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330 WIP - implements the new data-directed symbol timing and phase

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error calculator.  After increasing the gain for symbol timing, this
new symbol evaluator class seems to track the signal very accurately
despite lots of noise and ISI.
This commit is contained in:
Denny
2018-03-04 11:42:23 -05:00
parent b563f2d11b
commit 45a6c5a0b6
9 changed files with 58 additions and 76 deletions
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10
src/main/java/io/github/dsheirer/module/decode/p25/P25_C4FMDecoder2.java
View File

@@ -21,12 +21,8 @@ import io.github.dsheirer.dsp.filter.design.FilterDesignException;
import io.github.dsheirer.dsp.filter.fir.FIRFilterSpecification;
import io.github.dsheirer.dsp.filter.fir.complex.ComplexFIRFilter;
import io.github.dsheirer.dsp.psk.DQPSKDemodulator;
import io.github.dsheirer.dsp.psk.DQPSKSymbolPhaseErrorCalculator;
import io.github.dsheirer.dsp.psk.IQPSKSymbolDecoder;
import io.github.dsheirer.dsp.psk.ISymbolPhaseErrorCalculator;
import io.github.dsheirer.dsp.psk.InterpolatingSampleBuffer;
import io.github.dsheirer.dsp.psk.InterpolatingSampleBufferInstrumented;
import io.github.dsheirer.dsp.psk.QPSKStarSlicer;
import io.github.dsheirer.dsp.psk.pll.CostasLoop;
import io.github.dsheirer.sample.Listener;
import io.github.dsheirer.sample.complex.ComplexBuffer;
@@ -43,8 +39,6 @@ public class P25_C4FMDecoder2 extends P25Decoder implements IComplexBufferListen
{
private final static Logger mLog = LoggerFactory.getLogger(P25_C4FMDecoder2.class);
protected static final double SYMBOL_RATE = 4800;
protected ISymbolPhaseErrorCalculator mSymbolPhaseErrorCalculator = new DQPSKSymbolPhaseErrorCalculator();
protected IQPSKSymbolDecoder mSymbolDecoder = new QPSKStarSlicer();
protected InterpolatingSampleBuffer mInterpolatingSampleBuffer;
protected DQPSKDemodulator mQPSKDemodulator;
protected CostasLoop mCostasLoop;
@@ -72,8 +66,7 @@ public class P25_C4FMDecoder2 extends P25Decoder implements IComplexBufferListen
mCostasLoop = new CostasLoop(mSampleRate, SYMBOL_RATE);
mInterpolatingSampleBuffer = new InterpolatingSampleBufferInstrumented((float)(sampleRate / SYMBOL_RATE));
mQPSKDemodulator = new DQPSKDemodulator(mCostasLoop, mSymbolPhaseErrorCalculator, mSymbolDecoder,
mInterpolatingSampleBuffer);
mQPSKDemodulator = new DQPSKDemodulator(mCostasLoop, mInterpolatingSampleBuffer);
//Message framer can trigger a symbol-inversion correction to the PLL when detected
mMessageFramer = new P25MessageFramer(getAliasList(), mCostasLoop);
@@ -91,6 +84,7 @@ public class P25_C4FMDecoder2 extends P25Decoder implements IComplexBufferListen
protected ComplexBuffer filter(ComplexBuffer complexBuffer)
{
return mBasebandFilter.filter(complexBuffer);
// return complexBuffer;
}
private double getSampleRate()

3
src/main/java/io/github/dsheirer/module/decode/p25/P25_C4FMDecoder2Instrumented.java
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@@ -61,8 +61,7 @@ public class P25_C4FMDecoder2Instrumented extends P25_C4FMDecoder2
InterpolatingSampleBufferInstrumented instrumentedBuffer = new InterpolatingSampleBufferInstrumented((float)(sampleRate / SYMBOL_RATE));
mInterpolatingSampleBuffer = instrumentedBuffer;
DQPSKDemodulatorInstrumented instrumented = new DQPSKDemodulatorInstrumented(mCostasLoop,
mSymbolPhaseErrorCalculator, mSymbolDecoder, instrumentedBuffer, mSampleRate);
DQPSKDemodulatorInstrumented instrumented = new DQPSKDemodulatorInstrumented(mCostasLoop, instrumentedBuffer, mSampleRate);
mQPSKDemodulator = instrumented;
instrumented.setSymbolListener(mSymbolListener);