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Adding DC estimator filter for all modes

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This commit is contained in:
Andy CA6JAU 2017-07-06 00:51:46 -04:00
parent 6c4496e034
commit f8d767913e
11 changed files with 42 additions and 34 deletions
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30
DStarRX.cpp
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@ -34,10 +34,6 @@ const unsigned int SYNC_POS = 21U * DSTAR_DATA_LENGTH_BITS;
const unsigned int SYNC_SCAN_START = SYNC_POS - 3U;
const unsigned int SYNC_SCAN_END = SYNC_POS + 3U;
// 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
// D-Star bit order version of 0x55 0x55 0x6E 0x0A
const uint32_t FRAME_SYNC_DATA = 0x00557650U;
const uint32_t FRAME_SYNC_MASK = 0x00FFFFFFU;
@ -261,16 +257,8 @@ m_pathMemory2(),
m_pathMemory3(),
m_fecOutput(),
m_rssiAccum(0U),
m_rssiCount(0U),
m_dcFilter(),
m_dcState()
m_rssiCount(0U)
{
::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;
}
void CDStarRX::reset()
@ -286,24 +274,12 @@ void CDStarRX::reset()
}
void CDStarRX::samples(const q15_t* samples, const uint16_t* rssi, uint8_t length)
{
q31_t dc_level = 0;
q31_t dcVals[20];
q31_t intSamp[20];
::arm_q15_to_q31((q15_t*)samples, intSamp, length);
::arm_biquad_cascade_df1_q31(&m_dcFilter, intSamp, dcVals, length);
for (uint8_t i = 0U; i < length; i++)
dc_level += dcVals[i];
dc_level /= length;
{
for (uint16_t i = 0U; i < length; i++) {
m_rssiAccum += rssi[i];
m_rssiCount++;
bool bit = samples[i] < (q15_t) (dc_level >> 16);
bool bit = samples[i] < m_dc_level;
if (bit != m_prev) {
if (m_pll < (PLLMAX / 2U))