Adds an AM Demodulator to the list of available decoders.

src/dsp/am/AMDemodulator.java

@@ -0,0 +1,62 @@
+package dsp.am;
+
+import sample.Broadcaster;
+import sample.Listener;
+import sample.complex.ComplexSample;
+import dsp.filter.ComplexFIRFilter;
+import dsp.filter.FilterFactory;
+import dsp.filter.Window.WindowType;
+
+public class AMDemodulator implements Listener<ComplexSample>
+{
+    private Broadcaster<Float> mBroadcaster = new Broadcaster<Float>();
+    private ComplexFIRFilter mIQFilter;
+
+    public AMDemodulator()
+    {
+        this( FilterFactory.getLowPass( 48000, 2000, 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 );
+    }
+
+    /**
+     * Adds a listener to receive demodulated samples
+     */
+    public void addListener( Listener<Float> listener )
+    {
+        mBroadcaster.addListener( listener );
+    }
+
+    /**
+     * Removes a listener from receiving demodulated samples
+     */
+    public void removeListener( Listener<Float> 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 );
+        }
+    }
+}