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sdrangel/sdrbase/dsp/inthalfbandfilterdb.h

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Tx ph.2: put the double buffered FIR interpolator and decimator in its own class
2016-11-01 10:02:50 -04:00
///////////////////////////////////////////////////////////////////////////////////
// Copyright (C) 2016 F4EXB //
// written by Edouard Griffiths //
// //
// Integer 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_DB_H
#define INCLUDE_INTHALFBANDFILTER_DB_H
#include <stdint.h>
#include "dsp/dsptypes.h"
#include "dsp/hbfiltertraits.h"
#include "util/export.h"
template<uint32_t HBFilterOrder>
class SDRANGEL_API IntHalfbandFilterDB {
public:
IntHalfbandFilterDB();
// downsample by 2, return center part of original spectrum
bool workDecimateCenter(Sample* sample)
{
// insert sample into ring-buffer
m_samplesDB[m_ptrDB][0] = sample->real();
m_samplesDB[m_ptrDB][1] = sample->imag();
m_samplesDB[m_ptrDB + m_sizeDB][0] = sample->real();
m_samplesDB[m_ptrDB + m_sizeDB][1] = sample->imag();
switch(m_state)
{
case 0:
// advance write-pointer
m_ptrDB = (m_ptrDB + 1) % m_sizeDB;
// next state
m_state = 1;
// tell caller we don't have a new sample
return false;
default:
// save result
doFIR(sample);
// advance write-pointer
m_ptrDB = (m_ptrDB + 1) % m_sizeDB;
// 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 workInterpolateCenter(Sample* sampleIn, Sample *SampleOut)
{
switch(m_state)
{
case 0:
// insert sample into ring-buffer
m_samplesDB[m_ptrDB][0] = 0;
m_samplesDB[m_ptrDB][1] = 0;
m_samplesDB[m_ptrDB + m_sizeDB][0] = 0;
m_samplesDB[m_ptrDB + m_sizeDB][1] = 0;
// save result
doFIR(SampleOut);
// advance write-pointer
m_ptrDB = (m_ptrDB + 1) % m_sizeDB;
// next state
m_state = 1;
// tell caller we didn't consume the sample
return false;
default:
// insert sample into ring-buffer
m_samplesDB[m_ptrDB][0] = sampleIn->real();
m_samplesDB[m_ptrDB][1] = sampleIn->imag();
m_samplesDB[m_ptrDB + m_sizeDB][0] = sampleIn->real();
m_samplesDB[m_ptrDB + m_sizeDB][1] = sampleIn->imag();
// save result
doFIR(SampleOut);
// advance write-pointer
m_ptrDB = (m_ptrDB + 1) % m_sizeDB;
// next state
m_state = 0;
// tell caller we consumed the sample
return true;
}
}
bool workDecimateCenter(qint32 *x, qint32 *y)
{
// insert sample into ring-buffer
m_samplesDB[m_ptrDB][0] = *x;
m_samplesDB[m_ptrDB][1] = *y;
m_samplesDB[m_ptrDB + m_sizeDB][0] = *x;
m_samplesDB[m_ptrDB + m_sizeDB][1] = *y;
switch(m_state)
{
case 0:
// advance write-pointer
m_ptrDB = (m_ptrDB + 1) % m_sizeDB;
// next state
m_state = 1;
// tell caller we don't have a new sample
return false;
default:
// save result
doFIR(x, y);
// advance write-pointer
m_ptrDB = (m_ptrDB + 1) % m_sizeDB;
// next state
m_state = 0;
// tell caller we have a new sample
return true;
}
}
// downsample by 2, return lower half of original spectrum
bool workDecimateLowerHalf(Sample* sample)
{
switch(m_state)
{
case 0:
// insert sample into ring-buffer
m_samplesDB[m_ptrDB][0] = -sample->imag();
m_samplesDB[m_ptrDB][1] = sample->real();
m_samplesDB[m_ptrDB + m_sizeDB][0] = -sample->imag();
m_samplesDB[m_ptrDB + m_sizeDB][1] = sample->real();
// advance write-pointer
m_ptrDB = (m_ptrDB + 1) % m_sizeDB;
// next state
m_state = 1;
// tell caller we don't have a new sample
return false;
case 1:
// insert sample into ring-buffer
m_samplesDB[m_ptrDB][0] = -sample->real();
m_samplesDB[m_ptrDB][1] = -sample->imag();
m_samplesDB[m_ptrDB + m_sizeDB][0] = -sample->real();
m_samplesDB[m_ptrDB + m_sizeDB][1] = -sample->imag();
// save result
doFIR(sample);
// advance write-pointer
m_ptrDB = (m_ptrDB + 1) % m_sizeDB;
// next state
m_state = 2;
// tell caller we have a new sample
return true;
case 2:
// insert sample into ring-buffer
m_samplesDB[m_ptrDB][0] = sample->imag();
m_samplesDB[m_ptrDB][1] = -sample->real();
m_samplesDB[m_ptrDB + m_sizeDB][0] = sample->imag();
m_samplesDB[m_ptrDB + m_sizeDB][1] = -sample->real();
// advance write-pointer
m_ptrDB = (m_ptrDB + 1) % m_sizeDB;
// next state
m_state = 3;
// tell caller we don't have a new sample
return false;
default:
// insert sample into ring-buffer
m_samplesDB[m_ptrDB][0] = sample->real();
m_samplesDB[m_ptrDB][1] = sample->imag();
m_samplesDB[m_ptrDB + m_sizeDB][0] = sample->real();
m_samplesDB[m_ptrDB + m_sizeDB][1] = sample->imag();
// save result
doFIR(sample);
// advance write-pointer
m_ptrDB = (m_ptrDB + 1) % m_sizeDB;
// next state
m_state = 0;
// tell caller we have a new sample
return true;
}
}
// upsample by 2, from lower half of original spectrum - double buffer variant
bool workInterpolateLowerHalf(Sample* sampleIn, Sample *sampleOut)
{
Sample s;
switch(m_state)
{
case 0:
// insert sample into ring-buffer
m_samplesDB[m_ptrDB][0] = 0;
m_samplesDB[m_ptrDB][1] = 0;
m_samplesDB[m_ptrDB + m_sizeDB][0] = 0;
m_samplesDB[m_ptrDB + m_sizeDB][1] = 0;
// save result
doFIR(&s);
sampleOut->setReal(s.imag());
sampleOut->setImag(-s.real());
// advance write-pointer
m_ptrDB = (m_ptrDB + 1) % m_sizeDB;
// next state
m_state = 1;
// tell caller we didn't consume the sample
return false;
case 1:
// insert sample into ring-buffer
m_samplesDB[m_ptrDB][0] = sampleIn->real();
m_samplesDB[m_ptrDB][1] = sampleIn->imag();
m_samplesDB[m_ptrDB + m_sizeDB][0] = sampleIn->real();
m_samplesDB[m_ptrDB + m_sizeDB][1] = sampleIn->imag();
// save result
doFIR(&s);
sampleOut->setReal(-s.real());
sampleOut->setImag(-s.imag());
// advance write-pointer
m_ptrDB = (m_ptrDB + 1) % m_sizeDB;
// next state
m_state = 2;
// tell caller we consumed the sample
return true;
case 2:
// insert sample into ring-buffer
m_samplesDB[m_ptrDB][0] = 0;
m_samplesDB[m_ptrDB][1] = 0;
m_samplesDB[m_ptrDB + m_sizeDB][0] = 0;
m_samplesDB[m_ptrDB + m_sizeDB][1] = 0;
// save result
doFIR(&s);
sampleOut->setReal(-s.imag());
sampleOut->setImag(s.real());
// advance write-pointer
m_ptrDB = (m_ptrDB + 1) % m_sizeDB;
// next state
m_state = 3;
// tell caller we didn't consume the sample
return false;
default:
// insert sample into ring-buffer
m_samplesDB[m_ptrDB][0] = sampleIn->real();
m_samplesDB[m_ptrDB][1] = sampleIn->imag();
m_samplesDB[m_ptrDB + m_sizeDB][0] = sampleIn->real();
m_samplesDB[m_ptrDB + m_sizeDB][1] = sampleIn->imag();
// save result
doFIR(&s);
sampleOut->setReal(s.real());
sampleOut->setImag(s.imag());
// advance write-pointer
m_ptrDB = (m_ptrDB + 1) % m_sizeDB;
// 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
m_samplesDB[m_ptrDB][0] = sample->imag();
m_samplesDB[m_ptrDB][1] = -sample->real();
m_samplesDB[m_ptrDB + m_sizeDB][0] = sample->imag();
m_samplesDB[m_ptrDB + m_sizeDB][1] = -sample->real();
// advance write-pointer
m_ptrDB = (m_ptrDB + 1) % m_sizeDB;
// next state
m_state = 1;
// tell caller we don't have a new sample
return false;
case 1:
// insert sample into ring-buffer
m_samplesDB[m_ptrDB][0] = -sample->real();
m_samplesDB[m_ptrDB][1] = -sample->imag();
m_samplesDB[m_ptrDB + m_sizeDB][0] = -sample->real();
m_samplesDB[m_ptrDB + m_sizeDB][1] = -sample->imag();
// save result
doFIR(sample);
// advance write-pointer
m_ptrDB = (m_ptrDB + 1) % m_sizeDB;
// next state
m_state = 2;
// tell caller we have a new sample
return true;
case 2:
// insert sample into ring-buffer
m_samplesDB[m_ptrDB][0] = -sample->imag();
m_samplesDB[m_ptrDB][1] = sample->real();
m_samplesDB[m_ptrDB + m_sizeDB][0] = -sample->imag();
m_samplesDB[m_ptrDB + m_sizeDB][1] = sample->real();
// advance write-pointer
m_ptrDB = (m_ptrDB + 1) % m_sizeDB;
// next state
m_state = 3;
// tell caller we don't have a new sample
return false;
default:
// insert sample into ring-buffer
m_samplesDB[m_ptrDB][0] = sample->real();
m_samplesDB[m_ptrDB][1] = sample->imag();
m_samplesDB[m_ptrDB + m_sizeDB][0] = sample->real();
m_samplesDB[m_ptrDB + m_sizeDB][1] = sample->imag();
// save result
doFIR(sample);
// advance write-pointer
m_ptrDB = (m_ptrDB + 1) % m_sizeDB;
// next state
m_state = 0;
// tell caller we have a new sample
return true;
}
}
// upsample by 2, move original spectrum to upper half - double buffer variant
bool workInterpolateUpperHalf(Sample* sampleIn, Sample *sampleOut)
{
Sample s;
switch(m_state)
{
case 0:
// insert sample into ring-buffer
m_samplesDB[m_ptrDB][0] = 0;
m_samplesDB[m_ptrDB][1] = 0;
m_samplesDB[m_ptrDB + m_sizeDB][0] = 0;
m_samplesDB[m_ptrDB + m_sizeDB][1] = 0;
// save result
doFIR(&s);
sampleOut->setReal(-s.imag());
sampleOut->setImag(s.real());
// advance write-pointer
m_ptrDB = (m_ptrDB + 1) % m_sizeDB;
// next state
m_state = 1;
// tell caller we didn't consume the sample
return false;
case 1:
// insert sample into ring-buffer
m_samplesDB[m_ptrDB][0] = sampleIn->real();
m_samplesDB[m_ptrDB][1] = sampleIn->imag();
m_samplesDB[m_ptrDB + m_sizeDB][0] = sampleIn->real();
m_samplesDB[m_ptrDB + m_sizeDB][1] = sampleIn->imag();
// save result
doFIR(&s);
sampleOut->setReal(-s.real());
sampleOut->setImag(-s.imag());
// advance write-pointer
m_ptrDB = (m_ptrDB + 1) % m_sizeDB;
// next state
m_state = 2;
// tell caller we consumed the sample
return true;
case 2:
// insert sample into ring-buffer
m_samplesDB[m_ptrDB][0] = 0;
m_samplesDB[m_ptrDB][1] = 0;
m_samplesDB[m_ptrDB + m_sizeDB][0] = 0;
m_samplesDB[m_ptrDB + m_sizeDB][1] = 0;
// save result
doFIR(&s);
sampleOut->setReal(s.imag());
sampleOut->setImag(-s.real());
// advance write-pointer
m_ptrDB = (m_ptrDB + 1) % m_sizeDB;
// next state
m_state = 3;
// tell caller we didn't consume the sample
return false;
default:
// insert sample into ring-buffer
m_samplesDB[m_ptrDB][0] = sampleIn->real();
m_samplesDB[m_ptrDB][1] = sampleIn->imag();
m_samplesDB[m_ptrDB + m_sizeDB][0] = sampleIn->real();
m_samplesDB[m_ptrDB + m_sizeDB][1] = sampleIn->imag();
// save result
doFIR(&s);
sampleOut->setReal(s.real());
sampleOut->setImag(s.imag());
// advance write-pointer
m_ptrDB = (m_ptrDB + 1) % m_sizeDB;
// next state
m_state = 0;
// tell caller we consumed the sample
return true;
}
}
void myDecimate(const Sample* sample1, Sample* sample2)
{
m_samplesDB[m_ptrDB][0] = sample1->real();
m_samplesDB[m_ptrDB][1] = sample1->imag();
m_samplesDB[m_ptrDB + m_sizeDB][0] = sample1->real();
m_samplesDB[m_ptrDB + m_sizeDB][1] = sample1->imag();
m_ptrDB = (m_ptrDB + 1) % m_sizeDB;
m_samplesDB[m_ptrDB][0] = sample2->real();
m_samplesDB[m_ptrDB][1] = sample2->imag();
m_samplesDB[m_ptrDB + m_sizeDB][0] = sample2->real();
m_samplesDB[m_ptrDB + m_sizeDB][1] = sample2->imag();
doFIR(sample2);
m_ptrDB = (m_ptrDB + 1) % m_sizeDB;
}
void myDecimate(qint32 x1, qint32 y1, qint32 *x2, qint32 *y2)
{
m_samplesDB[m_ptrDB][0] = x1;
m_samplesDB[m_ptrDB][1] = y1;
m_samplesDB[m_ptrDB + m_sizeDB][0] = x1;
m_samplesDB[m_ptrDB + m_sizeDB][1] = y1;
m_ptrDB = (m_ptrDB + 1) % m_sizeDB;
m_samplesDB[m_ptrDB][0] = *x2;
m_samplesDB[m_ptrDB][1] = *y2;
m_samplesDB[m_ptrDB + m_sizeDB][0] = *x2;
m_samplesDB[m_ptrDB + m_sizeDB][1] = *y2;
doFIR(x2, y2);
m_ptrDB = (m_ptrDB + 1) % m_sizeDB;
}
protected:
qint32 m_samplesDB[2*(HBFIRFilterTraits<HBFilterOrder>::hbOrder - 1)][2]; // double buffer technique
int m_ptrDB;
int m_sizeDB;
int m_state;
void doFIR(Sample* sample)
{
int a = m_ptrDB + m_sizeDB; // tip pointer
int b = m_ptrDB + 1; // tail pointer
qint32 iAcc = 0;
qint32 qAcc = 0;
for (int i = 0; i < HBFIRFilterTraits<HBFilterOrder>::hbOrder / 4; i++)
{
iAcc += (m_samplesDB[a][0] + m_samplesDB[b][0]) * HBFIRFilterTraits<HBFilterOrder>::hbCoeffs[i];
qAcc += (m_samplesDB[a][1] + m_samplesDB[b][1]) * HBFIRFilterTraits<HBFilterOrder>::hbCoeffs[i];
a -= 2;
b += 2;
}
iAcc += ((qint32)m_samplesDB[b-1][0]) << (HBFIRFilterTraits<HBFilterOrder>::hbShift - 1);
qAcc += ((qint32)m_samplesDB[b-1][1]) << (HBFIRFilterTraits<HBFilterOrder>::hbShift - 1);
sample->setReal(iAcc >> HBFIRFilterTraits<HBFilterOrder>::hbShift -1);
sample->setImag(qAcc >> HBFIRFilterTraits<HBFilterOrder>::hbShift -1);
}
void doFIR(qint32 *x, qint32 *y)
{
int a = m_ptrDB + m_sizeDB; // tip pointer
int b = m_ptrDB + 1; // tail pointer
qint32 iAcc = 0;
qint32 qAcc = 0;
for (int i = 0; i < HBFIRFilterTraits<HBFilterOrder>::hbOrder / 4; i++)
{
iAcc += (m_samplesDB[a][0] + m_samplesDB[b][0]) * HBFIRFilterTraits<HBFilterOrder>::hbCoeffs[i];
qAcc += (m_samplesDB[a][1] + m_samplesDB[b][1]) * HBFIRFilterTraits<HBFilterOrder>::hbCoeffs[i];
a -= 2;
b += 2;
}
iAcc += ((qint32)m_samplesDB[b-1][0]) << (HBFIRFilterTraits<HBFilterOrder>::hbShift - 1);
qAcc += ((qint32)m_samplesDB[b-1][1]) << (HBFIRFilterTraits<HBFilterOrder>::hbShift - 1);
*x = iAcc >> (HBFIRFilterTraits<HBFilterOrder>::hbShift -1); // HB_SHIFT incorrect do not loose the gained bit
*y = qAcc >> (HBFIRFilterTraits<HBFilterOrder>::hbShift -1);
}
};
template<uint32_t HBFilterOrder>
IntHalfbandFilterDB<HBFilterOrder>::IntHalfbandFilterDB()
{
m_sizeDB = HBFIRFilterTraits<HBFilterOrder>::hbOrder - 1;
for (int i = 0; i < m_sizeDB; i++)
{
m_samplesDB[i][0] = 0;
m_samplesDB[i][1] = 0;
}
m_ptrDB = 0;
m_state = 0;
}
#endif // INCLUDE_INTHALFBANDFILTER_DB_H
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