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AM demod: implemented low pass filter after the demod

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This commit is contained in:
f4exb 2019-05-29 11:23:28 +02:00
parent 9bd9c805de
commit d2c31059dd
2 changed files with 7 additions and 0 deletions
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6
plugins/channelrx/demodam/amdemod.cpp
View File

@ -260,6 +260,10 @@ void AMDemod::processOneSample(Complex &ci)
demod = m_bandpass.filter(demod); demod = m_bandpass.filter(demod);
demod /= 301.0f; demod /= 301.0f;
} }
else
{
demod = m_lowpass.filter(demod);
}
Real attack = (m_squelchCount - 0.05f * m_audioSampleRate) / (0.05f * m_audioSampleRate); Real attack = (m_squelchCount - 0.05f * m_audioSampleRate) / (0.05f * m_audioSampleRate);
sample = demod * StepFunctions::smootherstep(attack) * (m_audioSampleRate/24) * m_settings.m_volume; sample = demod * StepFunctions::smootherstep(attack) * (m_audioSampleRate/24) * m_settings.m_volume;
@ -383,6 +387,7 @@ void AMDemod::applyAudioSampleRate(int sampleRate)
m_interpolatorDistanceRemain = 0; m_interpolatorDistanceRemain = 0;
m_interpolatorDistance = (Real) m_inputSampleRate / (Real) sampleRate; m_interpolatorDistance = (Real) m_inputSampleRate / (Real) sampleRate;
m_bandpass.create(301, sampleRate, 300.0, m_settings.m_rfBandwidth / 2.0f); m_bandpass.create(301, sampleRate, 300.0, m_settings.m_rfBandwidth / 2.0f);
m_lowpass.create(301, sampleRate, m_settings.m_rfBandwidth / 2.0f);
m_audioFifo.setSize(sampleRate); m_audioFifo.setSize(sampleRate);
m_squelchDelayLine.resize(sampleRate/5); m_squelchDelayLine.resize(sampleRate/5);
DSBFilter->create_dsb_filter((2.0f * m_settings.m_rfBandwidth) / (float) sampleRate); DSBFilter->create_dsb_filter((2.0f * m_settings.m_rfBandwidth) / (float) sampleRate);
@ -456,6 +461,7 @@ void AMDemod::applySettings(const AMDemodSettings& settings, bool force)
m_interpolatorDistanceRemain = 0; m_interpolatorDistanceRemain = 0;
m_interpolatorDistance = (Real) m_inputSampleRate / (Real) m_audioSampleRate; m_interpolatorDistance = (Real) m_inputSampleRate / (Real) m_audioSampleRate;
m_bandpass.create(301, m_audioSampleRate, 300.0, settings.m_rfBandwidth / 2.0f); m_bandpass.create(301, m_audioSampleRate, 300.0, settings.m_rfBandwidth / 2.0f);
m_lowpass.create(301, m_audioSampleRate, m_settings.m_rfBandwidth / 2.0f);
DSBFilter->create_dsb_filter((2.0f * settings.m_rfBandwidth) / (float) m_audioSampleRate); DSBFilter->create_dsb_filter((2.0f * settings.m_rfBandwidth) / (float) m_audioSampleRate);
m_settingsMutex.unlock(); m_settingsMutex.unlock();

1
plugins/channelrx/demodam/amdemod.h
View File

@ -207,6 +207,7 @@ private:
MovingAverageUtil<Real, double, 16> m_movingAverage; MovingAverageUtil<Real, double, 16> m_movingAverage;
SimpleAGC<4800> m_volumeAGC; SimpleAGC<4800> m_volumeAGC;
Bandpass<Real> m_bandpass; Bandpass<Real> m_bandpass;
Lowpass<Real> m_lowpass;
Lowpass<std::complex<float> > m_pllFilt; Lowpass<std::complex<float> > m_pllFilt;
PhaseLockComplex m_pll; PhaseLockComplex m_pll;
fftfilt* DSBFilter; fftfilt* DSBFilter;