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IntHalfbandFilters: Optimized versions of workInterpolateCenter and myInterpolate

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f4exb 2017-04-26 00:07:57 +02:00
parent 02981b4f08
commit 6b3bdef3a7
1 changed files with 121 additions and 14 deletions
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135
sdrbase/dsp/inthalfbandfilter.h
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@ -26,7 +26,16 @@
template<uint32_t HBFilterOrder>
class SDRANGEL_API IntHalfbandFilter {
public:
IntHalfbandFilter();
IntHalfbandFilter() :
m_ptr(0),
m_state(0)
{
for (int i = 0; i < HBFIRFilterTraits<HBFilterOrder>::hbOrder + 1; i++)
{
m_samples[i][0] = 0;
m_samples[i][1] = 0;
}
}
// downsample by 2, return center part of original spectrum
bool workDecimateCenter(Sample* sample)
@ -103,6 +112,40 @@ public:
}
}
/** Optimized upsampler by 2 not calculating FIR with inserted null samples */
bool workInterpolateCenterOptimized(Sample* sampleIn, Sample *SampleOut)
{
switch(m_state)
{
case 0:
// return the middle peak
SampleOut->setReal(m_samples[m_ptr + (HBFIRFilterTraits<HBFilterOrder>::hbOrder/4) - 1][0]);
SampleOut->setImag(m_samples[m_ptr + (HBFIRFilterTraits<HBFilterOrder>::hbOrder/4) - 1][1]);
m_state = 1; // next state
return false; // tell caller we didn't consume the sample
default:
// calculate with non null samples
doInterpolateFIR(SampleOut);
// insert sample into ring double buffer
m_samples[m_ptr][0] = sampleIn->real();
m_samples[m_ptr][1] = sampleIn->imag();
m_samples[m_ptr + HBFIRFilterTraits<HBFilterOrder>::hbOrder/2][0] = sampleIn->real();
m_samples[m_ptr + HBFIRFilterTraits<HBFilterOrder>::hbOrder/2][1] = sampleIn->imag();
// advance pointer
if (m_ptr < (HBFIRFilterTraits<HBFilterOrder>::hbOrder/2) - 1) {
m_ptr++;
} else {
m_ptr = 0;
}
m_state = 0; // next state
return true; // tell caller we consumed the sample
}
}
bool workDecimateCenter(qint32 *x, qint32 *y)
{
// insert sample into ring-buffer
@ -544,6 +587,29 @@ public:
m_ptr = HBFIRFilterTraits<HBFilterOrder>::hbMod[m_ptr + 2 - 1];
}
void myInterpolateOptimized(qint32 *x1, qint32 *y1, qint32 *x2, qint32 *y2)
{
// insert sample into ring double buffer
m_samples[m_ptr][0] = *x1;
m_samples[m_ptr][1] = *y1;
m_samples[m_ptr + HBFIRFilterTraits<HBFilterOrder>::hbOrder/2][0] = *x1;
m_samples[m_ptr + HBFIRFilterTraits<HBFilterOrder>::hbOrder/2][1] = *y1;
// advance pointer
if (m_ptr < (HBFIRFilterTraits<HBFilterOrder>::hbOrder/2) - 1) {
m_ptr++;
} else {
m_ptr = 0;
}
// first output sample calculated with the middle peak
*x1 = m_samples[m_ptr + (HBFIRFilterTraits<HBFilterOrder>::hbOrder/4) - 1][0];
*y1 = m_samples[m_ptr + (HBFIRFilterTraits<HBFilterOrder>::hbOrder/4) - 1][1];
// second sample calculated with the filter
doInterpolateFIR(x2, y2);
}
protected:
qint32 m_samples[HBFIRFilterTraits<HBFilterOrder>::hbOrder + 1][2]; // Valgrind optim (from qint16)
qint16 m_ptr;
@ -581,6 +647,48 @@ protected:
sample->setImag(qAcc >> (HBFIRFilterTraits<HBFilterOrder>::hbShift -1));
}
void doInterpolateFIR(Sample* sample)
{
qint16 a = m_ptr;
qint16 b = m_ptr + (HBFIRFilterTraits<HBFilterOrder>::hbOrder / 2) - 1;
// go through samples in buffer
qint32 iAcc = 0;
qint32 qAcc = 0;
for (int i = 0; i < HBFIRFilterTraits<HBFilterOrder>::hbOrder / 4; i++)
{
iAcc += (m_samples[a][0] + m_samples[b][0]) * HBFIRFilterTraits<HBFilterOrder>::hbCoeffs[i];
qAcc += (m_samples[a][1] + m_samples[b][1]) * HBFIRFilterTraits<HBFilterOrder>::hbCoeffs[i];
a++;
b--;
}
sample->setReal(iAcc >> (HBFIRFilterTraits<HBFilterOrder>::hbShift -1));
sample->setImag(qAcc >> (HBFIRFilterTraits<HBFilterOrder>::hbShift -1));
}
void doInterpolateFIR(qint32 *x, qint32 *y)
{
qint16 a = m_ptr;
qint16 b = m_ptr + (HBFIRFilterTraits<HBFilterOrder>::hbOrder / 2) - 1;
// go through samples in buffer
qint32 iAcc = 0;
qint32 qAcc = 0;
for (int i = 0; i < HBFIRFilterTraits<HBFilterOrder>::hbOrder / 4; i++)
{
iAcc += (m_samples[a][0] + m_samples[b][0]) * HBFIRFilterTraits<HBFilterOrder>::hbCoeffs[i];
qAcc += (m_samples[a][1] + m_samples[b][1]) * HBFIRFilterTraits<HBFilterOrder>::hbCoeffs[i];
a++;
b--;
}
*x = iAcc >> (HBFIRFilterTraits<HBFilterOrder>::hbShift -1);
*y = qAcc >> (HBFIRFilterTraits<HBFilterOrder>::hbShift -1);
}
void doFIR(qint32 *x, qint32 *y)
{
// Coefficents. This is a sinc function:
@ -621,18 +729,17 @@ protected:
};
template<uint32_t HBFilterOrder>
IntHalfbandFilter<HBFilterOrder>::IntHalfbandFilter()
{
for (int i = 0; i < HBFIRFilterTraits<HBFilterOrder>::hbOrder + 1; i++)
{
m_samples[i][0] = 0;
m_samples[i][1] = 0;
}
m_ptr = 0;
m_state = 0;
}
//template<uint32_t HBFilterOrder>
//IntHalfbandFilter<HBFilterOrder>::IntHalfbandFilter()
//{
// for (int i = 0; i < HBFIRFilterTraits<HBFilterOrder>::hbOrder + 1; i++)
// {
// m_samples[i][0] = 0;
// m_samples[i][1] = 0;
// }
//
// m_ptr = 0;
// m_state = 0;
//}
#endif // INCLUDE_INTHALFBANDFILTER_H