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#7 NXDN Decoder support. Redesigns tuner and channel frequency error management. (#2431)

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Closes #7 

NXDN Decoder

* Implements: NXDN4800, NXDN9600, Type-C and Type-D decoding and trunk tracking.
* Redesigns tuner and channel frequency error management.
This commit is contained in:
Denny Sheirer
2026-07-08 03:44:08 -04:00
committed by GitHub
parent a053315675
commit 7945f0ce63
445 changed files with 30854 additions and 2053 deletions
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29
src/main/java/io/github/dsheirer/module/decode/FeedbackDecoder.java
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@@ -1,6 +1,6 @@
/*
* *****************************************************************************
* Copyright (C) 2014-2025 Dennis Sheirer
* Copyright (C) 2014-2026 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
@@ -29,8 +29,19 @@ import io.github.dsheirer.source.SourceEvent;
*/
public abstract class FeedbackDecoder extends PrimaryDecoder implements ISourceEventProvider
{
private static final double TWO_PI = 2 * Math.PI;
private Listener<SourceEvent> mSourceEventListener;
private Listener<Float> mSymbolListener;
private double mSampleRate;
/**
* Sets the decimated final sample rate that will be used for reporting decoder PLL errors.
* @param rate in Hertz
*/
protected void setDecimatedSampleRate(double rate)
{
mSampleRate = rate;
}
/**
* Protocol description suitable for display in the user interface
@@ -68,13 +79,19 @@ public abstract class FeedbackDecoder extends PrimaryDecoder implements ISourceE
}
/**
* Processes the current phase-locked loop (PLL) measurement and sends to the parent tuner for self correction.
* @param pllError as measured in the decoder.
* Processes the current phase-locked loop (PLL) measurement and sends to the channel frequency error manager to
* correct the error by mixing the incoming sample stream to remove the error.
*
* Note: this source event error measurement is rebroadcast by the ProcessingChain and received by the
* ChannelFrequencyErrorManager that lives within the TunerChannelSource where it adjusts the channel's mixer to
* incrementally correct and drive the error toward zero in concert with the parent tuner's auto PPM correction.
*
* @param pllError as measured in the decoder, in Radians.
*/
public void processPLLError(float pllError, int baudRate)
public void processPLLError(float pllError)
{
long frequencyError = (long)(baudRate / 2.0 * (pllError / Math.PI));
broadcast(SourceEvent.frequencyErrorMeasurementSyncLocked(frequencyError, "Decoder measured error sync locked"));
long correctionRequestHertz = (long)(mSampleRate / TWO_PI * pllError);
broadcast(SourceEvent.frequencyCorrectionRequest(correctionRequestHertz));
}
/**