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Optimised the DC offset processing.

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This commit is contained in:
Jonathan Naylor 2017-08-18 10:48:23 +01:00
parent 064de9fef7
commit 9398d03e0b
8 changed files with 44 additions and 93 deletions
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41
IO.cpp
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@ -22,6 +22,10 @@
#include "Globals.h"
#include "IO.h"
// Generated using [b, a] = butter(1, 0.001) in MATLAB
static q31_t DC_FILTER[] = {3367972, 0, 3367972, 0, 2140747704, 0}; // {b0, 0, b1, b2, -a1, -a2}
const uint32_t DC_FILTER_STAGES = 1U; // One Biquad stage
// One symbol boxcar filter
static q15_t BOXCAR_FILTER[] = {12000, 12000, 12000, 12000, 12000, 0};
const uint16_t BOXCAR_FILTER_LEN = 6U;
@ -33,6 +37,8 @@ m_started(false),
m_rxBuffer(RX_RINGBUFFER_SIZE),
m_txBuffer(TX_RINGBUFFER_SIZE),
m_rssiBuffer(RX_RINGBUFFER_SIZE),
m_dcFilter(),
m_dcState(),
m_boxcarFilter(),
m_boxcarState(),
m_pttInvert(false),
@ -51,6 +57,12 @@ m_watchdog(0U),
m_lockout(false)
{
::memset(m_boxcarState, 0x00U, 30U * sizeof(q15_t));
::memset(m_dcState, 0x00U, 4U * sizeof(q31_t));
m_dcFilter.numStages = DC_FILTER_STAGES;
m_dcFilter.pState = m_dcState;
m_dcFilter.pCoeffs = DC_FILTER;
m_dcFilter.postShift = 0;
m_boxcarFilter.numTaps = BOXCAR_FILTER_LEN;
m_boxcarFilter.pState = m_boxcarState;
@ -136,12 +148,29 @@ void CIO::process()
q15_t vals[RX_BLOCK_SIZE];
::arm_fir_fast_q15(&m_boxcarFilter, samples, vals, RX_BLOCK_SIZE);
q31_t dcLevel = 0;
q31_t dcValues[RX_BLOCK_SIZE];
q31_t q31Vals[RX_BLOCK_SIZE];
::arm_q15_to_q31(vals, q31Vals, RX_BLOCK_SIZE);
::arm_biquad_cascade_df1_q31(&m_dcFilter, q31Vals, dcValues, RX_BLOCK_SIZE);
for (uint8_t i = 0U; i < RX_BLOCK_SIZE; i++)
dcLevel += dcValues[i];
dcLevel /= RX_BLOCK_SIZE;
q15_t offset = q15_t(__SSAT((dcLevel >> 16), 16));;
q15_t dcVals[RX_BLOCK_SIZE];
for (uint8_t i = 0U; i < RX_BLOCK_SIZE; i++)
dcVals[i] = vals[i] - offset;
if (m_modemState == STATE_IDLE) {
if (m_dstarEnable)
dstarRX.samples(vals, rssi, RX_BLOCK_SIZE);
dstarRX.samples(dcVals, rssi, RX_BLOCK_SIZE);
if (m_p25Enable)
p25RX.samples(vals, rssi, RX_BLOCK_SIZE);
p25RX.samples(dcVals, rssi, RX_BLOCK_SIZE);
if (m_dmrEnable) {
if (m_duplex)
@ -151,10 +180,10 @@ void CIO::process()
}
if (m_ysfEnable)
ysfRX.samples(vals, rssi, RX_BLOCK_SIZE);
ysfRX.samples(dcVals, rssi, RX_BLOCK_SIZE);
} else if (m_modemState == STATE_DSTAR) {
if (m_dstarEnable)
dstarRX.samples(vals, rssi, RX_BLOCK_SIZE);
dstarRX.samples(dcVals, rssi, RX_BLOCK_SIZE);
} else if (m_modemState == STATE_DMR) {
if (m_dmrEnable) {
if (m_duplex) {
@ -169,10 +198,10 @@ void CIO::process()
}
} else if (m_modemState == STATE_YSF) {
if (m_ysfEnable)
ysfRX.samples(vals, rssi, RX_BLOCK_SIZE);
ysfRX.samples(dcVals, rssi, RX_BLOCK_SIZE);
} else if (m_modemState == STATE_P25) {
if (m_p25Enable)
p25RX.samples(vals, rssi, RX_BLOCK_SIZE);
p25RX.samples(dcVals, rssi, RX_BLOCK_SIZE);
} else if (m_modemState == STATE_DSTARCAL) {
calDStarRX.samples(vals, RX_BLOCK_SIZE);
} else if (m_modemState == STATE_RSSICAL) {