mirror of
https://github.com/DSheirer/sdrtrunk.git
synced 2026-11-12 16:47:31 -05:00
#35 Updates AM & NBFM decoders to use Adaptive Squelch, a power squelch that includes an adaptive noise floor monitor. Implements vectorized magnitude operations for AM & FM decoders. Adds talkgroup assignment and squelch controls to AM channel configuration editor. Implements new AM gain control that attempts to normalize audio gain quickly at beginning of call/transmission and maintains that gain across lifecycle of the call and resets the gain for the next call. (#1540)
Notes on usage: - When using either AM or FM squelch control use either the Heterodyne channelizer or if using the Polyphase channelizer, avoid using trunk tracking decoders like DMR or P25 or set the squelch threshold high enough to avoid changes in noise floor from polyphase channelizer where it can vary between using the one channel or the two-channel combined channel sources. Co-authored-by: Dennis Sheirer <dsheirer@github.com>
This commit is contained in:
Denny Sheirer
@@ -1,6 +1,6 @@
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/*
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* *****************************************************************************
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* Copyright (C) 2014-2022 Dennis Sheirer
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* Copyright (C) 2014-2023 Dennis Sheirer
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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@@ -19,88 +19,80 @@
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package io.github.dsheirer.dsp.gain;
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import io.github.dsheirer.buffer.DoubleCircularBuffer;
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import io.github.dsheirer.buffer.RealCircularBuffer;
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import io.github.dsheirer.buffer.FloatCircularBuffer;
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import io.github.dsheirer.source.wave.RealWaveSource;
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import org.apache.commons.math3.util.FastMath;
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import org.slf4j.Logger;
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import org.slf4j.LoggerFactory;
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import java.io.File;
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/**
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* Audio automatic gain control.
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*/
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public class AutomaticGainControl
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{
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private static final double SAMPLE_RATE = 48000;
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private static final Logger mLog = LoggerFactory.getLogger(AutomaticGainControl.class);
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private static final float SAMPLE_RATE = 8000;
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/* Signal delay line - time delay in seconds */
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// private static final double DELAY_TIME_CONSTANT = 0.015;
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private static final double DELAY_TIME_CONSTANT = 0.01;
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private static final float DELAY_TIME_CONSTANT = 0.015f;
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/* Peak detector window - time delay in seconds */
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private static final double WINDOW_TIME_CONSTANT = 0.018;
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private static final float WINDOW_TIME_CONSTANT = 0.018f;
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/* Attack time constants in seconds */
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private static final double ATTACK_RISE_TIME_CONSTANT = 0.002;
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private static final double ATTACK_FALL_TIME_CONSTANT = 0.005;
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private static final double ATTACK_RISE_ALPHA = 1.0 -
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FastMath.exp(-1.0 / SAMPLE_RATE * ATTACK_RISE_TIME_CONSTANT);
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private static final double ATTACK_FALL_ALPHA = 1.0 -
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FastMath.exp(-1.0 / SAMPLE_RATE * ATTACK_FALL_TIME_CONSTANT);
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private static final float ATTACK_RISE_TIME_CONSTANT = 0.002f;
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private static final float ATTACK_FALL_TIME_CONSTANT = 0.005f;
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private static final float ATTACK_RISE_ALPHA = 1.0f - (float)FastMath.exp(-1.0 / SAMPLE_RATE * ATTACK_RISE_TIME_CONSTANT);
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private static final float ATTACK_FALL_ALPHA = 1.0f - (float)FastMath.exp(-1.0 / SAMPLE_RATE * ATTACK_FALL_TIME_CONSTANT);
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/* AGC decay value in milliseconds (20 to 5000) */
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private static final double DECAY = 200;
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/* Ratio between rise and fall times of decay time constants - adjust for
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* best action with SSB */
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private static final double DECAY_RISEFALL_RATIO = 0.3;
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private static final double DECAY_RISE_ALPHA = 1.0 -
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FastMath.exp(-1.0 / (SAMPLE_RATE * DECAY * .001 * DECAY_RISEFALL_RATIO));
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private static final double DECAY_FALL_ALPHA = 1.0 -
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FastMath.exp(-1.0 / (SAMPLE_RATE * DECAY * .001));
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/* Hang timer release decay time constant in seconds */
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@SuppressWarnings("unused")
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private static final double RELEASE_TIME_CONSTANT = 0.05;
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/* Specifies the AGC Knee in dB if AGC is active (nominal range -160 to 0 dB) */
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private static final double THRESHOLD = -100;
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/* Limit output to about 3db of maximum */
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private static final double AGC_OUT_SCALE = 0.7;
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private static final float DECAY = 200.0f;
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/* Ratio between rise and fall times of decay time constants - adjust for best action with SSB */
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private static final float DECAY_RISEFALL_RATIO = 0.3f;
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private static final float DECAY_RISE_ALPHA = 1.0f - (float)FastMath.exp(-1.0 / (SAMPLE_RATE * DECAY * .001 * DECAY_RISEFALL_RATIO));
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private static final float DECAY_FALL_ALPHA = 1.f - (float)FastMath.exp(-1.0 / (SAMPLE_RATE * DECAY * .001));
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/* Keep max input and output the same */
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private static final double MAX_AMPLITUDE = 32767.0; //1.0;
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private static final double MAX_MANUAL_AMPLITUDE = 32767.0; //1.0;
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private static final float MAX_AMPLITUDE = 1.0f; //1.0;
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private static final float MAX_MANUAL_AMPLITUDE = 1.0f; //1.0;
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/* Specifies AGC manual gain in dB if AGC is not active ( 0 to 100 dB) */
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private static final double MANUAL_GAIN = 0.0;
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private static final double MANUAL_AGC_GAIN = MAX_MANUAL_AMPLITUDE *
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FastMath.pow(10.0, MANUAL_GAIN / 20.0);
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private static final float MANUAL_GAIN = 0.0f;
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private static final float MANUAL_AGC_GAIN = MAX_MANUAL_AMPLITUDE * (float)FastMath.pow(10.0, MANUAL_GAIN / 20.0);
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/* Limit output to about 3db of maximum */
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private static final float AGC_OUT_SCALE = 0.95f; //0.7f;
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/* Specifies dB reduction in output at knee from max output level (0 - 10dB) */
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private static final double SLOPE_FACTOR = 2.0;
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private static final double KNEE = THRESHOLD / 20.0;
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private static final double GAIN_SLOPE = SLOPE_FACTOR / 100.0;
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private static final double FIXED_GAIN = AGC_OUT_SCALE *
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FastMath.pow(10.0, KNEE * (GAIN_SLOPE - 1.0));
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private static final float SLOPE_FACTOR = 2.0f;
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/* Specifies the threshold when the AGC kicks in (nominal range -160 to 0 dB) */
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private static final float THRESHOLD = -20.0f; //-20.0f
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private static final float KNEE = THRESHOLD / 20.0f; //20.0f
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private static final float GAIN_SLOPE = SLOPE_FACTOR / 100.0f;
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private static final float FIXED_GAIN = AGC_OUT_SCALE * (float)FastMath.pow(10.0, KNEE * (GAIN_SLOPE - 1.0));
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/* Constant for calc log() so that a value of 0 magnitude = -8 */
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private static final double MIN_CONSTANT = 3.2767E-4;
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private static final float MIN_CONSTANT = 3.2767E-4f;
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private boolean mAGCEnabled = true;
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private float mPeakMagnitude = -5.0f;
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private float mAttackAverage = 0.0f;
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private float mDecayAverage = 0.0f;
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private FloatCircularBuffer mDelayBuffer = new FloatCircularBuffer((int)(SAMPLE_RATE * DELAY_TIME_CONSTANT));
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private FloatCircularBuffer mMagnitudeBuffer = new FloatCircularBuffer((int)(SAMPLE_RATE * WINDOW_TIME_CONSTANT), mPeakMagnitude);
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private float mMaxGain = 0f;
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private float mMinGain = 100000f;
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private double mPeakMagnitude = 0.0;
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private double mAttackAverage = 0.0;
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private double mDecayAverage = 0.0;
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private RealCircularBuffer mDelayBuffer = new RealCircularBuffer((int)(SAMPLE_RATE * DELAY_TIME_CONSTANT));
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private DoubleCircularBuffer mMagnitudeBuffer = new DoubleCircularBuffer((int)(SAMPLE_RATE * WINDOW_TIME_CONSTANT));
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/**
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* Construct an instance
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*/
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public AutomaticGainControl()
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{
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System.out.println("Fixed gain: " + FIXED_GAIN + " Knee: " + KNEE + " Gain Slope:" + GAIN_SLOPE);
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System.out.println("Manual gain: " + MANUAL_AGC_GAIN);
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}
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public void reset()
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{
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mLog.info("Previous - Min Gain: " + mMinGain + " Max Gain: " + mMaxGain);
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mLog.info("Resetting - Peak:" + mPeakMagnitude + " Attack:" + mAttackAverage + " Decay:" + mDecayAverage + " Mag Max:" + mMagnitudeBuffer.max(mPeakMagnitude));
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mPeakMagnitude = -8.0f;
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mAttackAverage = -8.0f;
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mDecayAverage = -8.0f;
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mDelayBuffer.reset(0.0f);
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mMagnitudeBuffer.reset(mPeakMagnitude);
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}
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/**
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@@ -130,15 +122,14 @@ public class AutomaticGainControl
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*/
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public float process(float currentSample)
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{
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float delayedSample = mDelayBuffer.putAndGet(currentSample);
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float delayedSample = mDelayBuffer.get(currentSample);
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double gain = MANUAL_AGC_GAIN;
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float gain = MANUAL_AGC_GAIN;
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if(mAGCEnabled)
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{
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double currentMagnitude = FastMath.log10(FastMath.abs(currentSample) + MIN_CONSTANT) - FastMath.log10(MAX_AMPLITUDE);
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double delayedMagnitude = mMagnitudeBuffer.get(currentMagnitude);
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float currentMagnitude = (float)(FastMath.log10(FastMath.abs(currentSample) + MIN_CONSTANT) - FastMath.log10(MAX_AMPLITUDE));
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float delayedMagnitude = mMagnitudeBuffer.get(currentMagnitude);
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if(currentMagnitude > mPeakMagnitude)
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{
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@@ -148,29 +139,30 @@ public class AutomaticGainControl
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else if(delayedMagnitude == mPeakMagnitude)
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{
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/* If delayed magnitude is the current peak, then find a new peak */
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mPeakMagnitude = mMagnitudeBuffer.max();
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mPeakMagnitude = mMagnitudeBuffer.max(-3.4845634f);
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}
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/* Exponential decay mode */
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if(mPeakMagnitude > mAttackAverage)
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{
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mAttackAverage = ((1.0 - ATTACK_RISE_ALPHA) * mAttackAverage) + (ATTACK_RISE_ALPHA * mPeakMagnitude);
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mAttackAverage = ((1.0f - ATTACK_RISE_ALPHA) * mAttackAverage) + (ATTACK_RISE_ALPHA * mPeakMagnitude);
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}
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else
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{
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mAttackAverage = ((1.0 - ATTACK_FALL_ALPHA) * mAttackAverage) + (ATTACK_FALL_ALPHA * mPeakMagnitude);
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mAttackAverage = ((1.0f - ATTACK_FALL_ALPHA) * mAttackAverage) + (ATTACK_FALL_ALPHA * mPeakMagnitude);
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}
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if(mPeakMagnitude > mDecayAverage)
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{
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mDecayAverage = ((1.0 - DECAY_RISE_ALPHA) * mDecayAverage) + (DECAY_RISE_ALPHA * mPeakMagnitude);
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mDecayAverage = ((1.0f - DECAY_RISE_ALPHA) * mDecayAverage) + (DECAY_RISE_ALPHA * mPeakMagnitude);
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}
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else
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{
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mDecayAverage = ((1.0 - DECAY_FALL_ALPHA) * mDecayAverage) + (DECAY_RISE_ALPHA * mPeakMagnitude);
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mDecayAverage = ((1.0f - DECAY_FALL_ALPHA) * mDecayAverage) + (DECAY_RISE_ALPHA * mPeakMagnitude);
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}
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double magnitude = FastMath.max(mAttackAverage, mDecayAverage);
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float magnitude = FastMath.max(mAttackAverage, mDecayAverage);
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if(magnitude < KNEE)
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{
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@@ -178,11 +170,24 @@ public class AutomaticGainControl
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}
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else
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{
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gain = AGC_OUT_SCALE * FastMath.pow(10.0, magnitude * (GAIN_SLOPE - 1.0));
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gain = AGC_OUT_SCALE * (float)FastMath.pow(10.0, magnitude * (GAIN_SLOPE - 1.0));
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}
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System.out.println("Current Mag: " + currentMagnitude + " Delay Mag: " + delayedMagnitude +
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" Peak:" + mPeakMagnitude + " Gain:" + gain +
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" Attack Avg:" + mAttackAverage + " Decay Avg:" + mDecayAverage);
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}
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return (float)(delayedSample * gain);
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if(gain < mMinGain)
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{
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mMinGain = gain;
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}
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if(gain > mMaxGain)
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{
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mMaxGain = gain;
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}
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return delayedSample * gain;
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}
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/**
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@@ -202,4 +207,5 @@ public class AutomaticGainControl
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{
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return mAGCEnabled;
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}
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}
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