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sdrangel/sdrbase/dsp/inthalfbandfilterdbf.h

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23 KiB
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///////////////////////////////////////////////////////////////////////////////////
// Copyright (C) 2018 F4EXB //
// written by Edouard Griffiths //
// //
// Float half-band FIR based interpolator and decimator //
// This is the double buffer variant //
// //
// 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 as version 3 of the License, or //
// //
// 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 V3 for more details. //
// //
// You should have received a copy of the GNU General Public License //
// along with this program. If not, see <http://www.gnu.org/licenses/>. //
///////////////////////////////////////////////////////////////////////////////////
#ifndef INCLUDE_INTHALFBANDFILTER_DBF_H
#define INCLUDE_INTHALFBANDFILTER_DBF_H
#include <stdint.h>
#include "dsp/dsptypes.h"
#include "dsp/hbfiltertraits.h"
#include "export.h"
template<typename AccuType, typename SampleType, uint32_t HBFilterOrder>
class SDRBASE_API IntHalfbandFilterDBF {
public:
IntHalfbandFilterDBF();
// downsample by 2, return center part of original spectrum
bool workDecimateCenter(Sample* sample)
{
// insert sample into ring-buffer
storeSampleFixReal((FixReal) sample->real(), (FixReal) sample->imag());
switch(m_state)
{
case 0:
// advance write-pointer
advancePointer();
// next state
m_state = 1;
// tell caller we don't have a new sample
return false;
default:
// save result
doFIR(sample);
// advance write-pointer
advancePointer();
// next state
m_state = 0;
// tell caller we have a new sample
return true;
}
}
// upsample by 2, return center part of original spectrum - double buffer variant
bool workInterpolateCenterZeroStuffing(Sample* sampleIn, Sample *SampleOut)
{
switch(m_state)
{
case 0:
// insert sample into ring-buffer
storeSampleFixReal((FixReal) 0, (FixReal) 0);
// save result
doFIR(SampleOut);
// advance write-pointer
advancePointer();
// next state
m_state = 1;
// tell caller we didn't consume the sample
return false;
default:
// insert sample into ring-buffer
storeSampleFixReal((FixReal) sampleIn->real(), (FixReal) sampleIn->imag());
// save result
doFIR(SampleOut);
// advance write-pointer
advancePointer();
// next state
m_state = 0;
// tell caller we consumed the sample
return true;
}
}
/** Optimized upsampler by 2 not calculating FIR with inserted null samples */
bool workInterpolateCenter(Sample* sampleIn, Sample *SampleOut)
{
switch(m_state)
{
case 0:
// return the middle peak
SampleOut->setReal(m_samplesDB[m_ptr + (HBFIRFilterTraits<HBFilterOrder>::hbOrder/4) - 1][0]);
SampleOut->setImag(m_samplesDB[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_samplesDB[m_ptr][0] = sampleIn->real();
m_samplesDB[m_ptr][1] = sampleIn->imag();
m_samplesDB[m_ptr + HBFIRFilterTraits<HBFilterOrder>::hbOrder/2][0] = sampleIn->real();
m_samplesDB[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
}
}
// downsample by 2, return lower half of original spectrum
bool workDecimateLowerHalf(Sample* sample)
{
switch(m_state)
{
case 0:
// insert sample into ring-buffer
storeSampleFixReal((FixReal) -sample->imag(), (FixReal) sample->real());
// advance write-pointer
advancePointer();
// next state
m_state = 1;
// tell caller we don't have a new sample
return false;
case 1:
// insert sample into ring-buffer
storeSampleFixReal((FixReal) -sample->real(), (FixReal) -sample->imag());
// save result
doFIR(sample);
// advance write-pointer
advancePointer();
// next state
m_state = 2;
// tell caller we have a new sample
return true;
case 2:
// insert sample into ring-buffer
storeSampleFixReal((FixReal) sample->imag(), (FixReal) -sample->real());
// advance write-pointer
advancePointer();
// next state
m_state = 3;
// tell caller we don't have a new sample
return false;
default:
// insert sample into ring-buffer
storeSampleFixReal((FixReal) sample->real(), (FixReal) sample->imag());
// save result
doFIR(sample);
// advance write-pointer
advancePointer();
// next state
m_state = 0;
// tell caller we have a new sample
return true;
}
}
/** Optimized upsampler by 2 not calculating FIR with inserted null samples */
bool workInterpolateLowerHalf(Sample* sampleIn, Sample *sampleOut)
{
Sample s;
switch(m_state)
{
case 0:
// return the middle peak
sampleOut->setReal(m_samplesDB[m_ptr + (HBFIRFilterTraits<HBFilterOrder>::hbOrder/4) - 1][1]); // imag
sampleOut->setImag(-m_samplesDB[m_ptr + (HBFIRFilterTraits<HBFilterOrder>::hbOrder/4) - 1][0]); // - real
m_state = 1; // next state
return false; // tell caller we didn't consume the sample
case 1:
// calculate with non null samples
doInterpolateFIR(&s);
sampleOut->setReal(-s.real());
sampleOut->setImag(-s.imag());
// insert sample into ring double buffer
m_samplesDB[m_ptr][0] = sampleIn->real();
m_samplesDB[m_ptr][1] = sampleIn->imag();
m_samplesDB[m_ptr + HBFIRFilterTraits<HBFilterOrder>::hbOrder/2][0] = sampleIn->real();
m_samplesDB[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 = 2; // next state
return true; // tell caller we consumed the sample
case 2:
// return the middle peak
sampleOut->setReal(-m_samplesDB[m_ptr + (HBFIRFilterTraits<HBFilterOrder>::hbOrder/4) - 1][1]); // - imag
sampleOut->setImag(m_samplesDB[m_ptr + (HBFIRFilterTraits<HBFilterOrder>::hbOrder/4) - 1][0]); // real
m_state = 3; // next state
return false; // tell caller we didn't consume the sample
default:
// calculate with non null samples
doInterpolateFIR(&s);
sampleOut->setReal(s.real());
sampleOut->setImag(s.imag());
// insert sample into ring double buffer
m_samplesDB[m_ptr][0] = sampleIn->real();
m_samplesDB[m_ptr][1] = sampleIn->imag();
m_samplesDB[m_ptr + HBFIRFilterTraits<HBFilterOrder>::hbOrder/2][0] = sampleIn->real();
m_samplesDB[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
}
}
// upsample by 2, from lower half of original spectrum - double buffer variant
bool workInterpolateLowerHalfZeroStuffing(Sample* sampleIn, Sample *sampleOut)
{
Sample s;
switch(m_state)
{
case 0:
// insert sample into ring-buffer
storeSampleFixReal((FixReal) 0, (FixReal) 0);
// save result
doFIR(&s);
sampleOut->setReal(s.imag());
sampleOut->setImag(-s.real());
// advance write-pointer
advancePointer();
// next state
m_state = 1;
// tell caller we didn't consume the sample
return false;
case 1:
// insert sample into ring-buffer
storeSampleFixReal((FixReal) sampleIn->real(), (FixReal) sampleIn->imag());
// save result
doFIR(&s);
sampleOut->setReal(-s.real());
sampleOut->setImag(-s.imag());
// advance write-pointer
advancePointer();
// next state
m_state = 2;
// tell caller we consumed the sample
return true;
case 2:
// insert sample into ring-buffer
storeSampleFixReal((FixReal) 0, (FixReal) 0);
// save result
doFIR(&s);
sampleOut->setReal(-s.imag());
sampleOut->setImag(s.real());
// advance write-pointer
advancePointer();
// next state
m_state = 3;
// tell caller we didn't consume the sample
return false;
default:
// insert sample into ring-buffer
storeSampleFixReal((FixReal) sampleIn->real(), (FixReal) sampleIn->imag());
// save result
doFIR(&s);
sampleOut->setReal(s.real());
sampleOut->setImag(s.imag());
// advance write-pointer
advancePointer();
// next state
m_state = 0;
// tell caller we consumed the sample
return true;
}
}
// downsample by 2, return upper half of original spectrum
bool workDecimateUpperHalf(Sample* sample)
{
switch(m_state)
{
case 0:
// insert sample into ring-buffer
storeSampleFixReal((FixReal) sample->imag(), (FixReal) -sample->real());
// advance write-pointer
advancePointer();
// next state
m_state = 1;
// tell caller we don't have a new sample
return false;
case 1:
// insert sample into ring-buffer
storeSampleFixReal((FixReal) -sample->real(), (FixReal) -sample->imag());
// save result
doFIR(sample);
// advance write-pointer
advancePointer();
// next state
m_state = 2;
// tell caller we have a new sample
return true;
case 2:
// insert sample into ring-buffer
storeSampleFixReal((FixReal) -sample->imag(), (FixReal) sample->real());
// advance write-pointer
advancePointer();
// next state
m_state = 3;
// tell caller we don't have a new sample
return false;
default:
// insert sample into ring-buffer
storeSampleFixReal((FixReal) sample->real(), (FixReal) sample->imag());
// save result
doFIR(sample);
// advance write-pointer
advancePointer();
// next state
m_state = 0;
// tell caller we have a new sample
return true;
}
}
/** Optimized upsampler by 2 not calculating FIR with inserted null samples */
bool workInterpolateUpperHalf(Sample* sampleIn, Sample *sampleOut)
{
Sample s;
switch(m_state)
{
case 0:
// return the middle peak
sampleOut->setReal(-m_samplesDB[m_ptr + (HBFIRFilterTraits<HBFilterOrder>::hbOrder/4) - 1][1]); // - imag
sampleOut->setImag(m_samplesDB[m_ptr + (HBFIRFilterTraits<HBFilterOrder>::hbOrder/4) - 1][0]); // + real
m_state = 1; // next state
return false; // tell caller we didn't consume the sample
case 1:
// calculate with non null samples
doInterpolateFIR(&s);
sampleOut->setReal(-s.real());
sampleOut->setImag(-s.imag());
// insert sample into ring double buffer
m_samplesDB[m_ptr][0] = sampleIn->real();
m_samplesDB[m_ptr][1] = sampleIn->imag();
m_samplesDB[m_ptr + HBFIRFilterTraits<HBFilterOrder>::hbOrder/2][0] = sampleIn->real();
m_samplesDB[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 = 2; // next state
return true; // tell caller we consumed the sample
case 2:
// return the middle peak
sampleOut->setReal(m_samplesDB[m_ptr + (HBFIRFilterTraits<HBFilterOrder>::hbOrder/4) - 1][1]); // + imag
sampleOut->setImag(-m_samplesDB[m_ptr + (HBFIRFilterTraits<HBFilterOrder>::hbOrder/4) - 1][0]); // - real
m_state = 3; // next state
return false; // tell caller we didn't consume the sample
default:
// calculate with non null samples
doInterpolateFIR(&s);
sampleOut->setReal(s.real());
sampleOut->setImag(s.imag());
// insert sample into ring double buffer
m_samplesDB[m_ptr][0] = sampleIn->real();
m_samplesDB[m_ptr][1] = sampleIn->imag();
m_samplesDB[m_ptr + HBFIRFilterTraits<HBFilterOrder>::hbOrder/2][0] = sampleIn->real();
m_samplesDB[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
}
}
// upsample by 2, move original spectrum to upper half - double buffer variant
bool workInterpolateUpperHalfZeroStuffing(Sample* sampleIn, Sample *sampleOut)
{
Sample s;
switch(m_state)
{
case 0:
// insert sample into ring-buffer
storeSampleFixReal((FixReal) 0, (FixReal) 0);
// save result
doFIR(&s);
sampleOut->setReal(-s.imag());
sampleOut->setImag(s.real());
// advance write-pointer
advancePointer();
// next state
m_state = 1;
// tell caller we didn't consume the sample
return false;
case 1:
// insert sample into ring-buffer
storeSampleFixReal((FixReal) sampleIn->real(), (FixReal) sampleIn->imag());
// save result
doFIR(&s);
sampleOut->setReal(-s.real());
sampleOut->setImag(-s.imag());
// advance write-pointer
advancePointer();
// next state
m_state = 2;
// tell caller we consumed the sample
return true;
case 2:
// insert sample into ring-buffer
storeSampleFixReal((FixReal) 0, (FixReal) 0);
// save result
doFIR(&s);
sampleOut->setReal(s.imag());
sampleOut->setImag(-s.real());
// advance write-pointer
advancePointer();
// next state
m_state = 3;
// tell caller we didn't consume the sample
return false;
default:
// insert sample into ring-buffer
storeSampleFixReal((FixReal) sampleIn->real(), (FixReal) sampleIn->imag());
// save result
doFIR(&s);
sampleOut->setReal(s.real());
sampleOut->setImag(s.imag());
// advance write-pointer
advancePointer();
// next state
m_state = 0;
// tell caller we consumed the sample
return true;
}
}
void myDecimate(const Sample* sample1, Sample* sample2)
{
storeSampleFixReal((FixReal) sample1->real(), (FixReal) sample1->imag());
advancePointer();
storeSampleFixReal((FixReal) sample2->real(), (FixReal) sample2->imag());
doFIR(sample2);
advancePointer();
}
void myDecimate(AccuType x1, AccuType y1, AccuType *x2, AccuType *y2)
{
storeSampleAccu(x1, y1);
advancePointer();
storeSampleAccu(*x2, *y2);
doFIRAccu(x2, y2);
advancePointer();
}
/** Simple zero stuffing and filter */
void myInterpolateZeroStuffing(Sample* sample1, Sample* sample2)
{
storeSampleFixReal((FixReal) sample1->real(), (FixReal) sample1->imag());
doFIR(sample1);
advancePointer();
storeSampleFixReal((FixReal) 0, (FixReal) 0);
doFIR(sample2);
advancePointer();
}
/** Optimized upsampler by 2 not calculating FIR with inserted null samples */
void myInterpolate(qint32 *x1, qint32 *y1, qint32 *x2, qint32 *y2)
{
// insert sample into ring double buffer
m_samplesDB[m_ptr][0] = *x1;
m_samplesDB[m_ptr][1] = *y1;
m_samplesDB[m_ptr + HBFIRFilterTraits<HBFilterOrder>::hbOrder/2][0] = *x1;
m_samplesDB[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_samplesDB[m_ptr + (HBFIRFilterTraits<HBFilterOrder>::hbOrder/4) - 1][0];
*y1 = m_samplesDB[m_ptr + (HBFIRFilterTraits<HBFilterOrder>::hbOrder/4) - 1][1];
// second sample calculated with the filter
doInterpolateFIR(x2, y2);
}
protected:
SampleType m_samplesDB[2*(HBFIRFilterTraits<HBFilterOrder>::hbOrder - 1)][2]; // double buffer technique
int m_ptr;
int m_size;
int m_state;
void storeSampleFixReal(const FixReal& sampleI, const FixReal& sampleQ)
{
m_samplesDB[m_ptr][0] = sampleI / SDR_RX_SCALED;
m_samplesDB[m_ptr][1] = sampleQ / SDR_RX_SCALED;
m_samplesDB[m_ptr + m_size][0] = sampleI / SDR_RX_SCALED;
m_samplesDB[m_ptr + m_size][1] = sampleQ / SDR_RX_SCALED;
}
void storeSampleAccu(AccuType x, AccuType y)
{
m_samplesDB[m_ptr][0] = x;
m_samplesDB[m_ptr][1] = y;
m_samplesDB[m_ptr + m_size][0] = x;
m_samplesDB[m_ptr + m_size][1] = y;
}
void advancePointer()
{
m_ptr = m_ptr + 1 < m_size ? m_ptr + 1: 0;
}
void doFIR(Sample* sample)
{
int a = m_ptr + m_size; // tip pointer
int b = m_ptr + 1; // tail pointer
AccuType iAcc = 0;
AccuType qAcc = 0;
for (int i = 0; i < HBFIRFilterTraits<HBFilterOrder>::hbOrder / 4; i++)
{
iAcc += (m_samplesDB[a][0] + m_samplesDB[b][0]) * HBFIRFilterTraits<HBFilterOrder>::hbCoeffsF[i];
qAcc += (m_samplesDB[a][1] + m_samplesDB[b][1]) * HBFIRFilterTraits<HBFilterOrder>::hbCoeffsF[i];
a -= 2;
b += 2;
}
iAcc += m_samplesDB[b-1][0] << (HBFIRFilterTraits<HBFilterOrder>::hbShift - 1);
qAcc += m_samplesDB[b-1][1] << (HBFIRFilterTraits<HBFilterOrder>::hbShift - 1);
sample->setReal(iAcc*SDR_RX_SCALED);
sample->setImag(qAcc*SDR_RX_SCALED);
}
void doFIRAccu(AccuType *x, AccuType *y)
{
int a = m_ptr + m_size; // tip pointer
int b = m_ptr + 1; // tail pointer
AccuType iAcc = 0;
AccuType qAcc = 0;
for (int i = 0; i < HBFIRFilterTraits<HBFilterOrder>::hbOrder / 4; i++)
{
iAcc += (m_samplesDB[a][0] + m_samplesDB[b][0]) * HBFIRFilterTraits<HBFilterOrder>::hbCoeffsF[i];
qAcc += (m_samplesDB[a][1] + m_samplesDB[b][1]) * HBFIRFilterTraits<HBFilterOrder>::hbCoeffsF[i];
a -= 2;
b += 2;
}
iAcc += m_samplesDB[b-1][0] / 2.0;
qAcc += m_samplesDB[b-1][1] / 2.0;
*x = iAcc; // HB_SHIFT incorrect do not loose the gained bit
*y = qAcc;
}
void doInterpolateFIR(Sample* sample)
{
qint16 a = m_ptr;
qint16 b = m_ptr + (HBFIRFilterTraits<HBFilterOrder>::hbOrder / 2) - 1;
// go through samples in buffer
AccuType iAcc = 0;
AccuType qAcc = 0;
for (int i = 0; i < HBFIRFilterTraits<HBFilterOrder>::hbOrder / 4; i++)
{
iAcc += (m_samplesDB[a][0] + m_samplesDB[b][0]) * HBFIRFilterTraits<HBFilterOrder>::hbCoeffsF[i];
qAcc += (m_samplesDB[a][1] + m_samplesDB[b][1]) * HBFIRFilterTraits<HBFilterOrder>::hbCoeffsF[i];
a++;
b--;
}
sample->setReal(iAcc * SDR_RX_SCALED);
sample->setImag(qAcc * SDR_RX_SCALED);
}
void doInterpolateFIR(qint32 *x, qint32 *y)
{
qint16 a = m_ptr;
qint16 b = m_ptr + (HBFIRFilterTraits<HBFilterOrder>::hbOrder / 2) - 1;
// go through samples in buffer
AccuType iAcc = 0;
AccuType qAcc = 0;
for (int i = 0; i < HBFIRFilterTraits<HBFilterOrder>::hbOrder / 4; i++)
{
iAcc += (m_samplesDB[a][0] + m_samplesDB[b][0]) * HBFIRFilterTraits<HBFilterOrder>::hbCoeffsF[i];
qAcc += (m_samplesDB[a][1] + m_samplesDB[b][1]) * HBFIRFilterTraits<HBFilterOrder>::hbCoeffsF[i];
a++;
b--;
}
*x = iAcc * SDR_RX_SCALED;
*y = qAcc * SDR_RX_SCALED;
}
};
template<typename AccuType, typename SampleType, uint32_t HBFilterOrder>
IntHalfbandFilterDBF<AccuType, SampleType, HBFilterOrder>::IntHalfbandFilterDBF()
{
m_size = HBFIRFilterTraits<HBFilterOrder>::hbOrder - 1;
for (int i = 0; i < m_size; i++)
{
m_samplesDB[i][0] = 0;
m_samplesDB[i][1] = 0;
}
m_ptr = 0;
m_state = 0;
}
#endif // INCLUDE_INTHALFBANDFILTER_DBF_H
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