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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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52
src/dsp/am/AMDemodulator.java
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@@ -2,62 +2,44 @@ package dsp.am;
import sample.Listener;
import sample.complex.ComplexSample;
import sample.simplex.SimplexSampleBroadcaster;
import sample.simplex.SimplexSampleListener;
import dsp.filter.ComplexFIRFilter;
import dsp.filter.FilterFactory;
import dsp.filter.Window.WindowType;
import sample.real.RealSampleListener;
import sample.real.RealSampleProvider;
public class AMDemodulator implements Listener<ComplexSample>
public class AMDemodulator implements Listener<ComplexSample>, RealSampleProvider
{
private SimplexSampleBroadcaster mBroadcaster = new SimplexSampleBroadcaster();
private ComplexFIRFilter mIQFilter;
private RealSampleListener mListener;
public AMDemodulator()
{
this( FilterFactory.getLowPass( 48000, 3000, 73, WindowType.HAMMING ),
1000.0 );
}
public AMDemodulator( double[] iqFilter, double iqGain )
{
mIQFilter = new ComplexFIRFilter( iqFilter, iqGain );
mIQFilter.setListener( new Demodulator() );
}
@Override
public void receive( ComplexSample sample )
{
mIQFilter.receive( sample );
float demodulated = (float)Math.sqrt( ( sample.real() *
sample.real() ) +
( sample.imaginery() *
sample.imaginery() ) );
if( mListener != null )
{
mListener.receive( demodulated * 500.0f );
}
}
/**
* Adds a listener to receive demodulated samples
*/
public void addListener( SimplexSampleListener listener )
public void setListener( RealSampleListener listener )
{
mBroadcaster.addListener( listener );
mListener = listener;
}
/**
* Removes a listener from receiving demodulated samples
*/
public void removeListener( SimplexSampleListener listener )
public void removeListener( RealSampleListener listener )
{
mBroadcaster.removeListener( listener );
}
public class Demodulator implements Listener<ComplexSample>
{
@Override
public void receive( ComplexSample sample )
{
float demodulated = (float)Math.abs(
Math.sqrt( ( sample.real() * sample.real() ) +
( sample.imaginery() * sample.imaginery() ) ) );
mBroadcaster.broadcast( demodulated * 30.0f );
}
mListener = null;
}
}