Updated spectral display to used dBm scale and removed baseline/amplification items.

Updated sample handling code to use -1.0 to 1.0 float values throughout, to support P25 decoder and symbol filter.

src/instrument/gui/WaveSourceFrame.java

@@ -156,7 +156,7 @@ public class WaveSourceFrame extends JInternalFrame implements PositionListener
 						case PASSPORT:
 							decoder = new PassportDecoder( SampleType.REAL, null );
 							break;
-						case P25:
+						case P25_PHASE1:
 							decoder = new P25Decoder( SampleType.REAL, null );
 							break;
 					}