P25 LSM decoder work in progress. Adds a CQPSK decoder based on Max's (KA1RBI) scope.py and gardner loop.

The CQPSK decoder is starting to take shape, but needs more tweaking and testing.  It's not keeping a good lock on strong P25 signals.  I have to add some more features to the intrumentation package to allow me to visualize the internals of the CQPSK decoder so that I can get a better sense of what needs fine tuning.

The CQPSK decoder may work for anyone that wants to sync the repo and run the build script.

src/test/Interp.java

@@ -0,0 +1,57 @@
+package test;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import dsp.filter.interpolator.QPSKInterpolator;
+import sample.complex.ComplexSample;
+import util.Oscillator;
+
+public class Interp
+{
+	private final static Logger mLog = 
+			LoggerFactory.getLogger( Interp.class );
+
+	private Oscillator mNCO = new Oscillator( 1200, 48000 );
+	
+	public Interp()
+	{
+		
+	}
+	
+	public ComplexSample next()
+	{
+		return mNCO.nextComplex();
+	}
+	
+	public static void main( String[] args )
+	{
+		mLog.debug( "Starting" );
+
+		Interp interp = new Interp();
+		
+		ComplexSample[] samples = new ComplexSample[ 10 ];
+		
+		for( int x = 0; x < 10; x++ )
+		{
+			samples[ x ] = interp.next();
+		}
+		
+		QPSKInterpolator qi = new QPSKInterpolator();
+		
+		ComplexSample result = qi.filter( samples, 1, 0.25f );
+		
+
+		for( int x = 0; x < 10; x++ )
+		{
+			System.out.println( samples[x].toString() );
+//			mLog.debug( "Sample " + x + ": " + samples[ x ].toString() );
+		}
+		mLog.debug( "Result: " + result.toString() );
+		mLog.debug( "Finished" );
+	}
+
+}