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Tx ph.2: use a specialized interpolator similar to the decimator derived from the ancient interpolator

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This commit is contained in:
f4exb 2016-10-28 03:18:24 +02:00
parent 9540a99ac4
commit 4d273d8a13
4 changed files with 33 additions and 23 deletions
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25
plugins/channeltx/modam/ammod.cpp
View File

@ -65,17 +65,28 @@ void AMMod::pull(Sample& sample)
{
Complex ci;
m_interpolator.interpolate(&m_interpolatorDistanceRemain, m_modSample, &m_interpolatorConsumed, &ci);
m_interpolatorDistanceRemain += m_interpolatorDistance;
// Resampler used for interpolation only
// m_interpolator.resample(&m_interpolatorDistanceRemain, m_modSample, &m_interpolatorConsumed, &ci);
// m_interpolatorDistanceRemain += m_interpolatorDistance;
//
// if (m_interpolatorConsumed)
// {
// Real t = m_toneNco.next();
// m_modSample.real(((t+1.0f) * m_running.m_modFactor * 16384.0f)); // modulate and scale zero frequency carrier
// m_modSample.imag(0.0f);
// m_interpolatorConsumed = false;
// }
if (m_interpolatorConsumed)
// Specialized interpolator
if (m_interpolator.interpolate(&m_interpolatorDistanceRemain, m_modSample, &ci))
{
Real t = m_toneNco.next();
m_modSample.real(((t+1.0f) * m_running.m_modFactor * 16384.0f)); // modulate and scale zero frequency carrier
m_modSample.imag(0.0f);
m_interpolatorConsumed = false;
Real t = m_toneNco.next();
m_modSample.real(((t+1.0f) * m_running.m_modFactor * 16384.0f)); // modulate and scale zero frequency carrier
m_modSample.imag(0.0f);
}
m_interpolatorDistanceRemain += m_interpolatorDistance;
ci *= m_carrierNco.nextIQ(); // shift to carrier frequency
Real magsq = ci.real() * ci.real() + ci.imag() * ci.imag();

4
plugins/samplesink/filesink/filesinkgui.cpp
View File

@ -327,8 +327,8 @@ void FileSinkGui::tick()
}
}
unsigned int FileSinkSampleRates::m_rates[] = {48, 60, 64, 80};
unsigned int FileSinkSampleRates::m_nb_rates = 4;
unsigned int FileSinkSampleRates::m_rates[] = {48, 60, 60, 64, 72};
unsigned int FileSinkSampleRates::m_nb_rates = 5;
unsigned int FileSinkSampleRates::getRate(unsigned int rate_index)
{

2
plugins/samplesink/filesink/filesinkgui.h
View File

@ -93,7 +93,7 @@ public:
static unsigned int getRateIndex(unsigned int rate);
static unsigned int getNbRates();
private:
static unsigned int m_rates[4];
static unsigned int m_rates[5];
static unsigned int m_nb_rates;
};

25
sdrbase/dsp/interpolator.h
View File

@ -35,27 +35,26 @@ public:
return true;
}
// interpolation works nearly the same way // TODO: remove when original is used
// interpolation simplified from the generalized resampler
bool interpolate(Real *distance, const Complex& next, Complex* result)
{
*distance -= 1.0;
bool consumed = false;
if (*distance < 1.0) // use sample
if (*distance >= 1.0)
{
advanceFilter(next);
doInterpolate((int) floor(*distance * (Real)m_phaseSteps), result);
return true; // need new input sample and increment distance
}
else // use zero
{
advanceFilter();
doInterpolate((int) floor(*distance * (Real)m_phaseSteps), result);
return false; // input sample was not used and do not increment distance
*distance -= 1.0;
consumed = true;
}
doInterpolate((int)floor(*distance * (Real)m_phaseSteps), result);
return consumed;
}
// original interpolator
bool interpolate(Real* distance, const Complex& next, bool* consumed, Complex* result)
// original interpolator which is actually an arbitrary rational resampler P/Q for any positive P, Q
// sampling frequency must be the highest of the two
bool resample(Real* distance, const Complex& next, bool* consumed, Complex* result)
{
while(*distance >= 1.0)
{