#35 WIP new ObjectiveGainControl

DSheirer · Apr 30, 2023 · 4147f75 · 4147f75
1 parent ff4b7ef
commit 4147f75
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Showing 4 changed files with 146 additions and 26 deletions.
diff --git a/src/main/java/io/github/dsheirer/buffer/FloatCircularBuffer.java b/src/main/java/io/github/dsheirer/buffer/FloatCircularBuffer.java
@@ -129,7 +129,7 @@ public float max(float referenceValue)
             }
         }
 
-        System.out.println("Max [" + max + "] from " + Arrays.toString(mBuffer));
+//        System.out.println("Max [" + max + "] from " + Arrays.toString(mBuffer));
 
         return max;
     }

diff --git a/src/main/java/io/github/dsheirer/dsp/gain/AutomaticGainControl.java b/src/main/java/io/github/dsheirer/dsp/gain/AutomaticGainControl.java
@@ -20,10 +20,13 @@
 package io.github.dsheirer.dsp.gain;
 
 import io.github.dsheirer.buffer.FloatCircularBuffer;
+import io.github.dsheirer.source.wave.RealWaveSource;
 import org.apache.commons.math3.util.FastMath;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import java.io.File;
+
 /**
  * Audio automatic gain control.
  */
@@ -32,14 +35,12 @@ public class AutomaticGainControl
     private static final Logger mLog = LoggerFactory.getLogger(AutomaticGainControl.class);
     private static final float SAMPLE_RATE = 8000;
     /* Signal delay line - time delay in seconds */
-	private static final float DELAY_TIME_CONSTANT = 0.015f;
+    private static final float DELAY_TIME_CONSTANT = 0.015f;
     /* Peak detector window - time delay in seconds */
     private static final float WINDOW_TIME_CONSTANT = 0.018f;
     /* Attack time constants in seconds */
     private static final float ATTACK_RISE_TIME_CONSTANT = 0.002f;
     private static final float ATTACK_FALL_TIME_CONSTANT = 0.005f;
-//    private static final float ATTACK_RISE_TIME_CONSTANT = 0.2f;
-//    private static final float ATTACK_FALL_TIME_CONSTANT = 0.5f;
     private static final float ATTACK_RISE_ALPHA = 1.0f - (float)FastMath.exp(-1.0 / SAMPLE_RATE * ATTACK_RISE_TIME_CONSTANT);
     private static final float ATTACK_FALL_ALPHA = 1.0f - (float)FastMath.exp(-1.0 / SAMPLE_RATE * ATTACK_FALL_TIME_CONSTANT);
     /* AGC decay value in milliseconds (20 to 5000) */
@@ -48,26 +49,24 @@ public class AutomaticGainControl
     private static final float DECAY_RISEFALL_RATIO = 0.3f;
     private static final float DECAY_RISE_ALPHA = 1.0f - (float)FastMath.exp(-1.0 / (SAMPLE_RATE * DECAY * .001 * DECAY_RISEFALL_RATIO));
     private static final float DECAY_FALL_ALPHA = 1.f - (float)FastMath.exp(-1.0 / (SAMPLE_RATE * DECAY * .001));
-    /* Hang timer release decay time constant in seconds */
-    private static final float RELEASE_TIME_CONSTANT = 0.05f;
-    /* Specifies the AGC Knee in dB if AGC is active (nominal range -160 to 0 dB) */
-    private static final float THRESHOLD = -20.0f;
-    /* Limit output to about 3db of maximum */
-    private static final float AGC_OUT_SCALE = 0.7f;
     /* Keep max input and output the same */
-    private static final float MAX_AMPLITUDE = 32767.0f; //1.0;
-    private static final float MAX_MANUAL_AMPLITUDE = 32767.0f; //1.0;
+    private static final float MAX_AMPLITUDE = 1.0f; //1.0;
+    private static final float MAX_MANUAL_AMPLITUDE = 1.0f; //1.0;
     /* Specifies AGC manual gain in dB if AGC is not active ( 0 to 100 dB) */
-    private static final float MANUAL_GAIN = -90.308735f;
+    private static final float MANUAL_GAIN = 0.0f;
     private static final float MANUAL_AGC_GAIN = MAX_MANUAL_AMPLITUDE * (float)FastMath.pow(10.0, MANUAL_GAIN / 20.0);
+    /* Limit output to about 3db of maximum */
+    private static final float AGC_OUT_SCALE = 0.95f; //0.7f;
     /* Specifies dB reduction in output at knee from max output level (0 - 10dB) */
     private static final float SLOPE_FACTOR = 2.0f;
-    private static final float KNEE = THRESHOLD / 20.0f;
+    /* Specifies the threshold when the AGC kicks in (nominal range -160 to 0 dB) */
+    private static final float THRESHOLD = -20.0f; //-20.0f
+    private static final float KNEE = THRESHOLD / 20.0f; //20.0f
     private static final float GAIN_SLOPE = SLOPE_FACTOR / 100.0f;
     private static final float FIXED_GAIN = AGC_OUT_SCALE * (float)FastMath.pow(10.0, KNEE * (GAIN_SLOPE - 1.0));
     /* Constant for calc log() so that a value of 0 magnitude = -8 */
     private static final float MIN_CONSTANT = 3.2767E-4f;
-    private boolean mAGCEnabled = false;
+    private boolean mAGCEnabled = true;
     private float mPeakMagnitude = -5.0f;
     private float mAttackAverage = 0.0f;
     private float mDecayAverage = 0.0f;
@@ -81,16 +80,17 @@ public class AutomaticGainControl
      */
     public AutomaticGainControl()
     {
+        System.out.println("Fixed gain: " + FIXED_GAIN + " Knee: " + KNEE + " Gain Slope:" + GAIN_SLOPE);
         System.out.println("Manual gain: " + MANUAL_AGC_GAIN);
     }
 
     public void reset()
     {
         mLog.info("Previous - Min Gain: " + mMinGain + " Max Gain: " + mMaxGain);
         mLog.info("Resetting - Peak:" + mPeakMagnitude + " Attack:" + mAttackAverage + " Decay:" + mDecayAverage + " Mag Max:" + mMagnitudeBuffer.max(mPeakMagnitude));
-        mPeakMagnitude = -5.0f;
-        mAttackAverage = -5.0f;
-        mDecayAverage = -5.0f;
+        mPeakMagnitude = -8.0f;
+        mAttackAverage = -8.0f;
+        mDecayAverage = -8.0f;
         mDelayBuffer.reset(0.0f);
         mMagnitudeBuffer.reset(mPeakMagnitude);
     }
@@ -139,7 +139,7 @@ public float process(float currentSample)
             else if(delayedMagnitude == mPeakMagnitude)
             {
                 /* If delayed magnitude is the current peak, then find a new peak */
-                mPeakMagnitude = mMagnitudeBuffer.max(-5.0f);
+                mPeakMagnitude = mMagnitudeBuffer.max(-3.4845634f);
             }
 
             /* Exponential decay mode */
@@ -173,7 +173,9 @@ else if(delayedMagnitude == mPeakMagnitude)
                 gain = AGC_OUT_SCALE * (float)FastMath.pow(10.0, magnitude * (GAIN_SLOPE - 1.0));
             }
 
-//            mLog.info("Peak: " + mPeakMagnitude + " Attack: " + mAttackAverage + " Decay: " + mDecayAverage + " Gain: " + gain);
+            System.out.println("Current Mag: " + currentMagnitude + " Delay Mag: " + delayedMagnitude +
+                    " Peak:" + mPeakMagnitude + " Gain:" + gain +
+                    " Attack Avg:" + mAttackAverage + " Decay Avg:" + mDecayAverage);
         }
 
         if(gain < mMinGain)
@@ -206,10 +208,4 @@ public boolean isAGCEnabled()
         return mAGCEnabled;
     }
 
-    public static void main(String[] args)
-    {
-        AutomaticGainControl agc = new AutomaticGainControl();
-
-        System.out.println("Finished.");
-    }
 }
diff --git a/src/main/java/io/github/dsheirer/dsp/gain/ObjectiveGainControl.java b/src/main/java/io/github/dsheirer/dsp/gain/ObjectiveGainControl.java
@@ -0,0 +1,94 @@
+package io.github.dsheirer.dsp.gain;
+
+import org.apache.commons.math3.util.FastMath;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class ObjectiveGainControl
+{
+    private static final Logger mLog = LoggerFactory.getLogger(ObjectiveGainControl.class);
+    private float mMinGain;
+    private float mMaxGain;
+    private float mCurrentGain = 1.0f;
+    private float mObjectiveGain = mCurrentGain;
+    private float mObjectiveAmplitude;
+    private float mMaxObservedAmplitude;
+
+    public ObjectiveGainControl(float minGain, float maxGain, float objectiveAmplitude)
+    {
+        mMinGain = minGain;
+        mMaxGain = maxGain;
+        mObjectiveAmplitude = objectiveAmplitude;
+    }
+
+    public void reset()
+    {
+        mMaxObservedAmplitude = 0.0f;
+    }
+
+    public float[] process(float[] samples)
+    {
+        float currentAmplitude;
+
+        for(float sample: samples)
+        {
+            currentAmplitude = FastMath.abs(sample);
+
+            if(currentAmplitude > mMaxObservedAmplitude)
+            {
+                mMaxObservedAmplitude = currentAmplitude;
+            }
+        }
+
+        mObjectiveGain = mObjectiveAmplitude / mMaxObservedAmplitude;
+
+        if(mObjectiveGain > mMaxGain)
+        {
+            mObjectiveGain = mMaxGain;
+        }
+        else if(mObjectiveGain < mMinGain)
+        {
+            mObjectiveGain = mMinGain;
+        }
+
+        if(mCurrentGain != mObjectiveGain)
+        {
+            mLog.info("Current: " + mCurrentGain + " Objective: " + mObjectiveGain);
+            float incrementalGainChange = mObjectiveGain / samples.length / 4; //Aim to achieve objective over 4x sample buffers
+            float gain = mCurrentGain;
+
+            float[] processed = new float[samples.length];
+            for(int x = 0; x < samples.length; x++)
+            {
+                gain += incrementalGainChange;
+
+                if(gain > mMaxGain)
+                {
+                    gain = mMaxGain;
+                }
+                if(gain < mMinGain)
+                {
+                    gain = mMinGain;
+                }
+
+                processed[x] = samples[x] * gain;
+            }
+
+            if(Math.abs(mObjectiveGain - mCurrentGain) < incrementalGainChange)
+            {
+                mLog.info("Objective reached!");
+                mCurrentGain = mObjectiveGain;
+            }
+            else
+            {
+                mCurrentGain = gain;
+            }
+
+            return processed;
+        }
+        else
+        {
+            return samples;
+        }
+    }
+}
diff --git a/src/main/java/io/github/dsheirer/module/decode/am/AMDecoder.java b/src/main/java/io/github/dsheirer/module/decode/am/AMDecoder.java
@@ -21,8 +21,12 @@
 
 import io.github.dsheirer.dsp.am.SquelchingAMDemodulator;
 import io.github.dsheirer.dsp.gain.AutomaticGainControl;
+import io.github.dsheirer.dsp.gain.ObjectiveGainControl;
 import io.github.dsheirer.module.decode.DecoderType;
 import io.github.dsheirer.module.decode.analog.SquelchingAnalogDecoder;
+import io.github.dsheirer.source.wave.RealWaveSource;
+
+import java.io.File;
 
 /**
  * Decoder module with integrated squelching AM demodulator
@@ -69,4 +73,30 @@ protected void notifyCallStart()
         mAGC.reset();
         super.notifyCallStart();
     }
+
+    public static void main(String[] args)
+    {
+        ObjectiveGainControl agc = new ObjectiveGainControl(1.0f, 4.0f, 0.7f);
+
+        String path = "C:\\Users\\sheirerd\\SDRTrunk\\recordings\\20230430_052528Air_Boston_Center__TO_3.wav";
+        File file = new File(path);
+
+        try
+        {
+            RealWaveSource source = new RealWaveSource(file);
+            source.setListener(floats -> agc.process(floats));
+            source.open();
+
+            while(true)
+            {
+                source.next(256, true);
+            }
+
+        }
+        catch(Exception e)
+        {
+//            mLog.error("Error", e);
+        }
+        System.out.println("Finished.");
+    }
 }