/fldigi-3.21.41/src/mt63/mt63base.cxx

/*
 *	mt63base.cxx  --  MT63 transmitter and receiver in C++ for LINUX
 *
 *	Copyright (C) 1999-2004 Pawel Jalocha, SP9VRC
 *	Copyright (c) 2007-2011 Dave Freese, W1HKJ
 *
 *	base class for use by fldigi
 *	modified from original
 *	excluded CW_ID which is a part of the base modem class for fldigi
 *	changed all floats to double and removed all float functions/methods
 *	changed from int* to double* for all sound card buffer transfers
 *
 *	Modified base class for rx and tx to allow variable center frequency
 *	for baseband signal
 *
 *	based on mt63 code by Pawel Jalocha
 *
 *	This file is part of fldigi.
 *
 *	Fldigi is free software: you can redistribute it and/or modify
 *	it under the terms of the GNU General Public License as published by
 *	the Free Software Foundation, either version 3 of the License, or
 *	(at your option) any later version.
 *
 *	Fldigi is distributed in the hope that it will be useful,
 *	but WITHOUT ANY WARRANTY; without even the implied warranty of
 *	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *	GNU General Public License for more details.
 *
 *	You should have received a copy of the GNU General Public License
 *	along with fldigi.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#include <config.h>

#include <stdio.h> // only for control printf's
// #include <alloc.h>
#include <iostream>

#include "dsp.h"

#include "mt63base.h"

#include "symbol.dat"	  // symbol shape
#include "mt63intl.dat" // interleave patterns

// W1HKJ
// fixed filter shapes replaced by maximally flat blackman3 filters
// that are generated as required as signal center frequency is changed

//#include "alias_k5.dat" // anti-alias filter shapes
//#include "alias_1k.dat" // for 500, 1000 and 2000 Hz modes
//#include "alias_2k.dat"


// ==========================================================================
// MT63 transmitter code

MT63tx::MT63tx()
{
	TxVect = NULL;
	dspPhaseCorr = NULL;
}

MT63tx::~MT63tx()
{
	free(TxVect);
	free(dspPhaseCorr);
}

void MT63tx::Free(void)
{
	free(TxVect);
	TxVect = NULL;
	free(dspPhaseCorr);
	dspPhaseCorr = NULL;
	Encoder.Free();
	FFT.Free();
	Window.Free();
	Comb.Free();
	WindowBuff.Free();
}

// W1HKJ
// added freq paramter to Preset
int MT63tx::Preset(double freq, int BandWidth, int LongInterleave)
{
	int i, p, step, incr, mask;

// W1HKJ
// values used to computer the blackman3 passband filter shape
	double hbw = 1.5*BandWidth / 2;
	double omega_low = (freq - hbw);
	double omega_high = (freq + hbw);
	if (omega_low < 100) omega_low = 100;
	if (omega_high > 4000) omega_high = 4000;
	omega_low *= (M_PI / 4000);
	omega_high *= (M_PI / 4000);

	mask = FFT.Size - 1;
	DataCarriers = 64;

	switch(BandWidth) {
		case 500:
			FirstDataCarr = (int)floor((freq - BandWidth / 2.0) * 256 / 500 + .5);
			AliasFilterLen = 128;
			DecimateRatio = 8;
			break;
		case 1000:
			FirstDataCarr = (int)floor((freq - BandWidth / 2.0) * 128 / 500 + 0.5);
			AliasFilterLen = 64;
			DecimateRatio = 4;
			break;
		case 2000:
			FirstDataCarr = (int)floor((freq - BandWidth / 2.0) * 64 / 500 + 0.5);
			AliasFilterLen = 64;
			DecimateRatio = 2;
			break;
		  default:
			  return -1;
	}

	WindowLen = SymbolLen;
	TxWindow = SymbolShape;
	TxAmpl = 4.0 / DataCarriers; // for maximum output level we can set TxAmpl=4.0/DataCarriers
	CarrMarkCode = 0x16918BBEL;
	CarrMarkAmpl = 0;

	if (LongInterleave) {
		DataInterleave = 64;
		InterleavePattern = LongIntlvPatt;
	}
	else {
		DataInterleave = 32;
		InterleavePattern = ShortIntlvPatt;
	}

	if (dspRedspAllocArray(&TxVect, DataCarriers))
		goto Error;
	if (dspRedspAllocArray(&dspPhaseCorr, DataCarriers))
		goto Error;
	if (WindowBuff.EnsureSpace(2 * WindowLen))
		goto Error;
	WindowBuff.Len = 2 * WindowLen;

	if (Encoder.Preset(DataCarriers, DataInterleave, InterleavePattern, 1))
		goto Error;
	if (FFT.Preset(WindowLen))
		goto Error;
	if (Window.Preset(WindowLen, SymbolSepar / 2, TxWindow))
		goto Error;

// W1HKJ
// Preset the combining instance, NULL pointers in lieu of fixed filter shapes
// blackman3 filter provides flat passband and sufficient out-of-band rejection
// to insure that all unwanted FFT components (periodic signal) are suppressed
// by 70 dB or more
	if ( Comb.Preset( AliasFilterLen, NULL, NULL, DecimateRatio ) )
		goto Error;
// compute new combining filter shape
	Comb.ComputeShape(omega_low, omega_high, dspWindowBlackman3);

// Preset the initial dspPhase for each data carrier.
// Here we only compute indexes to the FFT twiddle factors
// so the actual vector is FFT.Twiddle[TxVect[i]]

	for (step = 0, incr = 1, p = 0, i = 0; i < DataCarriers; i++) {
		TxVect[i] = p;
		step += incr;
		p = (p + step) & mask;
	}

// compute dspPhase correction between successive FFTs separated by SymbolSepar
// Like above we compute indexes to the FFT.Twiddle[]

	incr = (SymbolSepar * DataCarrSepar) & mask;
	for (p = (SymbolSepar * FirstDataCarr) & mask, i = 0; i < DataCarriers; i++) {
		dspPhaseCorr[i] = p;
		p = (p + incr) & mask;
	}
	return 0;
Error:
	Free();
	return -1;
}

// W1HKJ
// SendTune and ProcessTxVect are both modified to allow the FirstDataCarr
// to be other than WindowLen / 2 as in the original design
// The peridocity of the FFT is taken advantage of by computing the positions
// of the bit indices modulo FFT.size, i.e. r = FFT.BitRevIdx[c &  (FFT.Size - 1)]

int MT63tx::SendTune(bool twotones)
{
	int i, c, r, mask;
	double Ampl;

	mask = FFT.Size - 1;
	Ampl = TxAmpl * sqrt(DataCarriers / 2);

	for (i = 0; i < DataCarriers; i++)
		TxVect[i] = (TxVect[i] + dspPhaseCorr[i]) & mask;

	for (i = 0; i < 2 * WindowLen; i++)
		WindowBuff.Data[i].im = WindowBuff.Data[i].re = 0.0;

// W1HKJ
// first tone at the lowest most MT63 carrier
	i = 0;
	c = FirstDataCarr;
	r = FFT.BitRevIdx[c & mask];
	WindowBuff.Data[r].re = Ampl * FFT.Twiddle[TxVect[i]].re;
	WindowBuff.Data[r].im = (-Ampl) * FFT.Twiddle[TxVect[i]].im;

// W1HKJ
// 2nd tone at the highest most MT63 carrier + 1
// MT63 is specified as 500, 1000 and 2000 Hz wide signal format, but in
// fact are narrower by one carrier spacing, i.e. 0 to N-1 carriers where
// N = 64

	if (twotones) {
		i = DataCarriers - 1;
		c = (FirstDataCarr + i * DataCarrSepar);
		r = WindowLen + FFT.BitRevIdx[c & mask];
		WindowBuff.Data[r].re = Ampl * FFT.Twiddle[TxVect[i]].re;
		WindowBuff.Data[r].im = (-Ampl) * FFT.Twiddle[TxVect[i]].im;
	}

// inverse FFT: WindowBuff is already scrambled
	FFT.CoreProc(WindowBuff.Data);
	FFT.CoreProc(WindowBuff.Data + WindowLen);

// negate the imaginary part for the IFFT
	for (i = 0; i < 2 * WindowLen; i++)
		WindowBuff.Data[i].im *= (-1.0);

// process the FFT values to produce a complex time domain vector
	Window.Process(&WindowBuff);

// W1HKJ
// convert the complex time domain vector to a real time domain signal
// suitably filtered by the anti-alias filter used in the combiner
	Comb.Process(&Window.Output);

	return 0;
}

int MT63tx::SendChar(char ch)
{
	int i,mask,flip;

	Encoder.Process(ch); // encode and interleave the character

// print the character and the DataBlock being sent
//	printf("0x%02x [%c] => ", ch, ch>=' ' ? ch : '.');
//	for (i=0; i<DataCarriers; i++) printf("%c",'0'+Encoder.Output[i]);
//  printf("\n");

// here we encode the Encoder.Output into dspPhase flips

	mask = FFT.Size - 1;
	flip = FFT.Size / 2;
	for (i = 0; i < DataCarriers; i++) {
// data bit = 1 => only dspPhase correction
		if (Encoder.Output[i])
			TxVect[i] = (TxVect[i] + dspPhaseCorr[i]) & mask;
// data bit = 0 => dspPhase flip + dspPhase correction
		else
			TxVect[i] = (TxVect[i] + dspPhaseCorr[i] + flip) & mask;
	}

	ProcessTxVect();
	return 0;
}

int MT63tx::SendJam(void)
{
	int i,mask,left,right;
	int j = 0;

	mask = FFT.Size-1;
	left = FFT.Size / 4;
	right = 3 * (FFT.Size / 4);
	for (i = 0; i < DataCarriers; i++) {
		j = i & mask;
		if (rand() & 0x100) // turn left 90 degrees
			TxVect[j] = (TxVect[j] + dspPhaseCorr[j] + left) & mask;
		else				// turn right 90 degrees
			TxVect[j] = (TxVect[j] + dspPhaseCorr[j] + right) & mask;
	}

	ProcessTxVect();
	return 0;
}

// W1HKJ
// principal change from original is modulo arithmetic used to creat
// WindowBuff.Data vectors

int MT63tx::ProcessTxVect(void)
{
	int i, c, r, mask;

	mask = FFT.Size - 1;

	for (i = 0; i < 2 * WindowLen; i++)
		WindowBuff.Data[i].im = WindowBuff.Data[i].re = 0.0;

	for ( i = 0, c = FirstDataCarr; i < DataCarriers; i++, c += DataCarrSepar) {
		r = FFT.BitRevIdx[c & mask] + WindowLen * (i & 1);
		WindowBuff.Data[r].re = TxAmpl*FFT.Twiddle[TxVect[i]].re;
		WindowBuff.Data[r].im = (-TxAmpl)*FFT.Twiddle[TxVect[i]].im;
	}
	FFT.CoreProc(WindowBuff.Data);
	FFT.CoreProc(WindowBuff.Data + WindowLen);

// negate the imaginary part for the IFFT
	for (i = 0; i < 2 * WindowLen; i++)
		WindowBuff.Data[i].im *= (-1.0);

	Window.Process(&WindowBuff);

// W1HKJ
// audio output to be sent out is in Comb.Output
	Comb.Process(&Window.Output);

  return 0;
}

int MT63tx::SendSilence(void)
{
	Window.ProcessSilence(2);
	Comb.Process(&Window.Output);
	return 0;
}

// ==========================================================================
// Character encoder and block interleave for the MT63 modem

MT63encoder::MT63encoder()
{
	IntlvPipe = NULL;
	WalshBuff = NULL;
	Output = NULL;
	IntlvPatt=NULL;
}

MT63encoder::~MT63encoder()
{
	free(IntlvPipe);
	free(WalshBuff);
	free(Output);
	free(IntlvPatt);
}

void MT63encoder::Free()
{
	free(IntlvPipe);
	free(WalshBuff);
	free(Output);
	free(IntlvPatt);
	IntlvPipe = NULL;
	WalshBuff = NULL;
	Output = NULL;
	IntlvPatt = NULL;
}

int MT63encoder::Preset(int Carriers, int Intlv, int *Pattern, int PreFill)
{
	int i, p;
	if (!dspPowerOf2(Carriers)) goto Error;

	DataCarriers = Carriers;
	IntlvLen = Intlv;
	IntlvSize = IntlvLen * DataCarriers;
	if (IntlvLen) {
		if (dspRedspAllocArray(&IntlvPipe, IntlvSize)) goto Error;
		if (PreFill)
			for (i = 0; i < IntlvSize; i++)
				IntlvPipe[i] = rand() & 1;
		else
			dspClearArray(IntlvPipe,IntlvSize);
		if (dspRedspAllocArray(&IntlvPatt, DataCarriers)) goto Error;
		IntlvPtr = 0;
	}
	if (dspRedspAllocArray(&WalshBuff, DataCarriers)) goto Error;
	if (dspRedspAllocArray(&Output, DataCarriers)) goto Error;
	CodeMask = 2 * DataCarriers - 1;

	for (p = 0, i = 0; i < DataCarriers; i++) {
		IntlvPatt[i] = p * DataCarriers;
		p += Pattern[i];
		if (p >= IntlvLen) p -= IntlvLen;
	}
	return 0;

Error:
	Free();
	return -1;
}

int MT63encoder::Process(char code) // encode an ASCII character "code"
{
	int i, k;
	code &= CodeMask;
	for (i = 0; i < DataCarriers; i++)
		WalshBuff[i] = 0;
	if (code < DataCarriers)
		WalshBuff[(int)code] = 1.0;
	else WalshBuff[code-DataCarriers] = (-1.0);

	dspWalshInvTrans(WalshBuff, DataCarriers);

	if (IntlvLen) {
		for (i = 0; i < DataCarriers; i++)
			IntlvPipe[IntlvPtr + i] = (WalshBuff[i] < 0.0);
		for (i = 0; i < DataCarriers; i++) {
			k = IntlvPtr + IntlvPatt[i];
			if (k >= IntlvSize)
				k -= IntlvSize;
			Output[i] = IntlvPipe[k+i];
		}
		IntlvPtr += DataCarriers;
		if (IntlvPtr >= IntlvSize)
			IntlvPtr -= IntlvSize;
	} else
		for (i = 0; i < DataCarriers; i++)
			Output[i] = (WalshBuff[i] < 0.0);

	return 0;
}

// After encoding the "Output" array contains the bits to be transmitted

// ==========================================================================
// MT63 decoder and deinterleaver

MT63decoder::MT63decoder()
{
	IntlvPipe = NULL;
	IntlvPatt = NULL;
	WalshBuff = NULL;
	DecodeSnrMid = NULL;
	DecodeSnrOut = NULL;
	DecodePipe = NULL;
}

MT63decoder::~MT63decoder()
{
	free(IntlvPipe);
	free(IntlvPatt);
	free(WalshBuff);
	free(DecodeSnrMid);
	free(DecodeSnrOut);
	free(DecodePipe);
}

void MT63decoder::Free()
{
	free(IntlvPipe);
	IntlvPipe = NULL;
	free(IntlvPatt);
	IntlvPatt = NULL;
	free(WalshBuff);
	WalshBuff = NULL;
	free(DecodeSnrMid);
	free(DecodeSnrOut);
	DecodeSnrMid = NULL;
	DecodeSnrOut = NULL;
	free(DecodePipe);
	DecodePipe = NULL;
}

int MT63decoder::Preset(int Carriers, int Intlv, int *Pattern, int Margin, int Integ)
{
	int i,p;

	if (!dspPowerOf2(Carriers)) goto Error;
	DataCarriers = Carriers;
	ScanLen = 2 * Margin + 1;
	ScanSize = DataCarriers + 2 * Margin;

	dspLowPass2Coeff(Integ,W1,W2,W5);
	DecodeLen = Integ / 2;
	DecodeSize = DecodeLen * ScanLen;
	if (dspRedspAllocArray(&DecodePipe, DecodeSize)) goto Error;
	dspClearArray(DecodePipe, DecodeSize);
	DecodePtr = 0;

	IntlvLen = Intlv; // printf("%d:",IntlvLen);
	if (dspRedspAllocArray(&IntlvPatt, DataCarriers)) goto Error;
	for (p = 0, i = 0; i < DataCarriers; i++) {
		IntlvPatt[i] = p * ScanSize; // printf(" %2d",p);
		p += Pattern[i];
		if (p >= IntlvLen) p -= IntlvLen;
	}
  // printf("\n");

	IntlvSize = (IntlvLen + 1) * ScanSize;
	if (dspRedspAllocArray(&IntlvPipe, IntlvSize)) goto Error;
	dspClearArray(IntlvPipe, IntlvSize);
	IntlvPtr = 0;

	if (dspRedspAllocArray(&WalshBuff, DataCarriers)) goto Error;

	if (dspRedspAllocArray(&DecodeSnrMid, ScanLen)) goto Error;
	if (dspRedspAllocArray(&DecodeSnrOut, ScanLen)) goto Error;
	dspClearArray(DecodeSnrMid, ScanLen);
	dspClearArray(DecodeSnrOut, ScanLen);

	SignalToNoise = 0.0;
	CarrOfs = 0;

	return 0;
Error:
	Free();
	return -1;
}

int MT63decoder::Process(double *data)
{
	int s, i, k;
	double  Min, Max, Sig, Noise, SNR;
	int MinPos,MaxPos,code;

	dspCopyArray(IntlvPipe + IntlvPtr, data, ScanSize);

// printf("Decoder [%d/%d/%d]: \n",IntlvPtr,IntlvSize,ScanSize);
	for (s = 0; s < ScanLen; s++) {
// printf(" %2d:",s);
		for (i = 0; i < DataCarriers; i++) {
			k = IntlvPtr - ScanSize - IntlvPatt[i];
			if (k < 0) k += IntlvSize;
			if ((s & 1) && (i & 1)) {
				k += ScanSize;
				if (k >= IntlvSize) k-=IntlvSize;
			}
			WalshBuff[i] = IntlvPipe[k + s + i];
// printf(" %4d",k/ScanSize);
		}
// printf("\n");
		dspWalshTrans(WalshBuff, DataCarriers);
		Min = dspFindMin(WalshBuff, DataCarriers, MinPos);
		Max = dspFindMax(WalshBuff, DataCarriers, MaxPos);
		if (fabs(Max) > fabs(Min)) {
			code = MaxPos + DataCarriers;
			Sig = fabs(Max);
			WalshBuff[MaxPos] = 0.0;
		} else {
			code = MinPos;
			Sig = fabs(Min);
			WalshBuff[MinPos] = 0.0;
		}
		Noise = dspRMS(WalshBuff, DataCarriers);
		if (Noise > 0.0)
			SNR = Sig/Noise;
		else SNR = 0.0;
		dspLowPass2(SNR, DecodeSnrMid[s], DecodeSnrOut[s], W1, W2, W5);
// printf("%2d: %02x => %c,  %5.2f/%5.2f=>%5.2f  <%5.2f>\n",
//	   s,code,code<' ' ? '.' : (char)code,
//	   Sig,Noise,SNR,DecodeSnrOut[s]);
		DecodePipe[DecodePtr+s]=code;
	}
	IntlvPtr += ScanSize;
	if (IntlvPtr >= IntlvSize) IntlvPtr = 0;
	DecodePtr += ScanLen;
	if (DecodePtr >= DecodeSize) DecodePtr = 0;
	Max = dspFindMax(DecodeSnrOut, ScanLen, MaxPos);
	Output = DecodePipe[DecodePtr + MaxPos];
	SignalToNoise = Max;
	CarrOfs = MaxPos - (ScanLen - 1) / 2;
/*
  code=Output;
  if ((code>=' ')||(code=='\n')||(code=='\r')) printf("%c",code);
  else if (code!='\0') printf("<%02X>",code);
*/
	return 0;
}

// ==========================================================================
// MT63 receiver code

MT63rx::MT63rx()
{
	int s;

	FFTbuff = NULL;
	FFTbuff2 = NULL;

	for (s = 0; s < 4; s++)
		SyncPipe[s] = NULL;
	SyncPhCorr = NULL;
	for (s = 0; s < 4; s++) {
		CorrelMid[s] = NULL;
		CorrelOut[s] = NULL;
	}
	dspPowerMid = NULL;
	dspPowerOut = NULL;
	for (s = 0; s < 4; s++)
		CorrelNorm[s] = NULL;
	for (s = 0; s < 4; s++)
		CorrelAver[s] = NULL;
	SymbFit = NULL;
	SymbPipe = NULL;
	FreqPipe = NULL;

	RefDataSlice = NULL;

	DataPipeLen = 0;
	DataPipe = NULL;
	DataPwrMid = NULL;
	DataPwrOut = NULL;
	DataSqrMid = NULL;
	DataSqrOut = NULL;

	DataVect = NULL;

	DatadspPhase = NULL;
	DatadspPhase2 = NULL;

	SpectradspPower = NULL;
}

MT63rx::~MT63rx()
{
	int s;

	free(FFTbuff);
	free(FFTbuff2);

	for (s = 0; s < 4; s++)
		free(SyncPipe[s]);
	free(SyncPhCorr);
	for (s = 0; s < 4; s++) {
		free(CorrelMid[s]);
		free(CorrelOut[s]);
	}
	free(dspPowerMid);
	free(dspPowerOut);
	for (s = 0; s < 4; s++)
		free(CorrelNorm[s]);
	for (s = 0; s < 4; s++)
		free(CorrelAver[s]);
	free(SymbFit);
	free(SymbPipe);
	free(FreqPipe);

	free(RefDataSlice);

	dspFreeArray2D(DataPipe, DataPipeLen);
// for (s=0; s<DataPipeLen; s++) free(DataPipe[s]); free(DataPipe);
	free(DataPwrMid);
	free(DataPwrOut);
	free(DataSqrMid);
	free(DataSqrOut);

	free(DataVect);

	free(DatadspPhase);
	free(DatadspPhase2);

	free(SpectradspPower);
}

void MT63rx::Free(void)
{
	int s;
	FFT.Free();
	InpSplit.Free();
	TestOfs.Free();
	ProcLine.Free();

	free(FFTbuff);
	FFTbuff = NULL;
	free(FFTbuff2);
	FFTbuff2 = NULL;

	for (s = 0; s < 4; s++) {
		free(SyncPipe[s]);
		SyncPipe[s] = NULL;
	}
	free(SyncPhCorr);
	SyncPhCorr = NULL;
	for (s = 0; s < 4; s++) {
		free(CorrelMid[s]);
		CorrelMid[s] = NULL;
		free(CorrelOut[s]);
		CorrelOut[s] = NULL;
	}
	free(dspPowerMid);
	dspPowerMid = NULL;
	free(dspPowerOut);
	dspPowerOut = NULL;
	for (s = 0; s < 4; s++) {
		free(CorrelNorm[s]);
		CorrelNorm[s] = NULL;
	}
	for (s = 0; s < 4; s++) {
		free(CorrelAver[s]);
		CorrelAver[s] = NULL;
	}
	free(SymbFit);
	SymbFit = NULL;
	free(SymbPipe);
	SymbPipe = NULL;
	free(FreqPipe);
	FreqPipe = NULL;

	free(RefDataSlice);
	RefDataSlice = NULL;

	dspFreeArray2D(DataPipe, DataPipeLen);
// for (s=0; s<DataPipeLen; s++) free(DataPipe[s]); free(DataPipe);

	DataPipeLen = 0;
	DataPipe = NULL;

	free(DataPwrMid);
	free(DataPwrOut);
	DataPwrMid = NULL;
	DataPwrOut = NULL;
	free(DataSqrMid);
	free(DataSqrOut);
	DataSqrMid = NULL;
	DataSqrOut = NULL;

	free(DataVect);
	DataVect = NULL;

	free(DatadspPhase);
	DatadspPhase = NULL;
	free(DatadspPhase2);
	DatadspPhase2 = NULL;

	Decoder.Free();

	free(SpectradspPower);
	SpectradspPower = NULL;
}

// added freq parameter to Preset
int MT63rx::Preset(double freq, int BandWidth, int LongInterleave, int Integ,
		   void (*Display)(double *Spectra, int Len))
{
	int err,s,i,c;

// W1HKJ
// variables used for generating the anti-alias filter
	double hbw = 1.5*BandWidth / 2;
	double omega_low = (freq - hbw);
	double omega_high = (freq + hbw);
	if (omega_low < 100) omega_low = 100;
	if (omega_high > 4000) omega_high = 4000;
	omega_low *= (M_PI / 4000);
	omega_high *= (M_PI/ 4000);

	switch(BandWidth) {
	case 500:
		FirstDataCarr = (int)floor((freq - BandWidth / 2.0) * 256 / 500 + 0.5);
		AliasFilterLen = 128;
		DecimateRatio = 8;
		break;
	case 1000:
		FirstDataCarr = (int)floor((freq - BandWidth / 2.0) * 128 / 500 + 0.5);
		AliasFilterLen = 64;
		DecimateRatio = 4;
		break;
	case 2000:
		FirstDataCarr = (int)floor((freq - BandWidth / 2.0) * 64 / 500 + 0.5);
		AliasFilterLen = 64;
		DecimateRatio = 2;
		break;
	default:
		return -1;
	}

	DataCarriers = 64;	// 64 carriers

	WindowLen = SymbolLen;	// the symbol length
	RxWindow = SymbolShape;	// the symbol shape

// RxWindow, WindowLen, SymbolSepar, DataCarrSepar are tuned one for another
// to minimize inter-symbol interference (ISI) and one should not change
// them independently or ISI will increase.

	CarrMarkCode = 0x16918BBEL;

	IntegLen = Integ;	// sync. integration period
	SymbolDiv = 4;		// don't change this
	ScanMargin = 8;		// we look 8 data carriers up and down
	SyncStep = SymbolSepar/SymbolDiv;

	ProcdspDelay = IntegLen * SymbolSepar;

	TrackPipeLen = IntegLen;

	if (LongInterleave) {
		DataInterleave = 64;
		InterleavePattern = LongIntlvPatt;
	} else {
		DataInterleave = 32;
		InterleavePattern = ShortIntlvPatt;
	}

	DataScanMargin = 8;

	err = FFT.Preset(WindowLen);
	if (err) goto Error;

	if (dspRedspAllocArray(&FFTbuff, WindowLen))  goto Error;
	if (dspRedspAllocArray(&FFTbuff2, WindowLen)) goto Error;
	WindowLenMask = WindowLen - 1;

// W1HKJ
// InpSplit is the anti-aliasing filter that converts a real time domain
// signal into a complex time domain signal with pre-filtering.
// the black3man3 filter provides very sharp skirts with a flat
// passband.  
	err = InpSplit.Preset(AliasFilterLen, NULL, NULL, DecimateRatio);
	if (err) goto Error;
	err = InpSplit.ComputeShape(omega_low, omega_high, dspWindowBlackman3);
	if (err) goto Error;

	err = TestOfs.Preset(-0.25 * (2.0 * M_PI / WindowLen)); // for decoder tests only
	if (err) goto Error;

	err = ProcLine.Preset(ProcdspDelay + WindowLen + SymbolSepar);
	if (err) goto Error;
	SyncProcPtr = 0;

	ScanFirst = FirstDataCarr - ScanMargin * DataCarrSepar; // first FFT bin to scan
	if (ScanFirst < 0) ScanFirst += WindowLen;
	ScanLen = (DataCarriers + 2 * ScanMargin) * DataCarrSepar; // number of FFT bins to scan

	for (s = 0; s < SymbolDiv; s++) {
		if (dspRedspAllocArray(&SyncPipe[s], ScanLen)) goto Error;
		dspClearArray(SyncPipe[s], ScanLen);
	}
	SyncPtr = 0;

	if (dspRedspAllocArray(&SyncPhCorr, ScanLen)) goto Error;

	for (c = (ScanFirst * SymbolSepar) & WindowLenMask, i = 0; i < ScanLen; i++) {
		SyncPhCorr[i].re = FFT.Twiddle[c].re * FFT.Twiddle[c].re -
						   FFT.Twiddle[c].im * FFT.Twiddle[c].im;
		SyncPhCorr[i].im = 2 * FFT.Twiddle[c].re * FFT.Twiddle[c].im;
		c = (c + SymbolSepar) & WindowLenMask;
	}

	for (s = 0; s < SymbolDiv; s++) {
		if (dspRedspAllocArray(&CorrelMid[s], ScanLen)) goto Error;
		dspClearArray(CorrelMid[s], ScanLen);
		if (dspRedspAllocArray(&CorrelOut[s], ScanLen)) goto Error;
		dspClearArray(CorrelOut[s], ScanLen);
	}
	dspLowPass2Coeff(IntegLen, W1, W2, W5);

	if (dspRedspAllocArray(&dspPowerMid, ScanLen)) goto Error;
	dspClearArray(dspPowerMid, ScanLen);
	if (dspRedspAllocArray(&dspPowerOut, ScanLen)) goto Error;
	dspClearArray(dspPowerOut, ScanLen);
	dspLowPass2Coeff(IntegLen * SymbolDiv, W1p, W2p, W5p);

	for (s = 0; s < SymbolDiv; s++) {
		if (dspRedspAllocArray(&CorrelNorm[s], ScanLen)) goto Error;
	}

	FitLen = 2 * ScanMargin * DataCarrSepar;

	for (s = 0; s < SymbolDiv; s++) {
		if (dspRedspAllocArray(&CorrelAver[s], FitLen)) goto Error;
	}

	if (dspRedspAllocArray(&SymbFit, FitLen)) goto Error;

	if (dspRedspAllocArray(&SymbPipe, TrackPipeLen)) goto Error;
	dspClearArray(SymbPipe, TrackPipeLen);
	if (dspRedspAllocArray(&FreqPipe, TrackPipeLen)) goto Error;
	dspClearArray(FreqPipe, TrackPipeLen);
	TrackPipePtr = 0;

	SymbFitPos = ScanMargin * DataCarrSepar;
	SyncLocked = 0;
	SyncSymbConf = 0.0;
	SyncFreqOfs = 0.0;
	SyncFreqDev = 0.0;
	SymbPtr = 0;
	SyncSymbShift = 0.0;

	SyncHoldThres = 1.5 * sqrt(1.0 / (IntegLen * DataCarriers));
	SyncLockThres = 1.5 * SyncHoldThres;

	DataProcPtr = (-ProcdspDelay);

	DataScanLen = DataCarriers + 2 * DataScanMargin;
	DataScanFirst = FirstDataCarr - DataScanMargin * DataCarrSepar;

	if (dspRedspAllocArray(&RefDataSlice, DataScanLen)) goto Error;
	dspClearArray(RefDataSlice, DataScanLen);

	dspFreeArray2D(DataPipe, DataPipeLen);
	DataPipeLen = IntegLen / 2;
	dspLowPass2Coeff(IntegLen, dW1, dW2, dW5);
	if (dspAllocArray2D(&DataPipe, DataPipeLen, DataScanLen)) {
		DataPipeLen = 0;
		goto Error;
	}
	dspClearArray2D(DataPipe, DataPipeLen, DataScanLen);

	DataPipePtr = 0;

	if (dspRedspAllocArray(&DataPwrMid, DataScanLen)) goto Error;
	dspClearArray(DataPwrMid, DataScanLen);
	if (dspRedspAllocArray(&DataPwrOut, DataScanLen)) goto Error;
	dspClearArray(DataPwrOut, DataScanLen);

	if (dspRedspAllocArray(&DataSqrMid, DataScanLen)) goto Error;
	dspClearArray(DataSqrMid, DataScanLen);
	if (dspRedspAllocArray(&DataSqrOut, DataScanLen)) goto Error;
	dspClearArray(DataSqrOut, DataScanLen);

	if (dspRedspAllocArray(&DataVect, DataScanLen)) goto Error;

	if (dspRedspAllocArray(&DatadspPhase, DataScanLen)) goto Error;
	if (dspRedspAllocArray(&DatadspPhase2, DataScanLen)) goto Error;

	err = Decoder.Preset(DataCarriers, DataInterleave,
						 InterleavePattern, DataScanMargin, IntegLen);
	if (err) goto Error;

	SpectraDisplay = Display;
	if (SpectraDisplay) {
		if (dspRedspAllocArray(&SpectradspPower, WindowLen))
			goto Error;
	}
	return 0;

Error:
	Free();
	return -1;
}

int MT63rx::Process(double_buff *Input)
{
	int s1,s2;

//  TestOfs.Omega+=(-0.005*(2.0*M_PI/512)); // simulate frequency drift

	Output.Len = 0;

// W1HKJ
// convert the real data input into a complex time domain signal,
// anti-aliased using the blackman3 filter
// subsequent rx signal processing takes advantage of the periodic nature
// of the resultant FFT of the anti-aliased input signal.  Actual decoding
// is at baseband.

	InpSplit.Process(Input);

	ProcLine.Process(&InpSplit.Output);
//  TestOfs.Process(&InpSplit.Output);
//  ProcLine.Process(&TestOfs.Output);

// printf("New input, Len=%d/%d\n",Input->Len,ProcLine.InpLen);

	while((SyncProcPtr+WindowLen) < ProcLine.InpLen) {
		SyncProcess(ProcLine.InpPtr + SyncProcPtr);
// printf("SyncSymbConf=%5.2f, SyncLock=%d, SyncProcPtr=%d, SyncPtr=%d, SymbPtr=%d, SyncSymbShift=%5.1f, SyncFreqOfs=%5.2f =>",
//		SyncSymbConf,SyncLocked,SyncProcPtr,SyncPtr,SymbPtr,SyncSymbShift,SyncFreqOfs);
		if (SyncPtr == SymbPtr) {
			s1 = SyncProcPtr - ProcdspDelay +
				 ((int)SyncSymbShift - SymbPtr * SyncStep);
		s2 = s1 + SymbolSepar / 2;
//	  printf(" Sample at %d,%d (SyncProcPtr-%d), time diff.=%d\n",s1,s2,SyncProcPtr-s1,s1-DataProcPtr);
		DataProcess(ProcLine.InpPtr + s1, ProcLine.InpPtr + s2,
					SyncFreqOfs, s1 - DataProcPtr);
		DataProcPtr = s1;
	}
// printf("\n");
	SyncProcPtr += SyncStep;
	}
	SyncProcPtr -= ProcLine.InpLen;
	DataProcPtr -= ProcLine.InpLen;
	return 0;
}

void MT63rx::DoCorrelSum(dspCmpx *Correl1, dspCmpx *Correl2, dspCmpx *Aver)
{
	dspCmpx sx;
	int i, s, d;

	s = 2 * DataCarrSepar;
	d = DataCarriers * DataCarrSepar;
	sx.re = sx.im = 0.0;
	for (i = 0; i < d; i+=s) {
		sx.re += Correl1[i].re;
		sx.im += Correl1[i].im;
		sx.re += Correl2[i].re;
		sx.im += Correl2[i].im;
	}
	Aver[0].re = sx.re / DataCarriers;
	Aver[0].im = sx.im / DataCarriers;
	for (i = 0; i < (FitLen-s); ) {
		sx.re -= Correl1[i].re;
		sx.im -= Correl1[i].im;
		sx.re -= Correl2[i].re;
		sx.im -= Correl2[i].im;
		sx.re += Correl1[i+d].re;
		sx.im -= Correl1[i+d].im;
		sx.re += Correl2[i+d].re;
		sx.im -= Correl2[i+d].im;
		i += s;
		Aver[i].re = sx.re / DataCarriers;
		Aver[i].im = sx.im / DataCarriers; }
}

void MT63rx::SyncProcess(dspCmpx *Slice)
{
	int i, j, k, r, s, s2;
	double pI, pQ;
	dspCmpx Correl;
	dspCmpx *PrevSlice;
	double I, Q;
	double dI, dQ;
	double P,A;
	double w0, w1;
	double Fl, F0, Fu;
	dspCmpx SymbTime;
	double SymbConf, SymbShift, FreqOfs;
	double dspRMS;
	int Loops, Incl;

	SyncPtr = (SyncPtr + 1) & (SymbolDiv - 1); // increment the correlators pointer

	for (i = 0; i < WindowLen; i++) {
		r = FFT.BitRevIdx[i];
		FFTbuff[r].re = Slice[i].re * RxWindow[i];
		FFTbuff[r].im = Slice[i].im * RxWindow[i];
	}
	FFT.CoreProc(FFTbuff);

	if (SpectraDisplay) {
		for ( i = 0,
				j = FirstDataCarr + (DataCarriers / 2) * DataCarrSepar -
				WindowLen / 2;
			  (i < WindowLen) && ( j <WindowLen); i++,j++)
			SpectradspPower[i] = dspPower(FFTbuff[j]);
		for (j = 0; (i < WindowLen) && (j < WindowLen); i++,j++)
			SpectradspPower[i] = dspPower(FFTbuff[j]);
		(*SpectraDisplay)(SpectradspPower, WindowLen);
	}

// EnvSync.Process(FFTbuff); // experimental synchronizer

	PrevSlice = SyncPipe[SyncPtr];
	for (i = 0; i < ScanLen; i++) {
		k = (ScanFirst+i) & WindowLenMask;
		I = FFTbuff[k].re;
		Q = FFTbuff[k].im;
		P = I * I + Q * Q;
		A = sqrt(P);
		if (P > 0.0) {
			dI = (I * I - Q * Q) / A;
			dQ = (2 * I * Q) / A;
		} else {
			dI = dQ = 0.0;
		}
		dspLowPass2(P, dspPowerMid[i], dspPowerOut[i], W1p, W2p, W5p);
		pI = PrevSlice[i].re * SyncPhCorr[i].re -
			 PrevSlice[i].im * SyncPhCorr[i].im;
		pQ = PrevSlice[i].re * SyncPhCorr[i].im +
			 PrevSlice[i].im * SyncPhCorr[i].re;
		Correl.re = dQ * pQ + dI * pI;
		Correl.im = dQ * pI - dI * pQ;
		dspLowPass2(&Correl, CorrelMid[SyncPtr] + i,
					CorrelOut[SyncPtr] + i, W1, W2, W5);
		PrevSlice[i].re = dI;
		PrevSlice[i].im = dQ;
	}

	if (SyncPtr == (SymbPtr^2)) {
		for (s = 0; s < SymbolDiv; s++) { // normalize the correlations
			for (i = 0; i < ScanLen; i++) {
				if (dspPowerOut[i] > 0.0) {
					CorrelNorm[s][i].re = CorrelOut[s][i].re / dspPowerOut[i];
					CorrelNorm[s][i].im = CorrelOut[s][i].im / dspPowerOut[i];
				} else
					CorrelNorm[s][i].im = CorrelNorm[s][i].re = 0.0;
			}
		}

/*
	// another way to normalize - a better one ?
	for (i=0; i<ScanLen; i++)
	{ for (P=0.0,s=0; s<SymbolDiv; s++)
		P+=dspPower(CorrelOut[s][i]);
	  if (P>0.0)
	  { for (s=0; s<SymbolDiv; s++)
		{ CorrelNorm[s][i].re=CorrelOut[s][i].re/P;
		  CorrelNorm[s][i].im=CorrelOut[s][i].im/P; }
	  } else
	  { for (s=0; s<SymbolDiv; s++)
		  CorrelNorm[s][i].re=CorrelNorm[s][i].im=0.0; }
	}
*/
// make a sum for each possible carrier positions
		for (s = 0; s < SymbolDiv; s++) {
			s2 = (s + SymbolDiv / 2) & (SymbolDiv - 1);
			for (k = 0; k < 2 * DataCarrSepar; k++)
				DoCorrelSum( CorrelNorm[s] + k,
							 CorrelNorm[s2] + k + DataCarrSepar,
							 CorrelAver[s] + k);
		}
// symbol-shift dspPhase fitting
		for (i = 0; i < FitLen; i++)  {
			SymbFit[i].re = dspAmpl(CorrelAver[0][i]) -
							dspAmpl(CorrelAver[2][i]);
			SymbFit[i].im = dspAmpl(CorrelAver[1][i]) -
							dspAmpl(CorrelAver[3][i]);
		}

//	P=dspFindMaxdspPower(SymbFit+30,4,j); j+=30;
		P = dspFindMaxdspPower(SymbFit + 2, FitLen- 4 , j);
		j += 2;
//	printf("[%2d,%2d]",j,SymbFitPos);
		k = (j - SymbFitPos) / DataCarrSepar;
		if (k > 1)
			j -= (k - 1) * DataCarrSepar;
		else if (k < (-1))
			j -= (k + 1) * DataCarrSepar;
		SymbFitPos = j;
//	printf(" => %2d",j);
		if (P > 0.0) {
			SymbConf = dspAmpl(SymbFit[j]) +
					   0.5 * (dspAmpl(SymbFit[j + 1]) + dspAmpl(SymbFit[j - 1]));
			SymbConf *= 0.5;
			I = SymbFit[j].re + 0.5 * (SymbFit[j - 1].re + SymbFit[j + 1].re);
			Q = SymbFit[j].im + 0.5 * (SymbFit[j - 1].im + SymbFit[j + 1].im);
			SymbTime.re = I;
			SymbTime.im = Q;
			SymbShift = (dspPhase(SymbTime) / (2 * M_PI)) * SymbolDiv;
			if (SymbShift < 0)
				SymbShift += SymbolDiv;
	  // for (i=j-1; i<=j+1; i++) printf(" [%+5.2f,%+5.2f]",SymbFit[i].re,SymbFit[i].im);
	  // make first estimation of FreqOfs
	  // printf(" -> [%+5.2f,%+5.2f] =>",I,Q);
	  // for (i=j-2; i<=j+2; i++) printf(" %+6.3f",I*SymbFit[i].re+Q*SymbFit[i].im);
			pI =  dspScalProd(I, Q, SymbFit[j])
				+ 0.7 * dspScalProd(I, Q, SymbFit[j - 1])
				+ 0.7 * dspScalProd(I, Q, SymbFit[j + 1]);
			pQ =  0.7 * dspScalProd(I, Q, SymbFit[j + 1])
				- 0.7 * dspScalProd(I, Q, SymbFit[j - 1])
				+ 0.5 * dspScalProd(I, Q, SymbFit[j + 2])
				- 0.5 * dspScalProd(I, Q, SymbFit[j - 2]);
			FreqOfs = j + dspPhase(pI, pQ) / (2.0 * M_PI / 8);
/* SYNC TEST */
	  // refine the FreqOfs
			i = (int)floor(FreqOfs + 0.5);
			s = (int)floor(SymbShift);
			s2 = (s + 1) & (SymbolDiv - 1);
//	  printf(" [%5.2f,%2d,%d,%d] ",FreqOfs,i,s,s2);
			w0 = (s + 1 - SymbShift);
			w1 = (SymbShift - s);
//	  printf(" [%4.2f,%4.2f] ",w0,w1);
			A = (0.5 * WindowLen) / SymbolSepar;
			I = w0 * CorrelAver[s][i].re + w1 * CorrelAver[s2][i].re;
			Q = w0 * CorrelAver[s][i].im + w1 * CorrelAver[s2][i].im;
//	  printf(" [%5.2f,%2d] -> [%+5.2f,%+5.2f]",FreqOfs,i,I,Q);
//	  FreqOfs=i+dspPhase(I,Q)/(2.0*M_PI)*0.5*A;
//	  printf(" => %5.2f",FreqOfs);
			F0 = i + dspPhase(I, Q) / (2.0 * M_PI) * A - FreqOfs;
			Fl = F0 - A;
			Fu = F0 + A;
			if (fabs(Fl) < fabs(F0))
				FreqOfs += (fabs(Fu) < fabs(Fl)) ? Fu : Fl;
			else
				FreqOfs += (fabs(Fu) < fabs(F0)) ? Fu : F0;
//	  printf(" => (%5.2f,%5.2f,%5.2f) => %5.2f",Fl,F0,Fu,FreqOfs);

		} else {
			SymbTime.re = SymbTime.im = 0.0;
			SymbConf = 0.0;
			SymbShift = 0.0;
			FreqOfs = 0.0;
		}

	// here we have FreqOfs and SymbTime.re/im

	// printf("FreqOfs=%5.2f",FreqOfs);

		if (SyncLocked) { // flip the SymbTime if it doesn't agree with the dspAverage
			if (dspScalProd(SymbTime, AverSymb) < 0.0) {
				SymbTime.re = (-SymbTime.re);
				SymbTime.im = (-SymbTime.im);
				FreqOfs -= DataCarrSepar;
			}
	  // reduce the freq. offset towards the dspAverage offset
			A = 2 * DataCarrSepar;
			k = (int)floor((FreqOfs - AverFreq) / A + 0.5);
			FreqOfs -= k * A;
/* SYNC TEST */
			A = (0.5 * WindowLen) / SymbolSepar;
			F0 = FreqOfs - AverFreq; // correct freq. auto-correlator wrap
			Fl = F0 - A;
			Fu = F0 + A;
			if (fabs(Fl) < fabs(F0))
				FreqOfs += (fabs(Fu) < fabs(Fl)) ? A : -A;
			else
				FreqOfs += (fabs(Fu) < fabs(F0)) ? A : 0.0;
// printf(" => (%5.2f,%5.2f,%5.2f) => %5.2f",Fl,F0,Fu,FreqOfs);

		} else { // of if (SyncLocked)
// flip SymbTime if it doesn't agree with the previous
			if (dspScalProd(SymbTime, SymbPipe[TrackPipePtr]) < 0.0) {
				SymbTime.re = (-SymbTime.re);
				SymbTime.im = (-SymbTime.im);
				FreqOfs -= DataCarrSepar;
			}
// reduce the FreqOfs towards zero
			A = 2 * DataCarrSepar;
			k = (int)floor(FreqOfs / A + 0.5);
			FreqOfs -= k * A;
/* SYNC TEST */
			F0 = FreqOfs - FreqPipe[TrackPipePtr];
			Fl = F0 - A;
			Fu = F0 + A;
			if (fabs(Fl) < fabs(F0))
				FreqOfs += (fabs(Fu) < fabs(Fl)) ? A : -A;
			else
				FreqOfs += (fabs(Fu) < fabs(F0)) ? A : 0.0;
		}

// printf(" => [%+5.2f,%+5.2f], %5.2f",SymbTime.re,SymbTime.im,FreqOfs);

		TrackPipePtr += 1;
		if (TrackPipePtr >= TrackPipeLen)
			TrackPipePtr -= TrackPipeLen;
		SymbPipe[TrackPipePtr] = SymbTime;  // put SymbTime and FreqOfs into pipes
		FreqPipe[TrackPipePtr] = FreqOfs;   // for averaging

// find dspAverage symbol time
		Loops = dspSelFitAver( SymbPipe,
							   TrackPipeLen,
							   (double)3.0,
							   4,
							   AverSymb,
							   dspRMS,
							   Incl);
// printf(" AverSymb=[%+5.2f,%+5.2f], dspRMS=%5.3f/%2d",
//		 AverSymb.re,AverSymb.im,dspRMS,Incl);
// find dspAverage freq. offset
		Loops = dspSelFitAver( FreqPipe,
							   TrackPipeLen,
							   (double)2.5,
							   4,
							   AverFreq,
							   dspRMS,
							   Incl);
		SyncFreqDev = dspRMS;
// printf(" AverFreq=%+5.2f, dspRMS=%5.3f/%2d",AverFreq,dspRMS,Incl);

		SymbConf = dspAmpl(AverSymb);
		SyncSymbConf = SymbConf;
		SyncFreqOfs = AverFreq;
		if (SymbConf > 0.0) {
			SymbShift = dspPhase(AverSymb) / (2 * M_PI) * SymbolSepar;
			if (SymbShift < 0.0)
				SymbShift += SymbolSepar;
			SymbPtr = (int)floor((dspPhase(AverSymb) / (2 * M_PI)) * SymbolDiv);
			if (SymbPtr < 0)
				SymbPtr += SymbolDiv;
			SyncSymbShift = SymbShift;
		}

		if (SyncLocked) {
			if ((SyncSymbConf < SyncHoldThres) || (SyncFreqDev > 0.250))
				SyncLocked = 0;
		} else {
			if ((SyncSymbConf > SyncLockThres) && (SyncFreqDev < 0.125))
				SyncLocked = 1;
		}

		SyncSymbConf *= 0.5;

// printf(" => SyncLocked=%d, SyncSymbShift=%5.1f, SymbPtr=%d",
//		SyncLocked,SyncSymbShift,SymbPtr);

// printf("\n");

	} // enf of if (SyncPtr==(SymbPtr^2))

}

void MT63rx::DataProcess(dspCmpx *EvenSlice, dspCmpx *OddSlice, double FreqOfs, int TimeDist)
{
	int i, c, r;
	dspCmpx Freq, Phas;
	int incr, p;
	double I, Q, P;
	dspCmpx Dtmp;
	dspCmpx Ftmp;

//  double Aver,dspRMS; int Loops,Incl;

// Here we pickup a symbol in the data history. The time/freq. synchronizer
// told us where it is in time and at which frequency offset (FreqOfs)
// TimeDist is the distance in samples from the symbol we analyzed
// in the previous call to this routine

//  FreqOfs=0.0; // for DEBUG only !

//  printf("DataProcess: FreqOfs=%5.3f, TimeDist=%d, Locked=%d\n",
//	 FreqOfs,TimeDist,SyncLocked);

	P = (-2 * M_PI * FreqOfs) / WindowLen;	// make ready for frequency correction
	Freq.re = cos(P);
	Freq.im = sin(P);
	Phas.re = 1.0;
	Phas.im = 0.0;
	for (i = 0; i < WindowLen; i++) {		// prepare slices for the FFT
		r = FFT.BitRevIdx[i];			// multiply by window and pre-scramble
//	if (i==2*ScanMargin)
//	  printf("%3d: [%5.2f,%5.2f] [%5.2f,%5.2f]\n",
//		i, dspPhase.re,dspPhase.im, EvenSlice[i].re,EvenSlice[i].im);
		CdspcmpxMultAxB(I, Q, EvenSlice[i], Phas);
		FFTbuff[r].re = I * RxWindow[i];
		FFTbuff[r].im = Q * RxWindow[i];
		CdspcmpxMultAxB(I, Q, OddSlice[i], Phas);
		FFTbuff2[r].re = I * RxWindow[i];
		FFTbuff2[r].im = Q * RxWindow[i];
		CdspcmpxMultAxB(Dtmp, Phas, Freq);
		Phas = Dtmp;
	}
	FFT.CoreProc(FFTbuff);
	FFT.CoreProc(FFTbuff2);
/*
  printf("FFTbuff [%3d...]:",FirstDataCarr-16);
  for (i=FirstDataCarr-16; i<=FirstDataCarr+32; i++)
	printf(" %+3d/%4.2f",i-FirstDataCarr,dspAmpl(FFTbuff[i]));
  printf("\n");

  printf("FFTbuff2[%3d...]:",FirstDataCarr-16);
  for (i=FirstDataCarr-16; i<=FirstDataCarr+32; i++)
	printf(" %+3d/%4.2f",i-FirstDataCarr,dspAmpl(FFTbuff2[i]));
  printf("\n");
*/
//  printf(" FreqOfs=%5.2f: ",FreqOfs);

//  printf("Symbol vectors:\n");
	incr = (TimeDist * DataCarrSepar) & WindowLenMask;	// correct FFT dspPhase shift
	p = (TimeDist * DataScanFirst) & WindowLenMask;	// due to time shift by
	for (c = DataScanFirst, i = 0; i < DataScanLen; ) {	// TimeDist
// printf("%2d,%3d:",i,c);
// printf("  [%6.3f,%6.3f]  [%6.3f,%6.3f]",
//	 FFTbuff[c].re,FFTbuff[c].im,
//	FFTbuff2[c+DataCarrSepar].re,FFTbuff2[c+DataCarrSepar].im);
// printf("   [%6.3f,%6.3f]/[%6.3f,%6.3f]",
//	FFTbuff2[c].re,FFTbuff2[c].im,
//	FFTbuff[c+DataCarrSepar].re,FFTbuff[c+DataCarrSepar].im);
// printf(" %5.3f/%5.3f",dspAmpl(FFTbuff[c]),dspAmpl(FFTbuff[c+DataCarrSepar]));
// printf(" %5.3f/%5.3f",dspAmpl(FFTbuff2[c+DataCarrSepar]),dspAmpl(FFTbuff2[c]));
// printf("\n");
		Phas = FFT.Twiddle[p];
		CdspcmpxMultAxB(Dtmp, RefDataSlice[i], Phas);
		CdspcmpxMultAxBs(DataVect[i], FFTbuff[c], Dtmp);
//	printf("%3d,%2d: [%8.5f,%8.5f] / %8.5f\n",
//	   c,i,FFTbuff[c].re,FFTbuff[c].im,DataPwrOut[i]);
		dspLowPass2( dspPower(FFTbuff[c]),
					 DataPwrMid[i],
					 DataPwrOut[i], dW1, dW2, dW5);
		RefDataSlice[i++] = FFTbuff[c];
		c = (c + DataCarrSepar) & WindowLenMask;
		p = (p + incr) & WindowLenMask;

		Phas = FFT.Twiddle[p];
		CdspcmpxMultAxB(Dtmp, RefDataSlice[i], Phas);
		CdspcmpxMultAxBs(DataVect[i], FFTbuff2[c], Dtmp);
//	printf("%3d,%2d: [%8.5f,%8.5f] / %8.5f\n",
//	   c,i,FFTbuff2[c].re,FFTbuff2[c].im,DataPwrOut[i]);
		dspLowPass2( dspPower(FFTbuff2[c]),
					 DataPwrMid[i],
					 DataPwrOut[i], dW1, dW2, dW5);
		RefDataSlice[i++] = FFTbuff2[c];
		c = (c + DataCarrSepar) & WindowLenMask;
		p = (p + incr) & WindowLenMask;
	}

	P = (-TimeDist * 2 * M_PI * FreqOfs) / WindowLen;
	Freq.re = cos(P);
	Freq.im = sin(P);
	for (i = 0; i < DataScanLen; i++) {
		CdspcmpxMultAxB(Ftmp, DataVect[i], Freq);
// dspLowPass2(dspPower(Ftmp),DataPwrMid[i],DataPwrOut[i],dW1,dW2,dW5);
// CdspcmpxMultAxB(Dtmp,Ftmp,Ftmp);
// Dtmp.re=Ftmp.re*Ftmp.re-Ftmp.im*Ftmp.im; Dtmp.im=2*Ftmp.re*Ftmp.im;
// dspLowPass2(&Dtmp,DataSqrMid+i,DataSqrOut+i,dW1,dW2,dW5);
		DataVect[i] = DataPipe[DataPipePtr][i];
		DataPipe[DataPipePtr][i] = Ftmp;
	}
	DataPipePtr += 1;
	if (DataPipePtr >= DataPipeLen)
		DataPipePtr = 0;

	for (i = 0; i < DataScanLen; i++) {
		if (DataPwrOut[i] > 0.0) {
			P = DataVect[i].re / DataPwrOut[i];
			if (P > 1.0)
				P = 1.0;
			else if (P < (-1.0))
				P = (-1.0);
			DatadspPhase[i] = P;
		} else
			DatadspPhase[i] = 0.0;
	}
	Decoder.Process(DatadspPhase);
	Output.EnsureSpace(Output.Len + 1);
	Output.Data[Output.Len] = Decoder.Output;
	Output.Len += 1;
/*
  printf("Demodulator output vectors:\n");
  for (i=0; i<DataScanLen; i++)
  { printf("%2d: [%8.5f,%8.5f] / %8.5f => %8.5f\n",
	   i,DataVect[i].re,DataVect[i].im,DataPwrOut[i], DatadspPhase[i]);
  }
*/
/*
  for (i=0; i<DataScanLen; i++)
  { // printf("%2d: [%8.5f,%8.5f]\n",i,DataVect[i].re,DataVect[i].im);
	if (dspPower(DataVect[i])>0.0) P=dspPhase(DataVect[i]); else P=0.0;
	DatadspPhase[i]=P;
	P*=2; if (P>M_PI) P-=2*M_PI; else if (P<(-M_PI)) P+=2*M_PI;
	DatadspPhase2[i]=P;
	printf("%2d: %6.3f [%6.3f,%6.3f]  [%8.5f,%8.5f], %5.2f, %5.2f",
	   i, DataPwrOut[i], DataSqrOut[i].re,DataSqrOut[i].im,
		  DataVect[i].re,DataVect[i].im, DatadspPhase[i],DatadspPhase2[i]);
	if (DataPwrOut[i]>0.0)
	  printf(" %6.3f",dspAmpl(DataSqrOut[i])/DataPwrOut[i]);
	printf("\n");
  }
  Loops=dspSelFitAver(DatadspPhase2,DataScanLen,(double)2.5,4,Aver,dspRMS,Incl);
  printf("Aver=%5.2f, dspRMS=%5.2f, Incl=%d\n",Aver,dspRMS,Incl);
*/
}

int MT63rx::SYNC_LockStatus(void) {
	return SyncLocked;
}

double MT63rx::SYNC_Confidence(void) {
	return SyncSymbConf <= 1.0 ? SyncSymbConf : 1.0;
}

double MT63rx::SYNC_FreqOffset(void) {
	return SyncFreqOfs / DataCarrSepar;
}

double MT63rx::SYNC_FreqDevdspRMS(void) {
	return SyncFreqDev / DataCarrSepar;
}

double MT63rx::SYNC_TimeOffset(void) {
	return SyncSymbShift / SymbolSepar;
}

double MT63rx::FEC_SNR(void) {
	return Decoder.SignalToNoise;
}

int MT63rx::FEC_CarrOffset(void) {
	return Decoder.CarrOfs;
}

double MT63rx::TotalFreqOffset(void) {
	return ( SyncFreqOfs + DataCarrSepar * Decoder.CarrOfs) *
		   (8000.0 / DecimateRatio) / WindowLen;
}