RDATEQDecoder.h

//
// Copyright 2018, Jeremy Cooper
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
//
// 1. Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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#ifndef RDAT_EQ_DECODER_H
#define RDAT_EQ_DECODER_H

#include <sys/types.h>
#include "EQSymbolDecoder.h"

class RDATEQDecoder
{
public:
	RDATEQDecoder(float sampleRate);
	virtual ~RDATEQDecoder();
	
	void SetSymbolDecoder(EQSymbolDecoder *b);
	void Process(float *samples, size_t count);
	void Stop();

	void SetClockRatioThreshold(float threshhold);
	void SetClockAlpha(float alpha);
	
private:
	bool ClockDetect(float sample);
	void EvaluateClock(void);

	//
	// The upstream receive to whom we should send decoded bits.
	//
	EQSymbolDecoder *mDecoder;
	
	//
	// Clock detection variables.
	//
	float *mSyncWindow;
	int    mSyncWindowSize;
	int    mSyncWindowCurPos;
	int    mSyncWindowSyncPos;
	int    mSyncWindowEvalPos;
	int    mSyncWindowNextEvalPos;
	
	bool   mClockDetected;
	
	//
	// Minimum ratio between peak level and valley level that
	// is considered a good clock lock.
	//
	float mClockRatioThreshold;
	
	//
	// Alpha to use in clock window filter.
	//
	float mClockAlpha;
};

#endif