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330 WIP on redesigning the P25 C4FM decoder. Creates a new decoder

Browse Source 
based on the P25 LSM decoder using a costas loop and a gardner detector.
Updates the Demodulator Viewer FX application to add in a symbol chart
and a phase error chart.  The decoder won't lock on yet ... still a wip.
This commit is contained in:
Denny
2018-02-17 13:41:36 -05:00
parent 80c5ad1bc8
commit eaf7c7d11e
47 changed files with 3926 additions and 2093 deletions
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21
src/main/java/io/github/dsheirer/dsp/filter/design/FilterViewer.java
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@@ -39,15 +39,24 @@ public class FilterViewer extends Application
*/
private float[] getFilter()
{
// FIRFilterSpecification specification = FIRFilterSpecification.lowPassBuilder()
// .sampleRate(48000)
// .gridDensity(16)
// .passBandCutoff(2500)
// .passBandAmplitude(1.0)
// .passBandRipple(0.01)
// .stopBandStart(4000)
// .stopBandAmplitude(0.0)
// .stopBandRipple(0.008)
// .build();
FIRFilterSpecification specification = FIRFilterSpecification.lowPassBuilder()
.sampleRate(48000)
.gridDensity(16)
.passBandCutoff(2500)
.sampleRate((int)48000.0)
.passBandCutoff(6000)
.passBandAmplitude(1.0)
.passBandRipple(0.01)
.stopBandStart(4000)
.passBandRipple(0.1)
.stopBandAmplitude(0.0)
.stopBandRipple(0.008)
.stopBandStart(6250)
.stopBandRipple(0.01)
.build();
// FIRFilterSpecification specification = FIRFilterSpecification.highPassBuilder()

126
src/main/java/io/github/dsheirer/dsp/filter/fir/complex/ComplexFIRFilter.java
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@@ -1,54 +1,90 @@
/*******************************************************************************
* sdr-trunk
* Copyright (C) 2014-2018 Dennis Sheirer
*
* 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, either version 3 of the License, or (at your option) any
* later version.
*
* 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 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/>
*
******************************************************************************/
package io.github.dsheirer.dsp.filter.fir.complex;
import io.github.dsheirer.dsp.filter.fir.FIRFilter;
import io.github.dsheirer.dsp.filter.fir.real.RealFIRFilter;
import io.github.dsheirer.sample.complex.Complex;
import io.github.dsheirer.sample.complex.ComplexBuffer;
public class ComplexFIRFilter extends FIRFilter
{
private RealFIRFilter mIFilter;
private RealFIRFilter mQFilter;
/**
* Complex FIR Filter for processing complex sample pairs. Wraps two real
* FIR filters for processing each of the inphase and quadrature samples.
*
* @param coefficients - filter taps
* @param gain - gain to apply to filtered outputs - use 1.0f for no gain
*/
public ComplexFIRFilter( float[] coefficients, float gain )
{
mIFilter = new RealFIRFilter( coefficients, gain );
mQFilter = new RealFIRFilter( coefficients, gain );
}
public float[] getCoefficients()
{
return mIFilter.getCoefficients();
}
public float filterInphase( float sample )
{
return mIFilter.filter( sample );
}
public float filterQuadrature( float sample )
{
return mQFilter.filter( sample );
}
public Complex filter( Complex sample )
{
float i = filterInphase( sample.inphase() );
float q = filterQuadrature( sample.quadrature() );
return new Complex( i, q );
}
@Override
public void dispose()
{
mIFilter.dispose();
mQFilter.dispose();
}
private RealFIRFilter mIFilter;
private RealFIRFilter mQFilter;
/**
* Complex FIR Filter for processing complex sample pairs. Wraps two real
* FIR filters for processing each of the inphase and quadrature samples.
*
* @param coefficients - filter taps
* @param gain - gain to apply to filtered outputs - use 1.0f for no gain
*/
public ComplexFIRFilter(float[] coefficients, float gain)
{
mIFilter = new RealFIRFilter(coefficients, gain);
mQFilter = new RealFIRFilter(coefficients, gain);
}
public float[] getCoefficients()
{
return mIFilter.getCoefficients();
}
public float filterInphase(float sample)
{
return mIFilter.filter(sample);
}
public float filterQuadrature(float sample)
{
return mQFilter.filter(sample);
}
public Complex filter(Complex sample)
{
float i = filterInphase(sample.inphase());
float q = filterQuadrature(sample.quadrature());
return new Complex(i, q);
}
/**
* Filters the complex samples from the buffer and returns a new complex buffer with the filtered output
*
* @param buffer with complex samples to filter
* @return new buffer containing filtered complex samples
*/
public ComplexBuffer filter(ComplexBuffer buffer)
{
float[] samples = buffer.getSamples();
float[] filtered = new float[samples.length];
for(int x = 0; x < samples.length; x += 2)
{
filtered[x] = filterInphase(samples[x]);
filtered[x + 1] = filterQuadrature(samples[x + 1]);
}
return new ComplexBuffer(filtered);
}
@Override
public void dispose()
{
mIFilter.dispose();
mQFilter.dispose();
}
}

3
src/main/java/io/github/dsheirer/dsp/filter/fir/complex/ComplexFIRFilter_CB_CB.java
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@@ -3,8 +3,7 @@ package io.github.dsheirer.dsp.filter.fir.complex;
import io.github.dsheirer.sample.Listener;
import io.github.dsheirer.sample.complex.ComplexBuffer;
public class ComplexFIRFilter_CB_CB extends ComplexFIRFilter
implements Listener<ComplexBuffer>
public class ComplexFIRFilter_CB_CB extends ComplexFIRFilter implements Listener<ComplexBuffer>
{
private Listener<ComplexBuffer> mListener;

205
src/main/java/io/github/dsheirer/dsp/gain/ComplexFeedForwardGainControl.java
View File

@@ -1,112 +1,125 @@
/*******************************************************************************
* sdr-trunk
* Copyright (C) 2014-2018 Dennis Sheirer
*
* 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, either version 3 of the License, or (at your option) any
* later version.
*
* 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 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/>
*
******************************************************************************/
package io.github.dsheirer.dsp.gain;
import io.github.dsheirer.buffer.FloatCircularBuffer;
import io.github.dsheirer.sample.complex.Complex;
import io.github.dsheirer.sample.complex.ComplexBuffer;
import io.github.dsheirer.sample.complex.ComplexSampleListener;
/*******************************************************************************
* SDR Trunk
* Copyright (C) 2015 Dennis Sheirer
*
* 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, either version 3 of the License, or
* (at your option) any later version.
*
* 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 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/>
*
* This class is modeled using concepts detailed in the GNURadio
* implementation of feed forward AGC class located at:
* https://github.com/gnuradio/gnuradio/blob/master/gr-analog/lib/
* feedforward_agc_cc_impl.cc
*
******************************************************************************/
public class ComplexFeedForwardGainControl implements ComplexSampleListener
{
public static final float OBJECTIVE_ENVELOPE = 1.0f;
public static final float MINIMUM_ENVELOPE = 0.0001f;
public static final float OBJECTIVE_ENVELOPE = 1.0f;
public static final float MINIMUM_ENVELOPE = 0.0001f;
private ComplexSampleListener mListener;
private ComplexSampleListener mListener;
private FloatCircularBuffer mEnvelopeHistory;
private float mMaxEnvelope = 0.0f;
private float mGain = 1.0f;
/**
* Dynamic gain control for incoming sample stream to amplify or attenuate
* all samples toward an objective unity)gain, using the maximum envelope
* value detected in the stream history window.
*
* Uses the specified damping factor to limit gain swings. Damping factor
* is applied against the delta between current gain value and a recalculated
* gain value to limit how quickly the gain value will increase or decrease.
*
* @param window - history size to use in detecting maximum envelope value
* @param damping - a value between 0 < damping <= 1.0;
*/
public ComplexFeedForwardGainControl( int window )
{
mEnvelopeHistory = new FloatCircularBuffer( window );
}
public void dispose()
{
mListener = null;
}
private FloatCircularBuffer mEnvelopeHistory;
@Override
public void receive( float inphase, float quadrature )
{
float envelope = Complex.envelope( inphase, quadrature );
private float mMaxEnvelope = 0.0f;
private float mGain = 1.0f;
if( envelope > mMaxEnvelope )
{
mMaxEnvelope = envelope;
adjustGain();
}
/**
* Dynamic gain control for incoming sample stream to amplify or attenuate
* all samples toward an objective unity)gain, using the maximum envelope
* value detected in the stream history window.
*
* Uses the specified damping factor to limit gain swings. Damping factor
* is applied against the delta between current gain value and a recalculated
* gain value to limit how quickly the gain value will increase or decrease.
*
* @param window - history size to use in detecting maximum envelope value
*/
public ComplexFeedForwardGainControl(int window)
{
mEnvelopeHistory = new FloatCircularBuffer(window);
}
/* Replace oldest envelope value with current envelope value */
float oldestEnvelope = mEnvelopeHistory.get( envelope );
public void dispose()
{
mListener = null;
}
/* If the oldest envelope value was the max envelope value, then we
* have to rediscover the max value from the envelope history */
if( mMaxEnvelope == oldestEnvelope && mMaxEnvelope != envelope )
{
mMaxEnvelope = MINIMUM_ENVELOPE;
for( float value: mEnvelopeHistory.getBuffer() )
{
if( value > mMaxEnvelope )
{
mMaxEnvelope = value;
}
}
adjustGain();
}
/* Apply current gain value to the sample and send to the listener */
if( mListener != null )
{
mListener.receive( inphase *= mGain, quadrature *= mGain );
}
}
private void adjustGain()
{
mGain = OBJECTIVE_ENVELOPE / mMaxEnvelope;
}
@Override
public void receive(float inphase, float quadrature)
{
process(inphase, quadrature);
public void setListener( ComplexSampleListener listener )
{
mListener = listener;
}
/* Apply current gain value to the sample and send to the listener */
if(mListener != null)
{
mListener.receive(inphase *= mGain, quadrature *= mGain);
}
}
private void process(float inphase, float quadrature)
{
float envelope = Complex.envelope(inphase, quadrature);
if(envelope > mMaxEnvelope)
{
mMaxEnvelope = envelope;
adjustGain();
}
/* Replace oldest envelope value with current envelope value */
float oldestEnvelope = mEnvelopeHistory.get(envelope);
/* If the oldest envelope value was the max envelope value, then we
* have to rediscover the max value from the envelope history */
if(mMaxEnvelope == oldestEnvelope && mMaxEnvelope != envelope)
{
mMaxEnvelope = MINIMUM_ENVELOPE;
for(float value : mEnvelopeHistory.getBuffer())
{
if(value > mMaxEnvelope)
{
mMaxEnvelope = value;
}
}
adjustGain();
}
}
private void adjustGain()
{
mGain = OBJECTIVE_ENVELOPE / mMaxEnvelope;
}
public void setListener(ComplexSampleListener listener)
{
mListener = listener;
}
public ComplexBuffer filter(ComplexBuffer complexBuffer)
{
float[] samples = complexBuffer.getSamples();
float[] processed = new float[samples.length];
for(int x = 0; x < samples.length; x += 2)
{
process(samples[x], samples[x + 1]);
processed[x] = samples[x] * mGain;
processed[x + 1] = samples[x + 1] * mGain;
}
return new ComplexBuffer(processed);
}
}

3
src/main/java/io/github/dsheirer/dsp/mixer/Oscillator.java
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@@ -51,8 +51,7 @@ public class Oscillator
*/
private void update()
{
float anglePerSample =
(float)( 2.0d * Math.PI * mFrequency / mSampleRate );
float anglePerSample = (float)( 2.0d * Math.PI * mFrequency / mSampleRate );
mAnglePerSample = Complex.fromAngle( anglePerSample );
}

30
src/main/java/io/github/dsheirer/dsp/psk/DQPSKSymbolPhaseErrorCalculator.java Normal file
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@@ -0,0 +1,30 @@
/*******************************************************************************
* sdr-trunk
* Copyright (C) 2014-2018 Dennis Sheirer
*
* 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, either version 3 of the License, or (at your option) any
* later version.
*
* 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 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/>
*
******************************************************************************/
package io.github.dsheirer.dsp.psk;
import io.github.dsheirer.sample.complex.Complex;
public class DQPSKSymbolPhaseErrorCalculator extends QPSKSymbolPhaseErrorCalculator
{
//Negative 45 degrees rotation to offset for differential additive 45 degrees of rotation
public static final Complex DIFFERENTIAL_OFFSET = Complex.fromAngle(Math.PI / -4.0d);
@Override
public void adjust(Complex symbol)
{
symbol.multiply(DIFFERENTIAL_OFFSET);
}
}

82
src/main/java/io/github/dsheirer/dsp/psk/GardnerDetector.java Normal file
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@@ -0,0 +1,82 @@
/*******************************************************************************
* sdr-trunk
* Copyright (C) 2014-2018 Dennis Sheirer
*
* 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, either version 3 of the License, or (at your option) any
* later version.
*
* 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 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/>
*
******************************************************************************/
package io.github.dsheirer.dsp.psk;
import io.github.dsheirer.sample.complex.Complex;
public class GardnerDetector
{
private float mErrorInphase;
private float mErrorQuadrature;
private float mError;
/**
* Gardner detector for recovering symbol timing error.
*/
public GardnerDetector()
{
}
/**
* Calculates the symbol timing error by evaluating the previous, middle and current symbol instants.
*
* @param previous symbol
* @param middle symbol (ie midway between the previous and current)
* @param current symbol
* @return symbol timing error
*/
public float getError(Complex previous, Complex middle, Complex current)
{
mErrorInphase = (previous.inphase() - current.inphase()) * middle.inphase();
mErrorQuadrature = (previous.quadrature() - current.quadrature()) * middle.quadrature();
mError = normalize(mErrorInphase + mErrorQuadrature, 1.0f);
return mError;
}
/**
* Constrains timing error to +/- the maximum value and corrects any floating point invalid numbers
*/
public static float normalize(float error, float maximum)
{
if(Float.isNaN(error))
{
return 0.0f;
}
else
{
return clip(error, maximum);
}
}
/**
* Constrains value to the range of ( -maximum <> maximum )
*/
public static float clip(float value, float maximum)
{
if(value > maximum)
{
return maximum;
}
else if(value < -maximum)
{
return -maximum;
}
return value;
}
}

29
src/main/java/io/github/dsheirer/dsp/psk/IQPSKSymbolDecoder.java Normal file
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@@ -0,0 +1,29 @@
/*******************************************************************************
* sdr-trunk
* Copyright (C) 2014-2018 Dennis Sheirer
*
* 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, either version 3 of the License, or (at your option) any
* later version.
*
* 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 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/>
*
******************************************************************************/
package io.github.dsheirer.dsp.psk;
import io.github.dsheirer.dsp.symbol.Dibit;
import io.github.dsheirer.sample.complex.Complex;
public interface IQPSKSymbolDecoder
{
/**
* Decodes the symbol and converts it into a Dibit
* @param symbol to decode
* @return decoded dibit
*/
Dibit decode(Complex symbol);
}

35
src/main/java/io/github/dsheirer/dsp/psk/ISymbolPhaseErrorCalculator.java Normal file
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@@ -0,0 +1,35 @@
/*******************************************************************************
* sdr-trunk
* Copyright (C) 2014-2018 Dennis Sheirer
*
* 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, either version 3 of the License, or (at your option) any
* later version.
*
* 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 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/>
*
******************************************************************************/
package io.github.dsheirer.dsp.psk;
import io.github.dsheirer.sample.complex.Complex;
public interface ISymbolPhaseErrorCalculator
{
/**
* Adjusts the calculated symbol as necessary before calculating any phase error. This might be useful for
* differential encoding to remove a 45 degree rotational spin.
* @param symbol to adjust
*/
void adjust(Complex symbol);
/**
* Calculates the phase error of the symbol relative to an alignment for the constellation
* @param symbol to calculate error
* @return error value
*/
float getPhaseError(Complex symbol);
}

187
src/main/java/io/github/dsheirer/dsp/psk/InterpolatingSymbolBuffer.java Normal file
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@@ -0,0 +1,187 @@
/*******************************************************************************
* sdr-trunk
* Copyright (C) 2014-2018 Dennis Sheirer
*
* 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, either version 3 of the License, or (at your option) any
* later version.
*
* 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 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/>
*
******************************************************************************/
package io.github.dsheirer.dsp.psk;
import io.github.dsheirer.dsp.filter.interpolator.RealInterpolator;
import io.github.dsheirer.sample.complex.Complex;
public class InterpolatingSymbolBuffer
{
private Complex mMiddleSample = new Complex(0,0);
private Complex mCurrentSample = new Complex(0,0);
private float[] mDelayLineInphase;
private float[] mDelayLineQuadrature;
private float mMu; //Sample Counter
private float mGainMu = 0.05f; //Sample Counter Gain
private float mOmega;
private float mGainOmega = 0.1f * mGainMu * mGainMu;
private float mOmegaRel = 0.005f;
private float mOmegaMid;
private int mDelayLinePointer = 0;
private int mTwiceSamplesPerSymbol;
private RealInterpolator mInterpolator = new RealInterpolator(1.0f);
public InterpolatingSymbolBuffer(float samplesPerSymbol)
{
mMu = samplesPerSymbol;
mTwiceSamplesPerSymbol = (int)Math.floor(2.0 * samplesPerSymbol);
mDelayLineInphase = new float[2 * mTwiceSamplesPerSymbol];
mDelayLineQuadrature = new float[2 * mTwiceSamplesPerSymbol];
mOmega = samplesPerSymbol;
mOmegaMid = samplesPerSymbol;
}
public void receive(Complex currentSample)
{
mMu--;
//Fill up the delay line to use with the interpolator
mDelayLineInphase[mDelayLinePointer] = currentSample.inphase();
mDelayLineInphase[mDelayLinePointer + mTwiceSamplesPerSymbol] = currentSample.inphase();
mDelayLineQuadrature[mDelayLinePointer] = currentSample.quadrature();
mDelayLineQuadrature[mDelayLinePointer + mTwiceSamplesPerSymbol] = currentSample.quadrature();
//Increment pointer and keep pointer in bounds
mDelayLinePointer = (mDelayLinePointer + 1) % mTwiceSamplesPerSymbol;
}
/**
* Updates the internal sample counter with additional samples to add to the symbol sample counter.
* @param samplesToAdd to the sample counter
*/
public void increaseSampleCounter(float samplesToAdd)
{
mMu += samplesToAdd;
}
/**
* Adjusts samples per symbol and symbol timing counters and increments the sample counter to collect another
* symbol.
*
* @param symbolTimingError from a symbol timing error detector
*/
public void resetAndAdjust(float symbolTimingError)
{
//mOmega is samples per symbol and is constrained to floating between +/- .005 of the nominal samples per
//symbol
mOmega = mOmega + mGainOmega * symbolTimingError;
mOmega = mOmegaMid + clip(mOmega - mOmegaMid, mOmegaRel);
//Add another symbol's worth of samples to the counter and adjust timing based on gardner error
increaseSampleCounter((mOmega + (mGainMu * symbolTimingError)));
}
/**
* Indicates if this buffer has accumulated a enough samples to represent a full symbol
*/
public boolean hasSymbol()
{
return mMu < 1.0f;
}
/**
* Interpolated middle sample for the symbol. Note: this method should only be invoked after testing for a
* complete symbol with the hasSymbol() method.
*/
public Complex getMiddleSample()
{
/* Calculate interpolated middle sample and current sample */
mMiddleSample.setValues(getInphase(mMu), getQuadrature(mMu));
return mMiddleSample;
}
/**
* Interpolated current sample for the symbol. This sample represents the ideal symbol sampling point.
* Note: this method should only be invoked after testing for a complete symbol with the hasSymbol() method.
*/
public Complex getCurrentSample()
{
float half_omega = mOmega / 2.0f;
int half_sps = (int)Math.floor(half_omega);
float half_mu = mMu + half_omega - half_sps;
if(half_mu > 1.0)
{
half_mu -= 1.0;
half_sps += 1;
}
mCurrentSample.setValues(getInphase(half_mu, half_sps), getQuadrature(half_mu, half_sps));
return mCurrentSample;
}
/**
* Returns the interpolated inphase value for the specified offset
* @param interpolation into the buffer to calculate the interpolated sample
* @return inphase value of the interpolated sample
*/
public float getInphase(float interpolation)
{
return mInterpolator.filter(mDelayLineInphase, mDelayLinePointer, interpolation);
}
/**
* Returns the interpolated inphase value for the specified offset
* @param interpolation into the buffer to calculate the interpolated sample
* @return inphase value of the interpolated sample
*/
public float getInphase(float interpolation, int indexOffet)
{
return mInterpolator.filter(mDelayLineInphase, mDelayLinePointer + indexOffet, interpolation);
}
/**
* Returns the interpolated quadrature value for the specified offset
* @param interpolation into the buffer to calculate the interpolated sample
* @return quadrature value of the interpolated sample
*/
public float getQuadrature(float interpolation)
{
return mInterpolator.filter(mDelayLineQuadrature, mDelayLinePointer, interpolation);
}
/**
* Returns the interpolated quadrature value for the specified offset
* @param interpolation into the buffer to calculate the interpolated sample
* @return quadrature value of the interpolated sample
*/
public float getQuadrature(float interpolation, int indexOffset)
{
return mInterpolator.filter(mDelayLineQuadrature, mDelayLinePointer + indexOffset, interpolation);
}
/**
* Constrains value to the range of ( -maximum <> maximum )
*/
public static float clip(float value, float maximum)
{
if(value > maximum)
{
return maximum;
}
else if(value < -maximum)
{
return -maximum;
}
return value;
}
}

28
src/main/java/io/github/dsheirer/dsp/psk/LSMConstellationDecoder.java Normal file
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@@ -0,0 +1,28 @@
/*******************************************************************************
* sdr-trunk
* Copyright (C) 2014-2018 Dennis Sheirer
*
* 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, either version 3 of the License, or (at your option) any
* later version.
*
* 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 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/>
*
******************************************************************************/
package io.github.dsheirer.dsp.psk;
import io.github.dsheirer.dsp.symbol.Dibit;
import io.github.dsheirer.sample.complex.Complex;
public class LSMConstellationDecoder implements IQPSKSymbolDecoder
{
@Override
public Dibit decode(Complex symbol)
{
return null;
}
}

950
src/main/java/io/github/dsheirer/dsp/psk/LSMDemodulator.java
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182
src/main/java/io/github/dsheirer/dsp/psk/QPSKDemodulator.java Normal file
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@@ -0,0 +1,182 @@
/*******************************************************************************
* sdr-trunk
* Copyright (C) 2014-2018 Dennis Sheirer
*
* 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, either version 3 of the License, or (at your option) any
* later version.
*
* 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 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/>
*
******************************************************************************/
package io.github.dsheirer.dsp.psk;
import io.github.dsheirer.dsp.psk.pll.IPhaseLockedLoop;
import io.github.dsheirer.dsp.symbol.Dibit;
import io.github.dsheirer.sample.Listener;
import io.github.dsheirer.sample.complex.Complex;
import io.github.dsheirer.sample.complex.ComplexBuffer;
import io.github.dsheirer.sample.complex.ComplexSampleListener;
public class QPSKDemodulator implements ComplexSampleListener
{
private InterpolatingSymbolBuffer mInterpolatingSymbolBuffer;
private IPhaseLockedLoop mPLL;
private ISymbolPhaseErrorCalculator mSymbolPhaseErrorCalculator;
private IQPSKSymbolDecoder mQPSKSymbolDecoder;
private GardnerDetector mGardnerDetector = new GardnerDetector();
private Listener<Complex> mSymbolListener;
private Listener<Double> mPLLErrorListener;
private Listener<Dibit> mDibitListener;
private Complex mPreviousSample = new Complex(0, 0);
private Complex mPreviousMiddleSample = new Complex(0, 0);
private Complex mCurrentSample = new Complex(0, 0);
private Complex mMiddleSample = new Complex(0, 0);
private Complex mPreviousSymbol = new Complex(0, 0);
private Complex mMiddleSymbol = new Complex(0, 0);
private Complex mCurrentSymbol = new Complex(0, 0);
private float mPhaseError;
private float mSymbolTimingError;
/**
* Decoder for Quaternary Phase Shift Keying (QPSK) and Differential QPSK (DQPSK). This decoder uses both a
* phase-locked loop and a gardner symbol timing error detector to automatically align to the incoming carrier
* frequency and to adjust for any changes in symbol timing.
*
* @param phaseLockedLoop for tracking carrier frequency error
* @param symbolPhaseErrorCalculator to calculate symbol phase errors and optionally adjust for differential encoding
* @param symbolDecoder to decode demodulated symbols into dibits
* @param sampleRate of the incoming complex sample stream
* @param symbolRate of the decoded QPSK symbols.
*/
public QPSKDemodulator(IPhaseLockedLoop phaseLockedLoop, ISymbolPhaseErrorCalculator symbolPhaseErrorCalculator,
IQPSKSymbolDecoder symbolDecoder, double sampleRate, double symbolRate)
{
if(sampleRate < (symbolRate * 2))
{
throw new IllegalArgumentException("Sample rate [" + sampleRate +
"] must be at least 2 x symbol rate [" + symbolRate + "]");
}
mPLL = phaseLockedLoop;
mSymbolPhaseErrorCalculator = symbolPhaseErrorCalculator;
mQPSKSymbolDecoder = symbolDecoder;
float samplesPerSymbol = (float)(sampleRate / symbolRate);
mInterpolatingSymbolBuffer = new InterpolatingSymbolBuffer(samplesPerSymbol);
}
/**
* Submits a buffer containing complex samples for decoding
* @param complexBuffer with complex samples
*/
public void receive(ComplexBuffer complexBuffer)
{
float[] samples = complexBuffer.getSamples();
for(int x = 0; x < samples.length; x += 2)
{
receive(samples[x], samples[x + 1]);
}
}
/**
* Submits a complex sample for decoding.
* @param inphase value for the sample
* @param quadrature value for the sample
*/
@Override
public void receive(float inphase, float quadrature)
{
//Update current sample with values
mCurrentSample.setValues(inphase, quadrature);
//Mix current sample with costas loop to remove any rotation that is present from a mis-tuned carrier frequency
mCurrentSample.multiply(mPLL.incrementAndGetCurrentVector());
mInterpolatingSymbolBuffer.receive(mCurrentSample);
//Calculate the symbol once we've stored enough samples
if(mInterpolatingSymbolBuffer.hasSymbol())
{
//Get middle and current samples from the interpolating buffer
mMiddleSample = mInterpolatingSymbolBuffer.getMiddleSample();
mCurrentSample = mInterpolatingSymbolBuffer.getCurrentSample();
//Calculate middle and current symbols as the delta between the previous and current samples
mMiddleSymbol.setInphase(Complex.multiplyInphase(mMiddleSample.inphase(), mMiddleSample.quadrature(), mPreviousMiddleSample.inphase(), -mPreviousMiddleSample.quadrature()));
mMiddleSymbol.setQuadrature(Complex.multiplyQuadrature(mMiddleSample.inphase(), mMiddleSample.quadrature(), mPreviousMiddleSample.inphase(), -mPreviousMiddleSample.quadrature()));
mCurrentSymbol.setInphase(Complex.multiplyInphase(mCurrentSample.inphase(), mCurrentSample.quadrature(), mPreviousSample.inphase(), -mPreviousSample.quadrature()));
mCurrentSymbol.setQuadrature(Complex.multiplyQuadrature(mCurrentSample.inphase(), mCurrentSample.quadrature(), mPreviousSample.inphase(), -mPreviousSample.quadrature()));
//Set gain to unity before we calculate the error value
mMiddleSymbol.normalize();
mCurrentSymbol.normalize();
//Symbol timing error calculations
mSymbolTimingError = mGardnerDetector.getError(mPreviousSymbol, mMiddleSymbol, mCurrentSymbol);
mInterpolatingSymbolBuffer.resetAndAdjust(mSymbolTimingError);
//Store current samples/symbols to use for the next period
mPreviousSample.setValues(mCurrentSample);
mPreviousMiddleSample.setValues(mMiddleSample);
mPreviousSymbol.setValues(mCurrentSymbol);
//Adjust the current symbol as necessary (e.g. for differential encoding)
mSymbolPhaseErrorCalculator.adjust(mCurrentSymbol);
//Calculate the phase error of the current symbol relative to the expected constellation and provide
//feedback to the PLL
mPhaseError = mSymbolPhaseErrorCalculator.getPhaseError(mCurrentSymbol);
mPLL.adjust(mPhaseError);
if(mPLLErrorListener != null)
{
mPLLErrorListener.receive((double)mPhaseError);
}
//Decode the dibit from the symbol and send to the listener
if(mDibitListener != null)
{
mDibitListener.receive(mQPSKSymbolDecoder.decode(mCurrentSymbol));
}
//Send to an external constellation symbol listener when registered
if(mSymbolListener != null)
{
mSymbolListener.receive(mCurrentSymbol);
}
//TODO: Assemble dibits here and broadcast
}
}
/**
* Registers the listener to receive decoded QPSK symbols
*/
public void setSymbolListener(Listener<Complex> listener)
{
mSymbolListener = listener;
}
/**
* Registers the listener to receive decoded QPSK dibits
*/
public void setDibitListener(Listener<Dibit> listener)
{
mDibitListener = listener;
}
/**
* Registers the listener to receive PLL error values
*/
public void setPLLErrorListener(Listener<Double> listener)
{
mPLLErrorListener = listener;
}
}

40
src/main/java/io/github/dsheirer/dsp/psk/QPSKPolarSlicer.java → src/main/java/io/github/dsheirer/dsp/psk/QPSKSymbolDecoder.java
View File

@@ -1,3 +1,18 @@
/*******************************************************************************
* sdr-trunk
* Copyright (C) 2014-2018 Dennis Sheirer
*
* 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, either version 3 of the License, or (at your option) any
* later version.
*
* 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 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/>
*
******************************************************************************/
package io.github.dsheirer.dsp.psk;
import io.github.dsheirer.dsp.symbol.Dibit;
@@ -5,24 +20,7 @@ import io.github.dsheirer.sample.Broadcaster;
import io.github.dsheirer.sample.Listener;
import io.github.dsheirer.sample.complex.Complex;
/*******************************************************************************
* SDR Trunk
* Copyright (C) 2014,2015 Dennis Sheirer
*
* 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, either version 3 of the License, or
* (at your option) any later version.
*
* 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 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/>
******************************************************************************/
public class QPSKPolarSlicer implements Listener<Complex>
public class QPSKSymbolDecoder implements Listener<Complex>, IQPSKSymbolDecoder
{
private Broadcaster<Dibit> mBroadcaster = new Broadcaster<Dibit>();
@@ -37,7 +35,7 @@ public class QPSKPolarSlicer implements Listener<Complex>
* / \
* / 11 \
*/
public QPSKPolarSlicer()
public QPSKSymbolDecoder()
{
}
@@ -60,10 +58,10 @@ public class QPSKPolarSlicer implements Listener<Complex>
@Override
public void receive( Complex complex )
{
mBroadcaster.broadcast( decide( complex ) );
mBroadcaster.broadcast( decode( complex ) );
}
public static Dibit decide( Complex complex )
public Dibit decode(Complex complex )
{
if( Math.abs( complex.inphase() ) > Math.abs( complex.quadrature() ) )
{

63
src/main/java/io/github/dsheirer/dsp/psk/QPSKSymbolPhaseErrorCalculator.java Normal file
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@@ -0,0 +1,63 @@
/*******************************************************************************
* sdr-trunk
* Copyright (C) 2014-2018 Dennis Sheirer
*
* 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, either version 3 of the License, or (at your option) any
* later version.
*
* 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 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/>
*
******************************************************************************/
package io.github.dsheirer.dsp.psk;
import io.github.dsheirer.sample.complex.Complex;
/**
* Calculates the phase error for a QPSK polar-orientation constellation
*/
public class QPSKSymbolPhaseErrorCalculator implements ISymbolPhaseErrorCalculator
{
private float mPhaseError;
@Override
public void adjust(Complex symbol)
{
//No-op - since there is no differential, we don't have to adjust
}
@Override
public float getPhaseError(Complex symbol)
{
mPhaseError = 0.0f;
if(Math.abs(symbol.inphase()) > Math.abs(symbol.quadrature()))
{
if(symbol.inphase() > 0)
{
mPhaseError = -symbol.quadrature();
}
else
{
mPhaseError = symbol.quadrature();
}
}
else
{
if(symbol.quadrature() > 0)
{
mPhaseError = symbol.inphase();
}
else
{
mPhaseError = -symbol.inphase();
}
}
return mPhaseError;
}
}

35
src/main/java/io/github/dsheirer/dsp/psk/SymbolInversion.java Normal file
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@@ -0,0 +1,35 @@
/*******************************************************************************
* sdr-trunk
* Copyright (C) 2014-2018 Dennis Sheirer
*
* 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, either version 3 of the License, or (at your option) any
* later version.
*
* 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 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/>
*
******************************************************************************/
package io.github.dsheirer.dsp.psk;
public enum SymbolInversion
{
DEGREES_90_PLUS(Math.PI / 2.0),
DEGREES_90_MINUS(Math.PI / -2.0),
DEGREES_180(Math.PI);
private double mAngleRadians;
SymbolInversion(double angleRadians)
{
mAngleRadians = angleRadians;
}
public double getError()
{
return mAngleRadians;
}
}

337
src/main/java/io/github/dsheirer/dsp/psk/pll/CostasLoop.java Normal file
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@@ -0,0 +1,337 @@
/*******************************************************************************
* sdr-trunk
* Copyright (C) 2014-2018 Dennis Sheirer
*
* 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, either version 3 of the License, or (at your option) any
* later version.
*
* 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 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/>
*
******************************************************************************/
package io.github.dsheirer.dsp.psk.pll;
import io.github.dsheirer.buffer.DoubleCircularBuffer;
import io.github.dsheirer.dsp.mixer.Oscillator;
import io.github.dsheirer.sample.complex.Complex;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.text.DecimalFormat;
/**
* Costas Loop - phase locked loop designed to automatically synchronize to the incoming carrier frequency in order to
* zeroize any frequency offset inherent in the signal due to either mis-tuning or carrier frequency drift.
*
* Costas loop structure was modeled from KA1RBI's OP25/cqpsk.py
*
* Loop bandwidth and alpha/beta gain formulas derived from:
* http://www.trondeau.com/blog/2011/8/13/control-loop-gain-values.html
*/
public class CostasLoop implements IPhaseLockedLoop
{
private final static Logger mLog = LoggerFactory.getLogger(CostasLoop.class);
public static final double TWO_PI = 2.0 * Math.PI;
private DoubleCircularBuffer mErrorBuffer = new DoubleCircularBuffer(10);
private double mDamping = Math.sqrt(2.0) / 2.0;
private double mAlphaGain;
private double mBetaGain;
private double mLoopPhase = 0.0;
private double mLoopFrequency = 0.0;
private double mMaximumLoopFrequency;
private Complex mCurrentVector = new Complex(0, 0);
private Tracking mTracking = Tracking.SEARCHING;
private ITrackingStateListener mTrackingStateListener;
private boolean mAutomaticTrackingEnabled = true;
/**
* Costas Loop for tracking and correcting frequency error in a received carrier signal.
*
* @param sampleRate of the incoming samples
* @param symbolRate of the digital signal
*/
public CostasLoop(double sampleRate, double symbolRate)
{
mMaximumLoopFrequency = TWO_PI * (symbolRate / 2.0) / sampleRate;
updateLoopBandwidth();
}
/**
* Corrects the current phase tracker when an inverted output is detected. The inversion will take the form of
* +/- 90 degrees or +/- 180 degrees, although the latter correction is equal regardless of the sign.
*
* If the supplied correction value places the loop frequency outside of the max frequency, then the frequency will
* be corrected 360 degrees in the opposite direction to maintain within the max frequency bounds.
*
* @param correction as measured in radians
*/
public void correctInversion(double correction)
{
mLoopFrequency += correction;
if(mLoopFrequency > mMaximumLoopFrequency)
{
mLoopFrequency -= 2.0 * mMaximumLoopFrequency;
}
if(mLoopFrequency < -mMaximumLoopFrequency)
{
mLoopFrequency += 2.0 * mMaximumLoopFrequency;
}
}
/**
* Updates the loop bandwidth and alpha/beta gains according to the current loop synchronization state.
*/
private void updateLoopBandwidth()
{
double bandwidth = TWO_PI / mTracking.getLoopBandwidth();
mAlphaGain = (4.0 * mDamping * bandwidth) / (1.0 + (2.0 * mDamping * bandwidth) + (bandwidth * bandwidth));
mBetaGain = (4.0 * bandwidth * bandwidth) / (1.0 + (2.0 * mDamping * bandwidth) + (bandwidth * bandwidth));
}
/**
* Sets the tracking state for this costas loop. The tracking state affects the aggressiveness of the alpha/beta
* gain values in synchronizing with the signal carrier.
*
* @param tracking
*/
public void setTracking(Tracking tracking)
{
mTracking = tracking;
updateLoopBandwidth();
mLog.debug("Tracking: " + tracking.name());
if(mTrackingStateListener != null)
{
mTrackingStateListener.trackingStateChanged(tracking);
}
}
/**
* Sets the listener to receive notifications when the tracking state changes
*/
public void setTrackingStateListener(ITrackingStateListener listener)
{
mTrackingStateListener = listener;
}
/**
* Enables or disables automatic tracking state updates. When enabled, the loop will automatically increase or
* decrease the loop alpha/beta gain values based on the variance of the error tracking values submitted to the
* loop control. As the variance decreases, so will the gain values, and vice-versa. Setting this to disabled
* will force the tracker to retain the gain values associated with either the default or user-specified tracking
* value.
*
* @param enabled true (default) to enable automatic gain tracking
*/
public void setAutomaticTracking(boolean enabled)
{
mAutomaticTrackingEnabled = enabled;
}
/**
* Increments the phase of the loop for each sample received at the sample rate.
*/
public void increment()
{
mLoopPhase += mLoopFrequency;
/* Keep the loop phase in bounds */
normalizePhase();
}
/**
* Current vector of the loop. Note: this value is updated for the current angle in radians each time this method
* is invoked.
*/
public Complex getCurrentVector()
{
mCurrentVector.setAngle(mLoopPhase);
return mCurrentVector;
}
@Override
public Complex incrementAndGetCurrentVector()
{
increment();
return getCurrentVector();
}
public double getLoopFrequency()
{
return mLoopFrequency;
}
public double getMaximumLoopFrequency()
{
return mMaximumLoopFrequency;
}
/**
* Updates the costas loop frequency and phase to adjust for the phase
* error value
*
* @param phaseError - (-)= late and (+)= early
*/
public void adjust(double phaseError)
{
mLoopFrequency += (mBetaGain * phaseError);
mLoopPhase += mLoopFrequency + (mAlphaGain * phaseError);
/* Maintain phase between +/- 2 * PI */
normalizePhase();
/* Limit frequency to +/- maximum loop frequency */
limitFrequency();
mErrorBuffer.put(phaseError);
double variance = mErrorBuffer.variance();
switch(mTracking)
{
case SEARCHING:
if(Tracking.COARSE.meetsThreshold(variance))
{
setTracking(Tracking.COARSE);
}
break;
case COARSE:
if(Tracking.COARSE.meetsThreshold(variance))
{
if(Tracking.FINE.meetsThreshold(variance))
{
setTracking(Tracking.FINE);
}
}
else
{
setTracking(Tracking.SEARCHING);
}
break;
case FINE:
if(Tracking.FINE.meetsThreshold(variance))
{
if(Tracking.LOCKED.meetsThreshold(variance))
{
setTracking(Tracking.LOCKED);
}
}
else
{
setTracking(Tracking.COARSE);
}
break;
case LOCKED:
if(!Tracking.LOCKED.meetsThreshold(variance))
{
setTracking(Tracking.FINE);
}
break;
}
}
public double getErrorMean()
{
return mErrorBuffer.mean();
}
public double getErrorVariance()
{
return mErrorBuffer.variance();
}
/**
* Normalizes the phase tracker to maintain within +/- 2 Pi
*/
private void normalizePhase()
{
while(mLoopPhase > TWO_PI)
{
mLoopPhase -= TWO_PI;
}
while(mLoopPhase < -TWO_PI)
{
mLoopPhase += TWO_PI;
}
}
/**
* Constrains the frequency within the bounds of +/- loop frequency
*/
private void limitFrequency()
{
if(mLoopFrequency > mMaximumLoopFrequency)
{
mLoopFrequency = mMaximumLoopFrequency;
}
if(mLoopFrequency < -mMaximumLoopFrequency)
{
mLoopFrequency = -mMaximumLoopFrequency;
}
}
/**
* Tracking state listener interface for receiving updates when the tracking state of the costas loop changes
*/
public interface ITrackingStateListener
{
void trackingStateChanged(Tracking tracking);
}
public static void main(String[] arguments)
{
DecimalFormat decimalFormat = new DecimalFormat("0.000000");
double sampleRate = 25000.0;
int errorFrequency = 411;
double loopBandwidth = 50.0;
Oscillator oscillator = new Oscillator(errorFrequency, (int)sampleRate);
CostasLoop costasLoop = new CostasLoop(sampleRate, 4800.0);
costasLoop.setTrackingStateListener(new ITrackingStateListener()
{
@Override
public void trackingStateChanged(Tracking tracking)
{
mLog.debug("Tracking State Changed: " + tracking.name());
}
});
for(int x = 0; x < 1000; x++)
{
Complex complex = oscillator.getComplex();
oscillator.rotate();
costasLoop.increment();
if(x % 5 == 0)
{
complex.multiply(costasLoop.getCurrentVector().conjugate());
double phaseError = complex.angle();
costasLoop.adjust(phaseError);
double loopFrequency = costasLoop.getLoopFrequency() * sampleRate / TWO_PI;
double maxFrequency = costasLoop.getMaximumLoopFrequency() * sampleRate / TWO_PI;
mLog.debug(x + " Frequency: " + errorFrequency +
" Loop:" + decimalFormat.format(loopFrequency) +
" Max:" + maxFrequency +
" Detected Error:" + decimalFormat.format(phaseError) +
" Avg:" + decimalFormat.format(costasLoop.getErrorMean()) +
" Var:" + decimalFormat.format(costasLoop.getErrorVariance()));
}
}
}
}

56
src/main/java/io/github/dsheirer/dsp/psk/pll/IPhaseLockedLoop.java Normal file
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@@ -0,0 +1,56 @@
/*******************************************************************************
* sdr-trunk
* Copyright (C) 2014-2018 Dennis Sheirer
*
* 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, either version 3 of the License, or (at your option) any
* later version.
*
* 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 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/>
*
******************************************************************************/
package io.github.dsheirer.dsp.psk.pll;
import io.github.dsheirer.sample.complex.Complex;
/**
* Phase-Locked Loop (PLL) interface
*/
public interface IPhaseLockedLoop
{
/**
* Increments the PLL by one sample period
*/
void increment();
/**
* Applies an error value to the PLL.
*
* @param error value in the range of -PI <> +PI
*/
void adjust(double error);
/**
* Adjusts the current phase of the loop to account for +/-90 or 180 degree inverted phase locks when detected
* @param correction to apply to the phase of the loop
*/
void correctInversion(double correction);
/**
* Current vector of the PLL to use in de-spinning the incoming samples.
* @return complex vector
*/
Complex getCurrentVector();
/**
* Increments the phase rotation and gets the current vector of the PLL to use in de-spinning the incoming samples.
* @return complex vector
*/
Complex incrementAndGetCurrentVector();
}

48
src/main/java/io/github/dsheirer/dsp/psk/pll/Tracking.java Normal file
View File

@@ -0,0 +1,48 @@
/*******************************************************************************
* sdr-trunk
* Copyright (C) 2014-2018 Dennis Sheirer
*
* 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, either version 3 of the License, or (at your option) any
* later version.
*
* 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 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/>
*
******************************************************************************/
package io.github.dsheirer.dsp.psk.pll;
public enum Tracking
{
SEARCHING(50.0, Math.PI),
COARSE(100.0, 0.01),
FINE(150.0, 0.001),
LOCKED(200.0, 0.0001);
private double mLoopBandwidth;
private double mVarianceThreshold;
Tracking(double loopBandwidth, double varianceThreshold)
{
mLoopBandwidth = loopBandwidth;
mVarianceThreshold = varianceThreshold;
}
public double getLoopBandwidth()
{
return mLoopBandwidth;
}
public double getVarianceThreshold()
{
return mVarianceThreshold;
}
public boolean meetsThreshold(double variance)
{
return variance < getVarianceThreshold();
}
}