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Corrected NFM demod. Implemented phase discriminator object in WFM demod

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This commit is contained in:
f4exb 2015-12-17 01:01:22 +01:00
parent 3028357718
commit 90552271f8
6 changed files with 16 additions and 11 deletions
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2
include/dsp/phasediscri.hpp → include/dsp/phasediscri.h
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@ -18,6 +18,8 @@
#ifndef INCLUDE_DSP_PHASEDISCRI_H_ #ifndef INCLUDE_DSP_PHASEDISCRI_H_
#define INCLUDE_DSP_PHASEDISCRI_H_ #define INCLUDE_DSP_PHASEDISCRI_H_
#include "dsp/dsptypes.h"
class PhaseDiscriminators class PhaseDiscriminators
{ {
public: public:

3
plugins/channel/nfm/nfmdemod.cpp
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@ -331,6 +331,7 @@ void NFMDemod::apply()
m_interpolator.create(16, m_config.m_inputSampleRate, m_config.m_rfBandwidth / 2.2); m_interpolator.create(16, m_config.m_inputSampleRate, m_config.m_rfBandwidth / 2.2);
m_interpolatorDistanceRemain = 0; m_interpolatorDistanceRemain = 0;
m_interpolatorDistance = (Real) m_config.m_inputSampleRate / (Real) m_config.m_audioSampleRate; m_interpolatorDistance = (Real) m_config.m_inputSampleRate / (Real) m_config.m_audioSampleRate;
m_fmExcursion = m_config.m_rfBandwidth / 2.0f;
m_phaseDiscri.setFMScaling(m_config.m_inputSampleRate / m_fmExcursion); m_phaseDiscri.setFMScaling(m_config.m_inputSampleRate / m_fmExcursion);
m_settingsMutex.unlock(); m_settingsMutex.unlock();
} }
@ -341,8 +342,6 @@ void NFMDemod::apply()
m_settingsMutex.lock(); m_settingsMutex.lock();
m_lowpass.create(301, m_config.m_audioSampleRate, 250.0); m_lowpass.create(301, m_config.m_audioSampleRate, 250.0);
m_bandpass.create(301, m_config.m_audioSampleRate, 300.0, m_config.m_afBandwidth); m_bandpass.create(301, m_config.m_audioSampleRate, 300.0, m_config.m_afBandwidth);
m_fmExcursion = m_config.m_afBandwidth / 2.0f;
m_phaseDiscri.setFMScaling(m_config.m_inputSampleRate / m_fmExcursion);
m_settingsMutex.unlock(); m_settingsMutex.unlock();
} }

2
plugins/channel/nfm/nfmdemod.h
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@ -18,6 +18,7 @@
#ifndef INCLUDE_NFMDEMOD_H #ifndef INCLUDE_NFMDEMOD_H
#define INCLUDE_NFMDEMOD_H #define INCLUDE_NFMDEMOD_H
#include <dsp/phasediscri.h>
#include <QMutex> #include <QMutex>
#include <vector> #include <vector>
#include "dsp/samplesink.h" #include "dsp/samplesink.h"
@ -29,7 +30,6 @@
#include "dsp/agc.h" #include "dsp/agc.h"
#include "dsp/ctcssdetector.h" #include "dsp/ctcssdetector.h"
#include "dsp/afsquelch.h" #include "dsp/afsquelch.h"
#include "dsp/phasediscri.hpp"
#include "audio/audiofifo.h" #include "audio/audiofifo.h"
#include "util/message.h" #include "util/message.h"

2
plugins/channel/nfm/nfmdemodgui.ui
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@ -244,7 +244,7 @@
<item> <item>
<widget class="QSlider" name="volume"> <widget class="QSlider" name="volume">
<property name="maximum"> <property name="maximum">
<number>40</number> <number>100</number>
</property> </property>
<property name="pageStep"> <property name="pageStep">
<number>1</number> <number>1</number>

12
plugins/channel/wfm/wfmdemod.cpp
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@ -42,6 +42,7 @@ WFMDemod::WFMDemod(SampleSink* sampleSink) :
m_config.m_volume = 2.0; m_config.m_volume = 2.0;
m_config.m_audioSampleRate = DSPEngine::instance()->getAudioSampleRate(); m_config.m_audioSampleRate = DSPEngine::instance()->getAudioSampleRate();
m_rfFilter = new fftfilt(-50000.0 / 384000.0, 50000.0 / 384000.0, rfFilterFftLength); m_rfFilter = new fftfilt(-50000.0 / 384000.0, 50000.0 / 384000.0, rfFilterFftLength);
m_phaseDiscri.setFMScaling(384000/75000);
apply(); apply();
@ -101,20 +102,19 @@ void WFMDemod::feed(const SampleVector::const_iterator& begin, const SampleVecto
// Alternative without atan // Alternative without atan
// http://www.embedded.com/design/configurable-systems/4212086/DSP-Tricks--Frequency-demodulation-algorithms- // http://www.embedded.com/design/configurable-systems/4212086/DSP-Tricks--Frequency-demodulation-algorithms-
// in addition it needs scaling by instantaneous magnitude squared and volume (0..10) adjustment factor // in addition it needs scaling by instantaneous magnitude squared and volume (0..10) adjustment factor
/*
Real ip = rf[i].real() - m_m2Sample.real(); Real ip = rf[i].real() - m_m2Sample.real();
Real qp = rf[i].imag() - m_m2Sample.imag(); Real qp = rf[i].imag() - m_m2Sample.imag();
Real h1 = m_m1Sample.real() * qp; Real h1 = m_m1Sample.real() * qp;
Real h2 = m_m1Sample.imag() * ip; Real h2 = m_m1Sample.imag() * ip;
demod = (h1 - h2) / (msq * 10.0); demod = (h1 - h2) / (msq * 10.0);*/
demod = m_phaseDiscri.phaseDiscriminator2(rf[i]);
} }
else else
{ {
demod = 0; demod = 0;
} }
m_m2Sample = m_m1Sample;
m_m1Sample = rf[i];
Complex e(demod, 0); Complex e(demod, 0);
if(m_interpolator.interpolate(&m_interpolatorDistanceRemain, e, &ci)) if(m_interpolator.interpolate(&m_interpolatorDistanceRemain, e, &ci))
@ -168,7 +168,7 @@ void WFMDemod::start()
{ {
m_squelchState = 0; m_squelchState = 0;
m_audioFifo.clear(); m_audioFifo.clear();
m_m1Sample = 0; m_phaseDiscri.reset();
} }
void WFMDemod::stop() void WFMDemod::stop()
@ -254,6 +254,8 @@ void WFMDemod::apply()
Real lowCut = -(m_config.m_rfBandwidth / 2.0) / m_config.m_inputSampleRate; Real lowCut = -(m_config.m_rfBandwidth / 2.0) / m_config.m_inputSampleRate;
Real hiCut = (m_config.m_rfBandwidth / 2.0) / m_config.m_inputSampleRate; Real hiCut = (m_config.m_rfBandwidth / 2.0) / m_config.m_inputSampleRate;
m_rfFilter->create_filter(lowCut, hiCut); m_rfFilter->create_filter(lowCut, hiCut);
m_fmExcursion = m_config.m_rfBandwidth / 2.0;
m_phaseDiscri.setFMScaling(m_config.m_inputSampleRate / m_fmExcursion);
m_settingsMutex.unlock(); m_settingsMutex.unlock();
} }

6
plugins/channel/wfm/wfmdemod.h
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@ -26,6 +26,7 @@
#include "dsp/lowpass.h" #include "dsp/lowpass.h"
#include "dsp/movingaverage.h" #include "dsp/movingaverage.h"
#include "dsp/fftfilt.h" #include "dsp/fftfilt.h"
#include "dsp/phasediscri.h"
#include "audio/audiofifo.h" #include "audio/audiofifo.h"
#include "util/message.h" #include "util/message.h"
@ -120,9 +121,8 @@ private:
int m_squelchState; int m_squelchState;
Real m_lastArgument; Real m_lastArgument;
Complex m_m1Sample; //!< x^-1 sample
Complex m_m2Sample; //!< x^-1 sample
MovingAverage<Real> m_movingAverage; MovingAverage<Real> m_movingAverage;
Real m_fmExcursion;
AudioVector m_audioBuffer; AudioVector m_audioBuffer;
uint m_audioBufferFill; uint m_audioBufferFill;
@ -132,6 +132,8 @@ private:
SampleVector m_sampleBuffer; SampleVector m_sampleBuffer;
QMutex m_settingsMutex; QMutex m_settingsMutex;
PhaseDiscriminators m_phaseDiscri;
void apply(); void apply();
}; };