mirror of
https://github.com/DSheirer/sdrtrunk.git
synced 2026-11-12 08:37:25 -05:00
c3d52ff86e
Changes to model, view and controller components and updates all gui editors. Removes the configuration panel and tree and replaces with 3 new panels. Updates playlist.xml to a new playlist_v2.xml format.
113 lines
3.4 KiB
Java
113 lines
3.4 KiB
Java
package dsp.gain;
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import sample.complex.Complex;
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import sample.complex.ComplexSampleListener;
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import buffer.FloatCircularBuffer;
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/*******************************************************************************
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* SDR Trunk
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* Copyright (C) 2015 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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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>
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*
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* This class is modeled using concepts detailed in the GNURadio
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* implementation of feed forward AGC class located at:
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* https://github.com/gnuradio/gnuradio/blob/master/gr-analog/lib/
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* feedforward_agc_cc_impl.cc
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*
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******************************************************************************/
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public class ComplexFeedForwardGainControl implements ComplexSampleListener
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{
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public static final float OBJECTIVE_ENVELOPE = 1.0f;
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public static final float MINIMUM_ENVELOPE = 0.0001f;
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private ComplexSampleListener mListener;
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private FloatCircularBuffer mEnvelopeHistory;
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private float mMaxEnvelope = 0.0f;
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private float mGain = 1.0f;
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/**
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* Dynamic gain control for incoming sample stream to amplify or attenuate
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* all samples toward an objective unity)gain, using the maximum envelope
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* value detected in the stream history window.
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*
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* Uses the specified damping factor to limit gain swings. Damping factor
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* is applied against the delta between current gain value and a recalculated
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* gain value to limit how quickly the gain value will increase or decrease.
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*
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* @param window - history size to use in detecting maximum envelope value
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* @param damping - a value between 0 < damping <= 1.0;
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*/
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public ComplexFeedForwardGainControl( int window )
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{
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mEnvelopeHistory = new FloatCircularBuffer( window );
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}
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public void dispose()
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{
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mListener = null;
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}
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@Override
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public void receive( float inphase, float quadrature )
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{
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float envelope = Complex.envelope( inphase, quadrature );
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if( envelope > mMaxEnvelope )
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{
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mMaxEnvelope = envelope;
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adjustGain();
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}
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/* Replace oldest envelope value with current envelope value */
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float oldestEnvelope = mEnvelopeHistory.get( envelope );
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/* If the oldest envelope value was the max envelope value, then we
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* have to rediscover the max value from the envelope history */
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if( mMaxEnvelope == oldestEnvelope && mMaxEnvelope != envelope )
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{
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mMaxEnvelope = MINIMUM_ENVELOPE;
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for( float value: mEnvelopeHistory.getBuffer() )
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{
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if( value > mMaxEnvelope )
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{
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mMaxEnvelope = value;
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}
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}
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adjustGain();
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}
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/* Apply current gain value to the sample and send to the listener */
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if( mListener != null )
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{
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mListener.receive( inphase *= mGain, quadrature *= mGain );
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}
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}
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private void adjustGain()
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{
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mGain = OBJECTIVE_ENVELOPE / mMaxEnvelope;
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}
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public void setListener( ComplexSampleListener listener )
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{
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mListener = listener;
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}
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}
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