#2494 P25P1 and NXDN Decoder Enhancements. (#2514)

- Updates P25P1 C4FM decoder to use same pattern developed for NXDN.
- Both share the C4FM symbol processor and equalizer.
- P25P1 updated with Garner style timing error detector
- NXDN filters updated to use a combined RRC and inverse sync filter all in one.
- P25P1 replaces RRC with band limiting filter
- P25P1 enhanced with dynamic PLL balance updates to combat multi-path fading, in addition to the sync detection training window.
- Decoder PPM error reports now only sent after 2x consecutive sync detections to prevent tuner PPM corrections from noisy/isolated false sync detects.
- Soft error correction added to both P25P1 and IDEN.

Co-authored-by: denny <dennis.sheirer@gmail.com>

src/main/java/io/github/dsheirer/source/config/SourceConfigTunerMultipleFrequency.java

@@ -39,7 +39,7 @@ public class SourceConfigTunerMultipleFrequency extends SourceConfiguration
     private List<Long> mFrequencies = new ArrayList<>();
     private String mPreferredTuner;
     private Long mPreferredFrequency;
-    private int mFrequencyRotationDelay = ChannelRotationMonitor.CHANNEL_ROTATION_DELAY_MINIMUM;
+    private int mFrequencyRotationDelay = ChannelRotationMonitor.CHANNEL_ROTATION_DELAY_DEFAULT;
 
     public SourceConfigTunerMultipleFrequency()
     {

src/main/java/io/github/dsheirer/source/tuner/channel/rotation/ChannelRotationMonitor.java

@@ -45,7 +45,7 @@ public class ChannelRotationMonitor extends Module implements ISourceEventProvid
         Listener<DecoderStateEvent>
 {
     public static final int CHANNEL_ROTATION_DELAY_MINIMUM = 200;
-    public static final int CHANNEL_ROTATION_DELAY_DEFAULT = 500;
+    public static final int CHANNEL_ROTATION_DELAY_DEFAULT = 1000;
     public static final int CHANNEL_ROTATION_DELAY_MAXIMUM = 2000;
 
     private final static Logger mLog = LoggerFactory.getLogger(ChannelRotationMonitor.class);

src/main/java/io/github/dsheirer/source/tuner/frequency/ChannelFrequencyErrorManager.java

@@ -36,8 +36,9 @@ import java.util.concurrent.TimeUnit;
 public class ChannelFrequencyErrorManager implements ISourceEventListener, Listener<SourceEvent>
 {
     private static final long MAXIMUM_CHANNEL_ERROR_CORRECTION_PER_INTERVAL = 10; //Hertz
-    private static final long TIMER_INTERVAL_MILLISECONDS = 500;
-    private final FloatAveragingBuffer mRequestedCorrectAveragingBuffer = new FloatAveragingBuffer(6, 2);
+    private static final long TIMER_INTERVAL_MILLISECONDS = 1000;
+    private static final float ERROR_PROCESSING_GAIN = 0.3f;
+    private final FloatAveragingBuffer mRequestedCorrectAveragingBuffer = new FloatAveragingBuffer(12, 2);
     private final TunerChannelSource mTunerChannelSource;
     private final TunerFrequencyErrorManager mParent;
     private ScheduledFuture<?> mScheduledFuture;
@@ -135,7 +136,7 @@ public class ChannelFrequencyErrorManager implements ISourceEventListener, Liste
 
             if(partialCorrection != 0)
             {
-                mAppliedFrequencyCorrection += partialCorrection;
+                mAppliedFrequencyCorrection += (long)(partialCorrection * ERROR_PROCESSING_GAIN);
                 mTunerChannelSource.setFrequencyCorrection(mAppliedFrequencyCorrection);
                 mRequestedCorrectAveragingBuffer.reset();
             }

src/main/java/io/github/dsheirer/source/wave/ComplexWaveSource.java

@@ -66,7 +66,7 @@ public class ComplexWaveSource extends Source implements IControllableFileSource
     {
         if(file == null || !file.exists() || !supports(file))
         {
-            throw new IOException("Empty or null file");
+            throw new IOException("Empty or null file: " + file);
         }
 
         if(!supports(file))