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AM Decoder final commit. Includes automatic gain control on baseband input and audio output.

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dennis.sheirer
2014-10-31 16:58:09 +00:00
parent d34abdd2fa
commit 5e7c8a8a57
3 changed files with 239 additions and 47 deletions
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37
src/decode/am/AMDecoder.java
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@@ -1,10 +1,13 @@
package decode.am;
import sample.simplex.SimplexSampleListener;
import sample.real.RealSampleListener;
import source.Source.SampleType;
import decode.Decoder;
import decode.DecoderType;
import dsp.agc.ComplexAutomaticGainControl;
import dsp.agc.RealAutomaticGainControl;
import dsp.am.AMDemodulator;
import dsp.filter.ComplexFIRFilter;
import dsp.filter.DCRemovalFilter2;
import dsp.filter.FilterFactory;
import dsp.filter.FloatFIRFilter;
@@ -18,8 +21,14 @@ public class AMDecoder extends Decoder
*/
private static final double DC_REMOVAL_RATIO = 0.003;
private AMDemodulator mDemodulator;
private DCRemovalFilter2 mDCRemovalFilter;
private ComplexFIRFilter mIQFilter;
private ComplexAutomaticGainControl mBasebandAGC =
new ComplexAutomaticGainControl();
private AMDemodulator mDemodulator = new AMDemodulator();
private DCRemovalFilter2 mDCRemovalFilter =
new DCRemovalFilter2( DC_REMOVAL_RATIO );
private RealAutomaticGainControl mAudioAGC = new RealAutomaticGainControl();
private FloatFIRFilter mLowPassFilter;
public AMDecoder( SampleType sampleType )
@@ -33,6 +42,9 @@ public class AMDecoder extends Decoder
*/
if( mSourceSampleType == SampleType.COMPLEX )
{
mIQFilter = new ComplexFIRFilter(
FilterFactory.getLowPass( 48000, 6500, 73, WindowType.HAMMING ),
1.0 );
/**
* The Decoder super class is both a Complex listener and a float
* listener. So, we add the demod to listen to the incoming
@@ -40,15 +52,15 @@ public class AMDecoder extends Decoder
* back to this class, so we can receive the demodulated output
* to process
*/
mDemodulator = new AMDemodulator();
this.addComplexListener( mIQFilter );
mIQFilter.setListener( mBasebandAGC );
mBasebandAGC.setListener( mDemodulator );
this.addComplexListener( mDemodulator );
/**
* Remove the DC component that is present when we're mistuned
*/
mDCRemovalFilter = new DCRemovalFilter2( DC_REMOVAL_RATIO );
mDemodulator.addListener( mDCRemovalFilter );
mDemodulator.setListener( mDCRemovalFilter );
/**
* Route the demodulated, filtered samples back to this class to send
@@ -56,12 +68,12 @@ public class AMDecoder extends Decoder
*/
mLowPassFilter = new FloatFIRFilter(
FilterFactory.getLowPass( 48000, 3000, 31,
WindowType.COSINE ), 100.0 );
FilterFactory.getLowPass( 48000, 3000, 31, WindowType.COSINE ), 1.0 );
mDCRemovalFilter.setListener( mLowPassFilter );
mLowPassFilter.setListener( this.getSimplexReceiver() );
mLowPassFilter.setListener( mAudioAGC );
mAudioAGC.setListener( this.getRealReceiver() );
}
}
@@ -72,8 +84,9 @@ public class AMDecoder extends Decoder
}
@Override
public void addUnfilteredSimplexSampleListener( SimplexSampleListener listener )
public void addUnfilteredRealSampleListener( RealSampleListener listener )
{
mDemodulator.addListener( listener );
throw new IllegalArgumentException( "cannot add real sample "
+ "listener to AM demodulator - not implemented" );
}
}