
::memset(m_sincState, 0x00U, 70U * sizeof(q15_t));
m_modFilter.L = NXDN_RADIO_SYMBOL_LENGTH;
m_modFilter.phaseLength = RRC_0_2_FILTER_PHASE_LEN;
m_modFilter.pCoeffs = RRC_0_2_FILTER;
m_modFilter.pState = m_modState;
m_sincFilter.numTaps = NXDN_SINC_FILTER_LEN;
m_sincFilter.pState = m_sincState;
m_sincFilter.pCoeffs = NXDN_SINC_FILTER;
}
void CNXDNTX::process()
@ -128,7 +121,6 @@ uint8_t CNXDNTX::writeData(const uint8_t* data, uint8_t length)
void CNXDNTX::writeByte(uint8_t c)
{
q15_t inBuffer[4U];
q15_t intBuffer[NXDN_RADIO_SYMBOL_LENGTH * 4U];
q15_t outBuffer[NXDN_RADIO_SYMBOL_LENGTH * 4U];
const uint8_t MASK = 0xC0U;
@ -150,9 +142,7 @@ void CNXDNTX::writeByte(uint8_t c)
}
}
::arm_fir_interpolate_q15(&m_modFilter, inBuffer, intBuffer, 4U);
::arm_fir_fast_q15(&m_sincFilter, intBuffer, outBuffer, NXDN_RADIO_SYMBOL_LENGTH * 4U);
::arm_fir_interpolate_q15(&m_modFilter, inBuffer, outBuffer, 4U);
io.write(STATE_NXDN, outBuffer, NXDN_RADIO_SYMBOL_LENGTH * 4U);
}

2
NXDNTX.h
View File

@ -38,9 +38,7 @@ public:
private:
CSerialRB m_buffer;
arm_fir_interpolate_instance_q15 m_modFilter;
arm_fir_instance_q15 m_sincFilter;
q15_t m_modState[16U]; // blockSize + phaseLength - 1, 4 + 9 - 1 plus some spare
q15_t m_sincState[70U]; // NoTaps + BlockSize - 1, 22 + 40 - 1 plus some spare
uint8_t m_poBuffer[1200U];
uint16_t m_poLen;
uint16_t m_poPtr;