#1067 P25 Phase 1 C4FM/LSM decoder redesign. (#2294)

C4FM now uses SIMD differential decoding and soft sync detection.
LSM updated with soft sync detector and retains original Gardner error detector.
Adds new QPSK symbol view in the now playing channel tab.
Restores PLL error driven tuner Auto-PPM feature.
Deletes the demod viewer GUI application and all instrumented decoders
Updates DMR to send soft symbols to new symbol view in Now Playing.

Co-authored-by: Dennis Sheirer <dsheirer@github.com>

src/main/java/io/github/dsheirer/gui/symbol/ChannelView.java

@@ -0,0 +1,55 @@
+/*
+ * *****************************************************************************
+ * Copyright (C) 2014-2025 Dennis Sheirer
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ * ****************************************************************************
+ */
+
+package io.github.dsheirer.gui.symbol;
+
+import javafx.scene.layout.VBox;
+
+/**
+ * Base class for channel viewer panel
+ */
+public class ChannelView extends VBox
+{
+    private boolean mShowing = false;
+
+    /**
+     * Constructs an instance.
+     */
+    public ChannelView()
+    {
+    }
+
+    /**
+     * Indicates if this panel is currently showing.
+      * @return true if showing.
+     */
+    protected boolean isShowing()
+    {
+        return mShowing;
+    }
+
+    /**
+     * Toggle the showing state to indicate when the user has selected to show this panel.
+     * @param showing true or false to disable the panel.
+     */
+    public void setShowing(boolean showing)
+    {
+        mShowing = showing;
+    }
+}

src/main/java/io/github/dsheirer/gui/symbol/SymbolView.java

@@ -0,0 +1,133 @@
+/*
+ * *****************************************************************************
+ * Copyright (C) 2014-2025 Dennis Sheirer
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ * ****************************************************************************
+ */
+
+package io.github.dsheirer.gui.symbol;
+
+import io.github.dsheirer.module.decode.FeedbackDecoder;
+import io.github.dsheirer.sample.Listener;
+import java.util.Arrays;
+import javafx.application.Platform;
+import javafx.scene.chart.NumberAxis;
+import javafx.scene.chart.ScatterChart;
+import javafx.scene.chart.XYChart;
+import javafx.scene.layout.Priority;
+import javafx.scene.layout.VBox;
+
+/**
+ * Chart display for received QPSK symbols
+ */
+public class SymbolView extends ChannelView implements Listener<Float>
+{
+    private static final int SYMBOL_DISPLAY_COUNT = 4800;
+    private static final int SYMBOL_QUEUE_SIZE = SYMBOL_DISPLAY_COUNT / 40;
+    private final float[] mSymbolQueue = new float[SYMBOL_QUEUE_SIZE];
+    private int mSymbolQueuePointer = 0;
+    private int mChartSymbolPointer = 0;
+    private final NumberAxis mSymbolTiming = new NumberAxis();
+    private final NumberAxis mSymbolPhase = new NumberAxis(-Math.PI, Math.PI, Math.PI / 2);
+    private final XYChart.Series<Number, Number> mSymbolSeries = new XYChart.Series<>();
+    private final ScatterChart<Number, Number> mSymbolChart = new ScatterChart<>(mSymbolTiming, mSymbolPhase);
+    private FeedbackDecoder mFeedbackDecoder;
+
+    /**
+     * Constructs an instance
+     */
+    public SymbolView()
+    {
+        mSymbolSeries.setName("xx Demodulated Symbols");
+
+        for(int x = 0; x < SYMBOL_DISPLAY_COUNT; x++)
+        {
+            mSymbolSeries.getData().add(new XYChart.Data<>(x, 0));
+        }
+
+        mSymbolChart.getData().add(mSymbolSeries);
+        mSymbolChart.setMaxHeight(Double.MAX_VALUE);
+        mSymbolChart.setMaxWidth(Double.MAX_VALUE);
+        mSymbolChart.setAnimated(false);
+        VBox.setVgrow(mSymbolChart, Priority.ALWAYS);
+        getChildren().add(mSymbolChart);
+    }
+
+    /**
+     * Updates the chart axis label with the currently displayed protocol
+     * @param protocol that is being processed/displayed.
+     */
+    public void setProtocol(String protocol)
+    {
+        Platform.runLater(() -> mSymbolSeries.setName(protocol + " Demodulated Symbols"));
+    }
+
+    /**
+     * Registers the decoder with this view and this view then registers as a symbol listener on the decoder.
+     * @param feedbackDecoder for this view
+     */
+    public void setSymbolProvider(FeedbackDecoder feedbackDecoder)
+    {
+        removeSymbolProvider();
+
+        mFeedbackDecoder = feedbackDecoder;
+
+        if(mFeedbackDecoder != null)
+        {
+            mFeedbackDecoder.setSymbolListener(this);
+        }
+    }
+
+    /**
+     * Removes current symbol provider and unregisters this view from that provider.
+     */
+    public void removeSymbolProvider()
+    {
+        if(mFeedbackDecoder != null)
+        {
+            mFeedbackDecoder.removeSymbolListener();
+        }
+
+        mFeedbackDecoder = null;
+    }
+
+    @Override
+    public void receive(Float symbol)
+    {
+        if(isShowing())
+        {
+            mSymbolQueue[mSymbolQueuePointer++] = symbol;
+
+            //Flush the queued symbols to the chart when the queue is full
+            if(mSymbolQueuePointer == SYMBOL_QUEUE_SIZE)
+            {
+                float[] symbolDataCopy = Arrays.copyOf(mSymbolQueue, mSymbolQueue.length);
+
+                //Execute the chart data update on the JavaFX UI thread
+                Platform.runLater(() ->
+                {
+                    for(float v : symbolDataCopy)
+                    {
+                        mSymbolSeries.getData().get(mChartSymbolPointer++).setYValue(v);
+                        mChartSymbolPointer %= SYMBOL_DISPLAY_COUNT;
+                    }
+
+                });
+
+                mSymbolQueuePointer = 0;
+            }
+        }
+    }
+}